FSC 102 - Plant Propagation and Nursery Management PDF

FSC 102. PLANT PROPAGATION AND NURSERY MANAGEMENT (1+1) Lecture 1. Scope and importance of plant propagation, Agencies involved in the development of nursery, government schemes and economics Introduction Propagating new plants is both a science and an art. The study of it can provide a lifetime of challenges and opportunities to learn more about this fascinating craft, or a basic knowledge of it can provide the students with the skills and techniques to start their own business in nursery production of horticultural plants since the demand for planting material of horticultural plants is ever increasing. It can be of great fun to grow your own plants. You may already have some experience growing different plants. Plant propagation is the multiplication of plants by both sexual and asexual means. To start with, start growing a few tomato plants from seeding in kitchen garden, to the conservationist growing endangered species of orchids in test tubes, to the commercial nurseries that grow the millions of annuals, perennials, bulbs, shrubs and trees sold every year, a working knowledge of plant propagation makes all of these endeavors possible. This chapter will give the students greater confidence in producing plants from seed, cuttings, grafting, budding, layering and specialized vegetative structures along with essential skills to work in the horticulture industry. Agriculture and Horticulture are vital sciences as they suffice the very basic need of food for the Human beings. Qualitative and quantitative food can essentially be produced from healthy plants which in turn are produced only when their seedlings/sapplings are vigorous and healthy. Nursery is consequently the basic need of horticulture. Plant propagation techniques and practices is the core of horticulture nurseries. The planting materials for horticultural plantations are raised from seeds and vegetative parts. Role of Mother Plants is very primary and important. The fate of nursery depends on quality and truthfulness of mother plants. A good nursery entrepreneur does not depend on others for procurement of mother plants. Mother plants are required for both stock and scion. Mother plants should be selected on the basis of its genetic traits and other factors like availability and adaptation in the growing environment. Scope and Importance of Plant Propagation in Horticulture Most of the horticultural plants, particularly the fruit trees, are perennial in nature. Some of the fruit trees survive and produce fruits for about 100 years. Horticulture has a significant role in human nutrition. It plays a prime role in wealth generation and socio economic status of the farmers. Most of the horticultural crops are propagated vegetatively for which nursery units are necessary. There are plentiful programs being implemented to develop the nurseries and there by bringing about horticultural development. Importance of Plant Propagation for Landscaping Landscaping one’s home is a very personal process. A garden should necessarily be unique and reflect the owner personality. The value of a designed garden or landscape escalates with its age. Same is the case with the plants. If a small evergreen plant fetches a prize of Rs. 100 at the time of planting, it is bound to fetch Rs 500 after 5 years of its growth. A designed garden not only increases the appeal and privacy of the property but it also adds to the value of the property. Nowadays, landscaping and garden architects have become a part of the modern life. To design and develop the modern corporate gardening, the professionals use periodicals and magazines which are specialized in this respect. Importance of Plant Propagation for Starting a Backyard Plant Nursery When people think of a plant nursery, the local garden center usually comes to mind. Fact is, most garden centers produce very few of the plants they sell. Instead, they procure the planting material from outside nurseries, which actually grow the plants. One finds specialty plant nurseries ranging in size from tiny backyard nurseries to giant regional wholesale nurseries, who supply retailers in the adjoining states of the country. A backyard plant nursery often specializes in plants that are in demand and can be container-grown to save space. A relatively new development in container growing called the “pot-in-pot” system, allows growers to produce larger trees and shrubs without the back- breaking hand digging and high water consumption required for field growing. For smaller plants, container growing saves time, water and transplanting. Growers who live in a small town or rural area can also make a good income focusing on wholesale plant sales to retail nurseries and landscapers around their region. Some nurseries just replant young plants obtained from wholesale specialized nurseries, rear these plants till they attain a certain size in larger pots or containers and then sell these plants. Once mother plants are obtained one can easily propagate more by cuttings or root division and reduce the plant propagation cost. This can really make a difference with ground covers and ornamental grasses, for example, because most customers need dozens of saplings, not just one or two. Specific Importance of Plant Nursery 1. Seedlings and grafts are produced in nursery and the fruit orchards and ornamental gardens can be established with minimum care, cost and maintenance. 2. The nursery planting materials are available at the beginning of the planting season. This saves the time, money and efforts of the farmers to raise seedlings. 3. There is a wide scope for fruit orchards, ornamental, vegetable, and landscape gardens at public gardens, highways and co operative housing societies. 4. It assures the production of genetically improved quality planting material 5. It provides employment opportunities for technical, skilled, semi-skilled, unskilled labor 6. They are an important source supplying the seedlings for meeting the fruit, pulp and paper, fuel wood, timber and other demands of the industries Role of Nurseries in Horticulture Development 1. Production of Genetically Pure Nursery Stock Genetically pure planting material is essential for healthy and vigorous plant growth. Both stock and scion should be genetically pure. The planting material should be satisfactory in quantity and quality and easily available for further multiplication. 2. Export of Nursery Stock Globalization has improved the chances of export of quality planting material to other countries. Special techniques and care is required for exporting the nursery material. Similarly, great care is necessary while importing nursery material from outside. 3. Employment Generation There is a huge demand of skilled professionals for grafting, budding, potting, repotting and other nursery operations. Nursery provides employment opportunities for technical, skilled, semi-skilled, and unskilled labor. Nursery can itself be a very remunerative enterprise in the changing national scenario. 4. Role of Nurseries in Dry Land Horticulture Like India, there are many countries in this world, which face droughts every other year. Growing drought tolerant fruit crops provide assured income to farmers. Horticultural plantations play an essential part in afforestation and thereby help to reduce the global warming. Types of Plant Propagation Nurseries A nursery is a place where plants are propagated and grown to usable size. The various types of nurseries can be classified based on various criteria. They include, Sale: Retail nurseries which sell to the general public. Wholesale nurseries, which sell only to businesses such as other nurseries and to commercial gardeners, private nurseries which suffice the needs of institutions or private estates. Some retail and wholesale nurseries sell by mail. Phase of the process: propagation, growing out, or retail sale; Type of plant: Ground covers, shade plants, fruit trees, or rock garden plants. The nursery business is highly seasonal. It is affected by temperature, drought, cheaper foreign competition, fashion, etc. Plants may be propagated by seeds, but often desirable cultivars are propagated asexually by budding, grafting, layering, or other nursery techniques Types of Nurseries According to Type of Plants Grown 1. Fruit Plant Nurseries Fruit crops are mainly propagated vegetatively and need special techniques for propagations as well as maintenance. Mango, Guava, Pomegranate, Sapota, Oranges etc. are propagated with vegetative means. Fruit nurseries are essential for production of grafts as well as the mother plants of scions and rootstocks. 2. Vegetable Nurseries: All vegetables except few like potatoes, sweet potato, bulbous vegetables and some other are raised by seedlings. Very few vegetables are perennials like, little gourd, drumsticks, Alocasia etc. Seedlings are to be produced on a large scale in short period. 3. Ornamental Plant Nurseries: Ornamental and floricultural crops are numerous and are propagated vegetatively, like gladiolus, carnation, roses, lilies etc. There is a large group of ornamental plants, which is propagated by seeds and seedling; Asters, Marigolds, Salvias, etc 4. Medicinal and Aromatic Plant Nurseries: There is considerable increase in people adopting ayurvedic medicines with the changing life style. It is also necessary to conserve the fast depleting precious medicinal and aromatic plants. To save and multiply the valuable medicinal and other auspicious plants, nurseries specializing in these plants have begun to flourish. These plants are also demanded by the Ayurvedic medicinal practitioners. 5. Forest Plant Nursery: Forest plants are essential for synthesis of gums, honey, timber and fuel. There is lack of forest plant nurseries. To save and multiply the entire lot of valuable forest plants it is very essential to preserve and multiply those plants for which special type of nurseries are to be established. This is also needed for medicinal purposes. 6. Hi-Tech Nurseries: There is sudden increase in the demand for certain commercial plants. For example Tissue cultured banana, gerbera and carnation etc. It is not possible to fulfill this requirement by ordinary or common nursery practices. There is necessity to have special techniques and methods to meet the demand and only Hi-tech nurseries can satisfy this type of demand. These nurseries grow plants in greenhouse, building of glass or a plastic tunnel, designed to protect young plants from harsh weather, while allowing access to light and ventilation. Modern greenhouses allow automated control of temperature, ventilation, light, watering and feeding. Some also have fold-back roofs to allow "hardening-off" of plants without the need for manual transfer of plants to the outdoor beds. Types of Nurseries According to the Type of Sale 1. Retail Nurseries: Retail nurseries raise plants for sale to the general public. These places are small, locally owned nurseries that sell seasonal, annuals, ornamental trees, other landscaping plants and garden decoration to the general public or companies 2. Wholesale Nurseries: Wholesale nurseries usually grow plants in bulk for the purpose of selling to large clients. These clients may include florists, garden centers or departmental stores. A wholesale nursery may fill a niche for particular types of plants, such as vegetables or houseplants, or they may grow a general selection of plants to sell such as fruits, vegetables and landscaping plants. 3. Private Nurseries: A private nursery grows plants exclusively for a single client. The private nursery may be owned by the client or it may be under contract for use by the client. Clients for private nurseries include large estates, corporations and institutions. These nurseries are concerned with raising documented historical plants for the historic preservation of the estates. 4. Mail Order: Privately owned, retail and wholesale businesses may all be involved in mail order businesses. As shipping technology improved, it became possible to ship dormant ornamental trees and bedding plants via mail. The internet has largely shifted mail order from catalog to online shopping. Bedding plants may be shipped via postal carrier, but are primarily handled through third- party shipping agents. On the basis of irrigational facility, nurseries are classified into: 1. Dry Nursery: It is a nursery that is maintained without any irrigation or other artificial watering. 2. Wet Nursery: It is a nursery that is maintained by irrigation or other artificial watering during the dry periods. On the basis of size of seedlings, nurseries are classified into the following types: 1. Seedling nursery: A nursery which has only seedling beds, i.e., in which seedlings only are raised, no transplanting being done is called seedling nursery. 2. Transplant nursery: A nursery which has only transplant beds, in which seedlings are transplanted for preparation for forest planting is called transplant nursery. On the basis of duration of their use, nurseries are classified into: 1. Temporary Nursery: This type of nursery is developed only to fulfill the requirement of the season or a targeted project. The nurseries for production of seedlings of transplanted vegetables and flower crops are of temporary nature. Likewise temporary arrangement for growing forest seedlings for planting in particular area can also be done in temporary nursery. This nursery is maintained for supplying stock for a short period after which it is abandoned. Normally, it is constructed in the plantation area and usually small in size. It is suitable for hilly regions. o Main features: ▪ Constructed for a short period of time and smaller in size. ▪ Manuring is not necessary. ▪ Mostly located near/inside the planting area and which is appropriate chiefly for casualty replacement. ▪ Elaborate soil preparation is not necessary. ▪ Cost of transportation of seedlings to the planting sites is low. ▪ Seedlings of different species for mixed crops. ▪ Gap between lifting the stock from the nursery and actual planting is less. ▪ Special supervision is not required. o Advantages ▪ Usually constructed in newly cleared sites fairly rich in humus and so, manuring is not required. ▪ Minimum trouble with the weeds, destructive insects and diseases. ▪ Enables raising of species in their optimum altitudinal zone in hills. ▪ Cheap transport of planting stock without any serious damage or shock. o Disadvantages ▪ Comparatively costly. ▪ Difficult to supervise. ▪ Proper supervision is not possible as it is made out of way places. ▪ Due to lack of irrigation facility, the growth of seedlings is, usually slow and heavy mortality. 2. Permanent Nursery: This type of the nursery is placed permanently so as to produce plants continuously. These nurseries have all the permanent features. The permanent nursery has permanent mother plant blocks. The work goes on continuously all the year round in this nursery. It is intended to meet the requirements of one or more ranges and it is relatively larger in extent. o Main features ▪ Fit for large and intensive work and intensively managed ▪ Established whereas all the facilities are available, i.e., easy supervision, communication facilities, labours, etc. ▪ Intensive manuring and soil working are done in perpetuity ▪ Used for large scale afforestation works, or distribution to the villagers under community and private forestry programme. ▪ A large labour forces, tools and equipments are available ▪ Original cost of formation is high but is cheaper in the long run ▪ Regular skilled supervision is done o Advantages ▪ Varieties of planting stocks supply; such as root- shoot cuttings, grafted plants, layering, budding, polypot seedlings, etc. ▪ Duration of service life is long and production cost is reasonable. ▪ Meet the requirement of more ranges. ▪ Supervision cost is low and can be easily supervised. ▪ Easy transport of nursery stocks due to nearness of roads. ▪ Plants are raised year after year for a long time on same site. o Disadvantages ▪ Transportation of seedlings is difficult and costlier. ▪ Establishment cost is high. ▪ Manuring of beds annually & intensive soil working is essential. ▪ Requires large labour forces throughout the year which is difficult to available in agricultural seasons. Domestication Domestication is the process of selecting specific kinds of wild plants and adopting them to human use. Number of domesticated plant species with which early civilization developed was relatively few; determined by their usefulness and ease by which they could be propagated. Plat exchanges Exchange of plant material from the area of origin to developing countries of the world is one of the major aspects of human development. Not only had the plants, the propagation methods to reproduce them also required. Voyages of Columbus opened the world of exploration and the interchange of plant materials from continent to continent. Addition of edible food crops, new and exotic plants were being sought out for introduction. Glasshouses and green houses were invented to grow the exotic species in colder climates. Legal Authorizations for Starting Nursery Business A commercial nursery business requires a business license which is a rather lengthy process. In many cases zoning ordinances dictate possible uses for land. Normally, a nursery business would be considered an "agricultural use", but in some cases it may also be interpreted as commercial", "agribusiness", or some other classification. Permits regarding establishment of greenhouses must be taken before erection of a green house, storage building or warehouse for storing materials and equipment required in a nursery. A nursery business may require a property hazard insurance, workmen's compensation if you have paid employees and general liability insurance if you expect visitors to your nursery. Nurseries in some areas may have to fulfill the government agricultural inspection requirements as per the body governing the area. Permissions are also required from the local authorities for availing electricity, water and other facilities. Investigation of Potential Market for Plant Nursery 1. Nurseries under Horticulture Board Development Programs sponsored by State Agricultural Departments, Medicinal Boards, etc. produce plants for home gardens, landscaping, reforestation, and other uses. It should be decided as to which type of plants the nursery would produce, like the container grown, bare root, or root balled plants, etc. 2. Production of sufficient quantities of good quality material in order to satisfy the customer needs is essential. While producing more than the requirement may lead to unsold surplus which may cause losses to the nursery unit. 3. Advertising is costly but effective in horticulture nursery business. Marketing and advertising strategies must be preplanned to support each other and the business. Financial Resources for Nursery Bank Loans Terms and conditions differ from bank to bank, state to state and again the procedure for release of first installment is delayed. This may put the nursery unit in loss or trouble. Financial Resources from Government National Horticulture Mission (NHM) started in 2005 in India with an objective to establish ideal nurseries for production of genetically pure plant materials. Nurseries in the public sectors (on government establishments) are entitled to get 100 per cent subsidies on expenditure. The nurseries in the private sector get a subsidy of 50 per cent on their expenditures. There are two types of nurseries based on their sizes. Big nurseries are those with size of 1 hectare area. Such nurseries are entitled to receive financial assistance up to 30 Lakh as subsidy. The small nurseries with size of 1 Acre are entitled for a subsidy up to 18 Lakhs. The subsidies are given as per the bank loans sanctioned. Financial Resources from Nationalized Banks There are different schemes under National Horticulture Mission for establishment of horticulture nurseries: 1. Development of Orchard with Tools and Implements 2. Establishment of New Orchards 3. Sources of Irrigation Facilities 4. Controlled Farming 5. Integrated Pest Management/ Integrated Disease Management 6. Organic Farming 7. Human Resource Development 8. Practicals on Technology 9. Honey Bee Keeping 10. Post Harvest Handling of Fruits and Vegetables. 11. Self employment program. Plant propagation organizations American Seed Trade Organisation (ASTA) American Society for Horticultural Sciences (ASHS) Association of Official Seed Analysts Association of Official Seed Certifying Agencies Canadian Seed Growers Association International Dwarf Fruit Tree Association International Plant Propagators Society International Seed Testing Association International Society for Horticultural Sciences Nursery and Landscape Association Bedding Plants Foundation Society for Invitro Biology Southern Nursery Association Questions 1. ___________type of the nursery that produce plants continuously. A) Temporary nursery B) Permanent Nursery C) Open nursery D) Wet nursery 2. ________ nurseries usually grow plants in bulk for the purpose of selling to large clients. A) Wholesale B) Landscape nurseries C) Mail order nursery D) Garden centre 3. __________ nurseries are essential for production of grafts as well as the mother plants of scions and rootstocks A) Fruit B) Vegetable C) Banana D) Pine apple 4. In hi-tech nurseries, plants grow in _______ structure A) Open B) Tunnel C) Green house D) Raised bed 5. Genetically pure planting material is essential for _______ plant growth. A) Vigorous B) Reduce C) Increase D) Disease free 6. Define nursery 7. What is a temporary nursery? 8. Define propagation. Why propagation is important in horticultural crops? Lecture - 2 Establishment of nursery and site selection, propagation structures, mist chamber, shade net, phytotron, humidifiers, green house, poly house, hot beds and pit nursery Nursery Nursery is a place where plants and plant materials like seedlings, grafts and budded plants are maintained in healthy condition for planting in the main field or for sale. Advantages of nursery 1. Management of seedlings, grafts, layers and budded plants is very easy. 2. Economy in area and efficient plant protection measures can be taken up. 3. The survival percentage of seedlings, grafts, layers and budded plants in the main field will be more. 4. Commercial nursery will generate income to the entrepreneur and create employment opportunities. 5. Quality planting materials can be obtained in time. Site selection for nursery Following points are to be considered while selecting the site for the establishment of nursery 1. Nursery location should be approachable with proper transport facilities either by road or by rail. 2. The selected site should have electricity and other communication facilities 3. The soil of the site should be light to medium in texture with good fertility and sufficient water holding capacity along with good drainage. A soil pH of 6.0 to 7.0 is ideal. The site should have good quality of potable water 4. The topography of the selected land should be plain with one percent slope 5. The nursery should be located near the market area and raw materials should easily be available. 6. The nursery area should be under partial shade, preferably under trees; otherwise, artificial shade could be created by using shade nets, coconut leaves, banana trash, etc. 7. The area should be located near the source of adequate soft water throughout the year (>1400m mhos). The quality of irrigation water decides the growth and vigour of the plants. 8. The soil should be fertile with adequate humus, porous and neutral in reaction with proper drainage facilities. 9. Sufficient labourers should be available round the year. 10. Optimum temperature range between 23 - 280C 11. Nursery site should be located near the market. 12. The location should be in a well-established fruit growing region as one could get the benefit of experience of other growers. 13. The nursery should be well protected against animals and trespassers, by fencing either using barbed wires or using live fences such as Karonda, Prosopis, etc., which are amenable for pruning and training and have thorns. 14. Wind breaks from strong and hot winds must protect the nursery site. 15. The site should be a well-drained and elevated area. 16. The nursery should be located nearer to farm office for effective supervision. 17. Optimum soil conditions are essential for the success and economy of nursery operation. Clayey soil should not be selected as they are ill drained and poorly aerated, and crack during summer. Well drained loamy soils are suitable. The depth of the soil should be 50 - 60 cm for better development of roots. The extent of land required for the nursery depends upon the targets of planting material of different fruit crops, ornamental plants and varieties to be produced. For instance to produce about one lakh mango grafts at least two hectares of nursery land is required. Different features of the nursery 1. Scion banks - mother plant nursery 2. Production yard - production of plants through seeds, cuttings, budding, grafting and bio technology 3. Propagation structures - mist chambers, green houses 4. Hardening chambers and establishment structures 5. Sale point. Planning and lay out of nursery While planning and layout is done, the following components are to be taken care and provision should be made for them. 1. Fence The nursery should be well protected by fencing either using concrete posts and barbed wires or using live fences such as Karonda, Prosopis etc., which are amenable for pruning and training and have thorns. 2. Roads and paths A proper planning of roads and paths inside the nursery will not only add beauty, but also make the nursery operations easy and economical. Each road or path should lead the customer to a point of interest in the nursery area. 3. Progeny block / mother plant block / Scion bank A well managed mother plant block will not only creates confidence among the customers but also reduces the cost of production and increases the success rate of grafting or budding or layering. It is due to the availability of fresh scion materials throughout the season within the nursery itself and there will not be any lag period between separation of scion and graft. 4. Wells, sumps, pipelines etc., Sufficient number of wells to supply good quality irrigation water is necessary in the nursery. An experienced agricultural engineer may be consulted to layout pipelines. 5. Office cum stores The office building may be constructed in a place suited to supervise and to receive customers. The office room may be decorated with attractive photographs of fruit and ornamental plants propagated in the nursery with details of it. A store room of suitable size is needed for storing the inputs. 6. Seed beds This component is essential to raise the seedlings and rootstocks. Beds of one meter width and convenient length are to be made near to the water source. A working area of 60 cm between the beds is necessary. 7. Nursery beds This is meant for accommodating the plants to be raised in polythene bags. This area should also have a provision to keep the grafted plants either in trenches of 30 cm deep and one meter wide to accommodate 500 grafts or layers in each bed. Such beds can be irrigated either with a rose cane fitted to a flexible hose pipe or by overhead micro sprinklers. 8. Potting mixture and potting yard The potting mixture for different purposes can be prepared by mixing fertile red soil, well rotten FYM, leaf mould oil cakes etc., in different proportions. The potting mixture may be prepared well in advance by adding required quantity of super phosphate for better decomposition and solubulisation. Construction of a potting yard of suitable size facilitates potting or pocketing of seedlings or grafting or budding operations even on a rainy day. The other structures necessary for a scientific nursery are shade houses, green houses or poly houses. Besides, the availability of standard rootstocks is very important to produce uniform planting material with uniform qualities. For successful propagation of plants, quite a few plant-propagating structures and equipments are often used, because certain plants have special requirement for light, temperature or humidity for germination of seeds or rooting of cuttings, and also because the outdoor condition may not be suitable for growing young plants. There are several kinds of plant-growing structures, the most important ones being mist chamber, shade net, phytotron, humidifiers, green house, poly house, hot beds and pit nursery. Propagation structures Mist chamber: Mist propagation unit is to maintain continuously a film of water on the leaves, thus reducing transpiration and keeping the cutting the cuttings turgid until rooting taken place. In this way, leafy cuttings can be fully exposed to light and air because humidity remains high and prevents damage even from bright sunshine. Mist also prevents disease infection in cuttings by way of washing off fungus spores before they attack the tissues. While the leaves in this process must be kept continuously moist, it is important that only minimum water should be used. This is because excessive water leaches out nutrients from the compost, which may occur starvation. Moreover, a directly injurious effect on the cuttings may occur from over watering. Hence, it is necessary to utilize nozzles capable of producing a very fine mist. Mist chamber is useful propagating units for the rooting of cuttings, especially those which are difficult to root. A fine mist is sprayed over the cuttings intermittently at regular intervals during day and night. The mist is controlled by a time – clock, operating a magnetic solenoid valve that is set to turn the mist on far 3-5 seconds to wet the leaves, and is then turned off. When the leaves being to dry, the mist is again turned on. Shade Net Shade net house is very useful for protecting the young seedlings or rooted cuttings from the external high temperature and light intensity, and in hardening them before transplanting in the field. Sometimes, propagation beds are also constructed in the shade net house and used for propagation of plants, which are tender and less exacting in their requirement of temperature, light or humidity. Construction of shade net house varies widely and its size varies, according to the need of the propagator. Various shading materials my be used, thus allowing different intensities of light into the shadehouse. Since the transpiration and soil evaporation are appreciably reduced due to low temperature and low light intensity, less watering is required under shade, but at the same time presents mortality of plants. Phytotron Phytotrons are chambers that provide controlled environmental conditions for growing plants. Phytotrons have been extensively used for research on how various environmental factors affect plant growth and development. The environmental conditions monitored, controlledLight is provided by LEDs. Water and nutrients are provided as foliar sprays, with frequency and duration specified during the light period and the dark period. Temperature and humidity set points and control ranges can be independently specified during both the light and dark periods. Humidifiers A humidifier is an appliance that increases humidity (moisture) in a single room or in the entire house. Greenhouse cooling systems (humidification systems) facilitate seedling development and healthy plant growth by generating high volumes of ultra-fine droplets that evaporate quickly. Green house A greenhouse greatly extends the variety and scope of propagation. Many kinds of greenhouses are used for propagation but the most suitable type is the one that admit the maximum amount of light. This is important, particularly where most of the propagation is done in late winter and early spring. Good light conditions are essential for the sturdy growth of the seedlings. The framework supports should be as slender as the necessity for a certain degree of strength and stability in the structure for light obstruction. Steel and aluminum fulfill these conditions best, but are usually more expensive than timber. Green house should be run from east to west direction for better light penetration in winter and early spring and consequently preferable for raising seedling at this time of the year. Moreover, it is important that the greenhouse should be well away from any kind of shade such as a tree or buildings, including other greenhouse. Some shelter, however, from north to northeast winds is desirable. These glasshouses may be plastic polyethylene covered or made from fiberglass. Modern greenhouses are well equipped with elaborate structures and have precise control on temperature, light intensity and humidity. The size and type of greenhouse, primarily depends upon the need of the plant propagator. Glass covered greenhouse is expensive but they have long life. However, for short-term benefits, plastic covered greenhouses can also be made. Two types of plastic are available for their construction, polyethylene and fiberglass. Both are light weight and inexpensive as compared to glass. Plastic covered greenhouses are lighter than glass covered ones but there is very high increase in humidity in such houses, especially in winter, which results undesirable water drops on the plants. It can, however be, overcome by making adequate ventilation. Polyvinyl chloride has also been used in construction of greenhouses but it tends to darken pre-maturely in sunlight. Poly house Poly-house is widely used for propagating off season seedlings which fetch better price in the market. Modern poly-house are automated for temperature and humidity control to assist propagation In poly-houses, plant is propagated using pro-trays or poly-bags on ground or benches. In Poly-houses, thermostat, hygrometer, automatic ventilation system is maintained to facilitate micro-climate. Irrigation and fertigation systems in poly-houses are automated to provide measured quantity of water and nutrients to plants. Hot beds The hot beds are small low structures, used for propagation of nursery plants under controlled condition. Usually, hot bed consists of a frame, the cover and a heating system. The frame is made up wood, steel or aluminum, and covered with a plastic or glass, while heat is provides artificially below the propagating medium by hot air or water. A thermostat automatically controls the temperature. Hot beds are widely used for raising plants in western countries but in India these are rarely used as the cost involved in construction is very high. As in greenhouse, close attention must be paid in hot beds to shading and ventilation and on temperature and humidity control. For better results, hot beds should be placed in sunny location but in protected and well drained location. Hot beds can be restricted to spring, summer and fall. Pit nursery Pit nursery is highly suitable for tropical regions like plains of Tamil Nadu, Kerala and Andhra Pradesh. High temperature (>300C) prevailing under tropical environment has been found to be the most important limiting factor in nursery production. High temperature increases the transpiration rate leading to drying and desiccation of cuttings. The callus gets dried up quickly leading to failure of union in grafts and budded plants. High temperature coupled with low humidity proves to be more hazardous than high temperature alone. Pit nursery is advantageous to overcome those two limiting factors. In pit nursery, the cuttings in containers are placed in a pit of 10’ X 40’ X 3’ size and has been covered with polythene sheet at the top. The pit has to be located under shade and water is to be sprinkled at periodical intervals. Before keeping the containerized cuttings, the pit is to be filled with water and allowed to soak and drain. Further, repeated water spray will maintain the temperature of the pit less than 250 C. The polythene cover prevents evaporation of water from pit. Thus maintains high humidity which enables the cuttings to keep its turgidity and root profusely. The pit nursery will practically suit for herbaceous terminal cutting. Epicotyl grafts and soft wood grafts can be hardened under pit nurseries. Single nodal cuttings of many species can be easily made to root under pit. The outer boundary of series of pit nurseries are to protect with raised bunds which prevent entry of rain water during rainy seasons. Questions 1. ________ is a place where plants and plant materials like seedlings, grafts and budded plants are maintained in healthy condition for sale A) Nursery B) Mother block C) Orchard D) Both A and B 2. Protected greenhouse used for research and to study the interaction between plants & environment is---------------- A) Phytotron B) Humidifier C) Net house D) Hot bed 3. A device that increases humidity in the nursery structure is ---------- A) Humidifier B) Cool bad C) Ventilator D) All the above 4. ________is widely used for propagating off season seedlings A) Poly-house B) Shade net C) Cool chamber D) Both A and B 5. ________ nursery practically suit for herbaceous terminal cutting A) Pit B) Dry nursery C) Wet nursery D) Raised bed 6. Discuss the advanced environmental control systems? 7. Describe different propagation structures and their functions? Lecture – 3 Media and containers, soil sterilization, manures and manuring and liquid manures GROWING MEDIA A growing medium is defined as substance which required for roots growth and extract water and nutrients. A proper growing medium is an important factor in nursery plant production. There are three different types of growing media used in nursery plant production. The different components of growing media are sand, peat, bark, leaf mould, sawdust, bagasse, rice hulls, perlite, pumice, vermiculite, calcined clays, expanded polystyrene, urea formaldehydes etc. Several media are used by nurserymen in plant propagation by seeds or cuttings. The medium should have the following characters: (i) it should be firm enough to hold the seeds or cuttings in place during germination or rooting, (ii). It should have the ability to retain and supply sufficient moisture to the seeds or cuttings, (iii). It should be porous enough to permit aeration and drain out excess moisture, (iv). It should be free of high concentration of salts, (v). it should be free from weed seeds, harmful diseases and nematodes. Seed propagation media: These media are used for germination of seeds or establishments of germinant. The media should be sterile and it should have a fine texture to maintain high moisture around the germinating seeds. Media for rooting cuttings: These media should be porous to prevent water logging and to allow good aeration for root formation. Transplant media: These media should be coarser and contain compost for transplantation of smaller seedlings or rooted cuttings. In some cases, 1/5th part of soil may be added to encourage the development of mycorrhizal fungi and other beneficial microorganisms. A typical growing medium is composed of two or three organic and inorganic components with complementary physical and chemical properties. Organic components commonly used are peat moss, bark compost, rice hulls, coconut coir and sawdust. These organic materials are low in weight with high water holding capacity, high CEC and rich in nutrients. Inorganic components include gravel, sand, vermiculite, perlite, pumice and polystyrene beads. These inorganic components improve media properties by increasing aeration pore space, adding bulk density and enhancing drainage. Soil The soil can be defined as the portion of the earth’s crust that is formed by the decomposed of rocks and minerals by physical, chemical and biotic forces. It is composed of minerals, air, water and organic matter. An important physical property of soil is its texture, which is defined as the percentage of sand (0.02 to 2.0 mm in diameter), silt (0.02 to 0.002 mm in diameter) and clay (less than 0.002 mm in diameter). Soil with a high percentage of sand retains comparatively little moisture than soil having a high percentage of clay, which in contrast prevents aeration more compared with sandy soils. A soil consisting a mixture of 40 percent sand, 40 percent silt and 20 percent clay produces a loam soil that retains sufficient water and is good for plant growth and permits its movement without restricting aeration. Sandy loam soils are excellent ingredients for the preparation of soil mixtures for container grown plants. Sand Since sand is formed as a result of the weathering of rocks, its mineral composition depends on the type of rock from which it has been derived. Sand varies in size (0.05 to 2.0 mm in diameter) and shape. Permeability and porosity of sand medium are related to the size and shape of sand grains. Sand contains practically no mineral nutrient and has no buffering capacity. Quartz sand, comprising mainly silica, is most suitable for propagation purpose. Vermiculite Expanded mica, known as vermiculite, is widely used as a medium for seed germination and rooting of cuttings. Vermiculite is grades into four types, depending on the particle size. Vermiculite is inert in nature and light in weight, being spongy and porous it has a tremendous capacity to retain water. It is neutral in reaction, with good buffering capacity and high cation exchange capacity. It contains good amounts of magnesium and potassium. Perlite Perlite is a pearl grey white silicaceous material of volcanic origin, which is mined from lava flows. It is prepared by heating a glassy volcanic lava in furnace at 760-1204oC. Perlite is almost neutral in reaction with a pH of 7.0 to 7.5. It has no buffering capacity, cation exchange capacity or mineral nutrients. It can retain water 3 to 4 times of its weight. It is sterile, i.e. free from fungi and bacteria. Sphagnum moss Sphagnum moss is generally found in India on the hills. The dehydrated moss is relatively sterile and light in weight, with a high water holding capacity. It inhibits the growth of molds. It has a pH of about 3.5 to 4.0 m. It is widely used for keeping the live material moist for distant transport and in air layering of plants in India. A mixture of shredded sphagnum moss, soil and sand makes a good substratum for the germination of seeds. It can also be used as a rooting medium of cuttings. Leaf mold Leaf mold is prepared by decomposed leaves of various garden plants. Sometimes cow dung, urine or ammonium sulphate is added to enrich it. Leaf mold may contain nematodes, fungi and bacteria; hence it should be used only after sterilization. It is utilized to prepare soil mixtures for use as a germination medium or plant growing medium. Peat Peat contains mainly the partially decomposed parts of aquatic, marsh, bog or swamp vegetation. Its composition depends upon the vegetation from which it has originated state of decomposition, mineral content and degree of acidity. It has been classified into different types viz., moss peat, reed sedge peat and peat humus. Moss peat is commonly called as peat moss, which is derived from sphagnum or hypnum or other mosses. It is light tan to dark brown colour with highly acidic (Ph 3.2-4.5) but it has high moisture holding capacity. It contains small amount of nitrogen but little or no phosphorous and potassium. Reed sedge peat is mainly derived from the remains of grasses, reeds, sedges and other swamp plants which are brown to blackish colour. Its pH range is from 4.0 to 7.5 and has high water holding capacity. Peat humus is the highly decomposed material either of hypnum moss or reed sedge peat, which has brown to black colour or with very poor water holding capacity. Pumice It is most widely used alone or in combination with peat moss for seed propagation. It is of volcanic origin and minied in to commercial grade, which chiefly contains silicon oxide and aluminium oxide with varying amount of iron, calcium, magnesium and sodium in oxide form. It increases aeration and drainage in rooting mixtures if used in combination with other propagating media. Leaf mould Leaf mould is prepared by decomposing fallen leaves of the plants. Sometimes, chemical fertilizers, farmyard manures or cowdung are also added to it. It contains almost all the essential nutrient elements in it. Leaf mould should be properly treated with fungicides and insecidies before use to kill the pathogens. Compost Compost is prepared by decomposing bulk organic wastes biologically under controlled conditions in piles or bins. Compost is a rich source of mineral nutrients with good water holding capacity. It can be used as a medium for propagation but should be mixed with soil. Cocopeat It is also called as coco dust. It is a byproduct of cutting and shifting of coconuts for fibre production. It is becoming very popular propagating and growing medium now-a-days because it has an excellent pore space (25-30 per cent) and fine structure required for proper growth and development of seedlings. Moreover, it is a rich source of nutrients and can easily be mixed with other growing media. Rock wool It is derived from basalt rock, melted at a temperature 1600oC, then cooled and spun into fibres. Rock wool, which is used as a rooting medium, is available in several forms as shredded, pellets, slabs, blocks, cubes etc. Rock wool has good water holding capacity and tetains good level of O2. Calcined clay When minerals like clay, shades etc., are heated at high temperature, they produce some stable aggregates. Such aggregates have no fertilizer value, but are porous, and resistant to break down and water absorption. Calcined clay is mainly used to mix with other growing media. Eg. Leca, terragreon, turfice, haydate and hortag. Synthetic plastic aggregates The commonly used Synthetic plastic aggregates are expanded polystyrene fractions and urea- formaldehyde foam. The polystyrene fractions are usually neutral, don’t absorb water and don’t decay. These usually improve drainage, aeration and bulk density when mixed with other media. Urea foams are usually sponge like structures having enough N content and high water holding capacity. Shredded bark, wood shavings and saw dust It can be used in mixtures with various propagating medium. Because of low cost, light weight and easy availability, these are mainly used in soil mixes for container grown plants. These mises usually contain a lower amount of nutrients and hence additional amount of nutrients may be added to the mixes before their use as a growing medium. These bark or dust may contain toxic materials when fresh. Therefore, these should be composted for 10 to 15 weeks before use. Soil mixture Many soil mixtures are used as medium for propagation. Generally, soil mixtures are prepared by mixing sand, loam soil and leaf mold in various proportions. An ideal soil mixture should be porous and should also have good water holding capacity. It should not be sticky when wet. While preparing soil mixtures, it should be free from big soil clods, weed seeds, fresh manures etc. It is a good practice to screen the soil, sand and leaf mold before mixing them together. Soil mixture are not only used as propagating medium for seed germination or rooting of cuttings but also for filling of container for growing young seedlings. In preparing container mixer, the media should be screened for uniformity to eliminate excessively large particles. In mixing, the various ingredients may be arranged inlayers in a pile and turned with a shovel. Preparation of mixture should preferable take place at least a day prior to use. During the ensuring 24 hours, the moisture should tend to become equalized throughout the mixture. The mixture should be just being sufficiently moist at the time use so that it does not crumble; other hand, it should not be sufficiently wet to form a ball when squeezed in the hand. With barks and other organic matter and supplementary components, particularly rice hulls and sugarcane begasse, it is necessary to compost the material for a period of months before using it a container medium component. The successful mix for small seedlings, rooted cuttings and bedding plants consists of one part each of shredded fir or hammer-milled pine bark, peat moss, perlite and sand. To this mixture is added preplant fertilizers- gypsum, dolomitic limestone and microelements. Mixes should always be analyzed for heavy metals and soluble salt levels. The usual recommended rate is that compost not comprises more than 30 percent of the volume of the mix. Excessive salt in the propagating or growing medium [EC over 2 Ms/cm (Ds per m)] can reduce plant growth, burn the foliage or even kill the plants. A pH ranges of 5.5 to 7.0 is best for the growth of most plats. Table 1: Chemical and physical properties of a growing medium Component Bulk Porosity pH CEC density Water Air Sphagnum very low very high high 3-4 very high peat moss Hypnum low very high moderate 5-7 very high peat moss Vermiculite very low very high high 6-8 high Perlite very low low high 6-8 very low Bark low moderate very high 3-6 moderate Sand very high low moderate variable low Container The types of containers for propagating and growing young liner plans are continually being developed with a goal of reducing handling costs. The size of containers for a nursery ranges from 2cm to 10cm in diameter. These containers should have adequate drainage holes, good ratio of soil volume to the amount of ground space used, strong & durable, must be easy to handle, readily available and the amount of drainage must consonance with the ratio of air to water in the root zone. Growing of plants for transplanting to the field, garden, green house and their itself up to maturity. Types of containers Flats Flats are shallows plastic, styrofoam, wooden, or metal trays, with drainage holes in the bottom. They are useful for germinating seeds or rooting cuttings, since they permit young plants to be moved easily. Commercial growers usually use standard dimensions of 30cm x 59 cm x 8 cm. they are useful for germinating seeds or rooting cuttings, since they permit young plants to be moved easily. Galvanized iron flats used but zinc released from popular flats could cause toxicity to plants. Today, the most popular flats are made of plastic and come in all shapes and sizes. The 28 x 53 cm (11 x 21 inch.) 1020 plastic flats are the industry standard. The number of cells or compartments per tray may ranges from 1 cell for a community rooting flat or seed germination tray, to 18 or more cells for a roots line tray, to 100 to 400 cells for a seedling plug tray. Clay pots The familiar red clay flower pots, long used for growing young plants, are heavy and porous and lose moisture readily. They are easily broken, and their round shape is not economical for storage space. After continuous use, toxic salt accumulations build up, requiring soaking in water before reuse. Clay pots are rarely used today in commercial propagation, except with specialized crops. Plastic pots Plastic pot are container which are round and square, have numerous advantages: they are nonporous, reusable, light weight, and use little storage space because they will nest. Some types are fragile, however, and require careful handling, although other types, made from polyethylene, are flexible and quite sturdy. Small liner pots for direct rooting of cuttings, seedling propagation, and tissue culture plantlet acclimatization and production have gained considerable popularity. Fiber pots These pots are made from compress peat and held together with a biodegradable net. The roots are easily penetrating the container walls, so root curling does not occur. The seedling is planted together with the pot as it is biodegradable. Seeds or cuttings can be directly panted into them, roots will grow through the walls. Container of various size, round or square, are pressed into shape form peat plus wood fiber, with fertilizer added. Dry, they will keep indefinitely. Since these pots are biodegradable, they are set in the soil along with the plants. Peat pots find their best use where plants are to be held for a relatively short time and then put in a larger container or in the field. During outplanting in the field, any portion of the fiber pot transplanted above the surface of the soil will act like a wick and quickly dry out the transplant. Concrete pots Concrete pots are used in the gardens for growing the plants and not in the nurseries. These are bulky, heavy and difficult to handle. So polybags or plastic pots have taken over in most of the nurseries. Paper pots Paper pots or paper tube pots are more popular with seedling with seedling propagation of ornamental and forestry species. Paper pots consist of a series on interconnected paper cells that are arranged in a honeycomb pattern that can be separated before out planting. Paper pots are biodegradable, and the seedling plug can be planted intact into a larger container or into the ground without disturbing the root system. Some paper-machine pots come treated with copper hydroxide, which enhances root development and retards deterioration of the pot. The propagation medium is formed into a continuous cylinder and wrapped with a length of paper or cellulose skin that is glued and heat sealed. Peat, Fiber, Expanded Foam and Rockwool Blocks Polyethylene bags A low-cost method of propagating some easy-to root species is with a polyethylene plant roll. Small polyethylene bags with holes punched at the bottom for drainage are filled with the desirable growing medium, and seeds are sown or cuttings planted. The bags ate placed under suitable environmental conditions for germination or initiation of rooting. The basal ends of the cuttings are inserted in damp peat moss or sphagnum and rolled into the doubled –over plastic sheeting. The roll of cuttings is then set upringtin a humid location for rooting. Polyethyelene starter pounches with an absorbent paper inserted in the pouch are used for germinating selected seed lots. Plant rolls A low cost method of propagation some easy-to-root species is with a polyethylene plant roll. The basal ends of the cuttings are inserted in damp peat moss or sphagnum and rolled into the doubled – over plastic sheeting. The roll of cuttings is then set upright in a humid location for rooting. Polyethylene starter pouches with an absorbent paper inserted in the pouch are used for germinating selected seed lots. Plug trays Plug trays is a small sized seedlings grown in tray from expanded polystyrene or polythene filled usually with a peat or compost substrate. The plants are young plants are raised in small, individual cells, ready to be transplanted into containers or a garden. Wood container Large wood containers or boxes are used for growing large specimen trees and shrubs to provide ‘instant’ landscaping for the customer. The plant material may be kept in such containers for several years, or the plants are initially field grown and then boxed for six months to a year to let the root system acclimatize before being sold. Heavy moving equipment is required for handling such large nursery stock. Fiberglass containers: These are clean, durable, eventually discolour and with medium life span. Terracotta containers: These are very durable, tough, long lasting, heavy and expensive and plants require frequent watering. Timber containers: These are naturally attractive but vulnerable to rotting. Brass containers: These are very expensive and require polishing. Propagation blocks: These units are used for sterile propagation of plants. E,g., foamed polyurethane, mineral wool, phenolic foam and vermiculite blocks. Plastic seedling trays: These are used in mass production systems with maximum space efficiency. The trays consist of individual cells for each seedling and the most commonly used tray has 64 cells. Special plug popping pads are used to remove seedling from each cells. Both manual and mechanical plug poppers are available. Seed pans and seed boxes: Seed pans are shallow earthen pots, 10cm high and 35cm in diameter at the top. They have one large hole in the centre. Seed boxes are made of wood, 40cm wide, 60cm long, 10 cm deep with 6 to 8 holes in the bottom. Soil sterilization Sterilization in any propagation work, maintenance of sanitation is necessary, and if all necessary sanitary precautions are taken at the outset, problems will be fewer and relatively easy to manage. For all propagation work it is necessary to use a clean growing medium, sterile containers, a sanitized bench, and pathogen free plant materials. However, soil pathogens may contaminate the soil mixture even when all precautions are taken; small outbreaks of diseases can be controlled by using appropriate fungicide. Propagating media can be easily pasteurized by heat (electric or steam) or by chemicals. Expensive equipment and training of personnel are necessary for pasteurization or sterilization of propagating media. A temperature of about 71oC for 30 minutes is considered sufficient to kill almost all disease producing organisms. Fumigation is most useful for destroying harmful bacteria, fungi and nematodes in a relatively small quantity of soil that is used for propagation of plants. The most widely used soil fumigant is methyl bromide (CH3Br) a colourless, odourless and potently toxic gas, which is usually mixed with chloropicrin (Tear gas). Chloropicrin is used to indicate the presence of toxic methyl bromide, because it causes great discomfort to the eyes. Drenching the medium with certain fungicides such as Captan, Fytolan or Brassicol (1 g/ litre water), is also useful in eliminating pathogens from the medium. Beside a clean and sterile medium, disinfection of pots, flats, greenhouse benches, watering cans and other garden tools, general cleanliness is also necessary to avoid recontamination of the medium. Garden tools can be sterilized with 2 percent formaldehyde, Clorox (chlorinated water), alcohol or even boiling water. Pots, flats and propagating benches can be sterilized with steam, boiling water or 2 percent formaldehyde. Supplementary fertilizer In general, soil in the seed bed is not fertilized except by mixing with well rotten farmyard manure, compost or leaf mold. Addition of organic fertilizers is not necessary unless the soil is very poor in nutrient content. Excessive fertilization may result in soft, succulent and lanky seedlings, which cannot stand transplantation well. However, the nursery beds which support seedlings, rooted cuttings and layers or grafted plants till these are transferred to the permanent location, required supplementary fertilizers in addition to organic manures. A satisfactory fertilization programme will help in the production of healthy and stout plants with a good root and shoot system that are capable of withstanding the shocks of transplantation. As a general recommendation, for each nursery bed of 10 m2 a basal dose of 300 g ammonium sulphate, 500 g superphosphate and 100 g muriate of potash may be added during preparation of beds. If the plants are to be kept in nursery beds for a long time, top- dressing with a mixture of NPK will be helpful in maintaining a satisfactory growth of nursery plants. Slow-release fertilizer e.g. Osmocote or Nutricote give better results than highly soluble fertilizers. Manures and manuring Manures are substances of organic or inorganic nature which are capable of supplying the various plant nutrients when applied to the soil. Manures are usually divided into two groups. viz., organic and inorganic manures. Organic natural manures include excreta of animal and other matter such as blood, bones, flesh, wool, horn etc., and decomposed vegetation. They usually contain all the essential nutrients in various proportions. The inorganic manures usually supply one essential plant nutrient and hence are also called 'relative manures'. They supply either nitrogen, phosphorus or potassium. Important organic manures 1. Cattle manure or farmyard manure: The manures produced by horse, cattle or other animals are included in this category. It takes a long time to decompose, nearly an year before it becomes usable. It is more suited to light soils. This contains 0.6% N, 0.35% phosphorus and 0.6% potassium. However, the percentage of these nutrients may vary depending upon the substances in the animal feed, age of the animals, condition of animals and storage and handling including the kind of litter used. The manure is applied as a basal dressing by broadcast and immediately incorporated into the soil by ploughing. 2. Bone meal: This is rich in phosphoric acid and lime. Steamed bone meal contains not less than 3.5% N and 23% Phosphoric acid. Bone meal is especially beneficial to soil deficient in lime. 3. Oil cakes: They are residues left after the oil extraction from the seeds of groundnut, castor, gingelly, pongamia, Neem, etc. Oil cakes contain 3 to 5% N and 1.5-2% P. They are best applied to potted plants in the form of liquid manure. 4. Leaf mould: Withered and dried leaves and garden sweepings are thrown into a pit in a shady corner in the garden and covered over with earth and watered copiously once or twice in summer to assist decomposition. Decomposition will be completed within a year. Leaf mould is rich in humus and is hence applied to both sandy and clayey soils. It is usually mixed with soil in the preparation of pot mixtures. 5. Wood ash: It is rich in potassium. Vegetables generally require liberal manuring with wood ash. 6. Compost: It may be defined as the material resulting from the decomposition of plant residues under the action of bacteria and fungi which improves soil organic matter. Well-prepared compost contains 0.75-1% N, 0.60-0.75% P2O5 and 1-1.5% K2O. List of inorganic fertilizer and nutrients content Nitrogenous fertilizers - Nutrient content % a) Ammonium sulphate - 20.6 b) Urea - 46.0 c) Sodium Nitrate - 16.0 d) Potassium Nitrate - 12.5-13.5 Phosphatic fertilizers a) Super phosphate - 16.0 b) Rock phosphate - 30.0 - 40.0 Potassic fertilizers a) Muriate of potash - 60.0 b) Potassium Sulphate - 48.0 Mixed fertilizers: It is a mixture of straight fertilizers, which can supply more than one plant nutrient elements. Advantages: 1. Saving in time and labour for application. Disadvantages 1. Specific needs of crops for individual nutrient element cannot be met. 2. Unit cost of various nutrients contained in the mixed fertilizers will always be higher than the unit cost of nutrients in the straight fertilizers. Biofertilizers Fixation of atmospheric nitrogen is carried out by specific group of microroganisms either in free-living condition (Eg) Azotobacteror in symbiotic association with leguminous (eg.) Rhizobium and non-leguminous crops (eg.) Azospirillum. Application of phosphobacteria solubilizes the insoluble phosphorus thereby it increases the availability of phosphorus. They are applied in the following methods. a) Seed treatment or seed inoculation (400 g/ha) b) Seedling dip or root bacterization (1 kg/ha for 10 minutes) c) Soil application or broadcasting (2kg/ha) Liquid fertilizer For large –scale operations, it is more practical to prepare a liquid concentrate and inject it into the regular watering or irrigating system by the use of a proportioner – fertigation. The most economical source of fertilizer to be applied through the irrigation water. The soluble form of phosphorus are used, such as phosphoric acid or ammonium phosphate, in liquid feed programs. Potassium is typically applied as potassium chloride, or potassium nitrate, and nitrogen as Uran 30 (15 percent urea and 15 percent NH4NO3) or ammonium nitrate in the liquid concentrate. Fertilizers commonly used in fertigation Name N – P2O5 – K2O content Solubility (g/l) at 200 C Ammonium nitrate 34-0-0 1830 Ammonium sulphate 21-0-0 760 Urea 46-0-0 1100 Monoammonium phosphate 12-61-0 282 Diammonium phosphate 18-46-0 575 Potassium chloride 0-0-60 347 Potassium nitrate 13-0-45 316 Potassium sulphate 0-0-50 110 Monopotassium phosphate 0-52-34 230 Phosphoric acid 0-52-0 457 Specialty water soluble fertilizers S.No. Name N% P2O5 % K2O % 1. Polyfeed 19 19 19 2. Polyfeed 20 20 20 3. Polyfeed 11 42 11 4. Polyfeed 16 8 24 5. Polyfeed 19 19 19 6. Polyfeed 15 15 30 7. MAP 12 61 0 8. Multi-K 13 0 46 9. MKP 0 52 34 10. SOP 0 0 50 N fertigation Urea is well suited for injection in micro irrigation system. It is highly soluble and dissolves in non-ionic form, so that it does not react with other substances in the water. Also urea does not cause precipitation problems. Urea, ammonium nitrate, ammonium sulphate, calcium ammonium sulphate, calcium ammonium nitrate are used as nitrogenous fertilizers in drip fertigation. P fertigation Application of phosphorus to irrigation water may cause precipitation of phosphate salts. Phosphoric acid and mono ammonium phosphate appears to be more suitable for fertigation. K fertigation Application of K fertilizer does not cause any precipitation of salts. Potassium nitrate, Potassium chloride, Potassium sulphate and mono potassium phosphate are used in drip fertigation. Micro nutrients Fe, Mn, Zn, Cu, B, Mo could be used as micro nutrients in drip fertigation. Questions 1. Growing medium from decayed bog plants which is used for air layering is A) Sphagnum moss B) Perlite C) vermiculite D) Pumice 2. Soil mixture commonly used for propagation is -------------- A) 2:1:1(Red earth , FYM, Sand) B) 1:1:1 (Red earth ,FYM ,Sand ) C) 2:1 (FYM, Sand ) D) 2:1:2 (Red earth , FYM, Sand ) 3. A propagation structure used for growing and protecting young plants A) Seed nursery B) Cold frame C) Seed Bed D) Shade net house 4. ----------------- edible oilcake is used as manure A) Goat manure B) Farm yard manure C) Fish manure D) Groundnut manure 5. Optimum pH of the propagation medium is A) 4.0-5.5 B) 5.5-6.5 C) 7.5-8.5 D) 7.0-9.0 6. What is soil sterilization? 7. Write about uses of protary Lecture – 4. Advantages and disadvantages of sexual and asexual propagation Plant Propagation is defined as the multiplication of plants by both sexual and asexual means. Propagation is an art of multiplication of plants. The horticultural plants are propagated both by sexual and asexual methods. Sexual reproduction refers to multiplication of plants by seeds. Seeds are formed after successful pollination and fertilization by the union of male and female gametes. The plants raised through seed are called seedling plants. Propagation of plants by seeds offers many advantages however several have disadvantages too. Most of the horticultural plants are now propagated through grafting and budding, few through cuttings, layering, seeds and micro-propagation. The propagation methods are broadly classified as sexual, asexual and micro-propagation. Sexual Propagation Sexual propagation is the raising of plants by means of seed which is formed due to the fusion of male and female gametes within the ovule of a flower. Plants that are produced from seeds are called seedlings. In ancient times when the asexual methods of plant propagation were not known, this was the only commercial method for plant propagation. Papaya, phalsa and mangosteen, vegetable crops and flowers are still being propagated by seed. Advantages Seedling plants are long lived, productive and have greater tolerance to adverse soil and climatic conditions and diseases. Seed propagation makes feasible to propagate plants like papaya and coconut in which asexual means of propagation is not common not possible or economical. To develop new varieties, hybrids are first raised from seed and it is essential to employ this method in such cases. (Hybrids can only be developed by sexual means) Seed propagation is only mean of diversity particularly in the selection of chance seedlings. Polyembryonic character exists in many fruit plants such as in some citrus species and some mango varieties which give rise to more than one seedling from one seed. The nucellar seedlings are true to type. Therefore, polyembryonic varieties can be propagated by seeds. Rootstocks upon which the fruit varieties are budded or grafted are mostly raised from seeds. Seedlings are cheaper and easy to raise. Easily transported to distant places e.g. seeds Does not require high technical knowledge and skilled labour. Seeds, if stored properly can be kept for longer duration /period for future use. Limitations/disadvantages Seedling plants are not true to type to the mother plants due to heterozygous nature of fruit plants. Seedling trees are not uniform in their growth, yielding capacity and fruit quality. Seedling trees have long juvenile period and take more years to bear the first crop. Seedlings become large for economic management. It is not possible to maintain the exact character of any superior selection. Seed propagation cannot be applied in many plants e.g. banana It is not possible to avail the modifying influence of rootstock on scion or scion on rootstock. Since seed-borne viruses exist in a number of fruit plants and the multiplication of such plants by seed is not recommended Sexually raised plants are generally tall and spreading type and thus are cumbersome for carrying out various management practices like pruning, spraying, harvesting etc. Seeds of many fruits are to be sown immediately after extraction from the fruits as they lose their viability very soon e.g. cashew nut, jamun, jackfruit, citrus, mango and papaya. The beneficial influences of rootstocks on scion variety cannot be exploited in sexual propagation. Seedling plants usually produce fruits inferior quality. Asexual propagation Propagation of plants through any vegetative parts is called vegetative or asexual propagation. The goal of vegetative propagation is to reproduce progeny plants identical in genotypes to a single source plant. It is independent of sexual propagation process as there is no involvement of sex organs. It takes place due to mitotic division. Mitotic division continues in shoot tip, root tip and cambium. When some portion of plant is wounded, mitotic division takes place. Under mitotic division, chromosomes divide longitudinally to form two daughter cells. This forms the basis of asexual propagation. The plants raised through asexual process are identical to mother plants. Cutting , division, layering, budding and grafting are main techniques of asexual propagation. Advantages: Vegetatively propagated plants are true to type, uniform in growth, yielding capacity and fruit quality. Asexually propagated plants have short juvenile phase and bear flowers and fruits in the early age (3-4 years) than seedling plants. The vegetatively propagated plants are smaller in stature and hence management operations like spraying, pruning and harvesting etc. become easy. Plants in which seed setting does not take place (e.g. pineapple and banana), asexual propagation serves as a substitute for sexual propagation. Using asexual methods, desirable characters of a mother plant can be perpetuated/multiplied easily. The benefits of rootstocks and scion are usually exploited through asexual propagation. Repairing of damaged portion of plant is possible through asexual propagation as incase of bridge grafting. It is possible to convert a non-productive local variety into productive improved variety by using asexual methods. Modifying influence of rootstock on scion can be profitably availed off. It is possible to regulate the tree size, fruit quality, precocity etc. according to one's requirements by using different rootstocks. Cross pollination can be effected by grafting shoots of other suitable varieties (pollinizers) on some of the branches of self-unfruitful variety. Grafting can be used to encourage healing of tree wounds caused by rodents, implements. Composite tree can be raised. One can correct to some extent the initial mistakes of planting inferior or unsuitable varieties. It is possible to grow several varieties on one plant or change variety of existing plant by top working Disadvantages Asexual propagated plants have shorter life-span. Asexual propagation restricts diversity. Sometimes asexual propagation disseminates diseases e.g. Tristeza virus in citrus. Technical skill is required. Questions 1. _________ reproduction refers to multiplication of plants by seeds A) Sexual B) Asexual C) Cutting D) Budding 2. ______ propagated plants are long lived, productive and have greater tolerance to adverse soil and climatic conditions and diseases. A) Seedling B) Cutting C) Budding D) Grafting 3. Papaya is commercially propagated by A) Cutting B) Budding C) Seed D) Grafting 4. Propagation of plants through any vegetative parts is called __________ propagation A) Asexual B) Sexual C) Apomixes D) Both A and B 5. __________ methods of propagated plants are true to type, uniform in growth, yielding capacity and fruit quality A) Seed B) Vegetatively C) Both A and B D) None of this 6. What is sexual propagation? Describe advantages and disadvantages of sexual propagation method? 7. What is Asexual propagation? Describe advantages and disadvantages of asexual propagation method? Lecture – 5. MICRO AND MEGASPORAGENESIS, APOMIXIS, MONO EMBRYONY AND POLY EMBRYONY SEXUAL PROPAGATION Sexual propagation of plants is by means of seeds. The seeds are the fertilized ovule containing embryos resulting from the union of male and female gametes during fertilization. The embryo in the seed gives rise to the new plant during germination. The development of a male and female gametes and how fertilization takes place are described below MICROSPOROGENESIS Pollen is produced in the anther. In the early stage of development, the anther consists of a small group of meristematic cells. As it matures, four groups of microspores mother cells develop with it. Each microscope mother cells divides meiotically to produce four microspores, each of which contains the haploid (n) number of chromosomes. Each microspore develops into a pollen grain after undergoing a mitotic division producing two nuclei. The two nuclei of the pollen grain are the “tube nucleus” and the “generative nucleus”. The generative nucleus subsequently divides to produce two male gametes or sperm cells before the pollen is shed. MEGASPOROGENESIS The formation of seed begins with the development of an ovule. In the young ovule, all the cells that compose the nucleus are identical. However, one of nuclear cells, usually just below the epidermis near the top, differentiates from the surrounding cells, eventually forming the embryo sac (megaspore) mother cells. Generally this is 2n or diploid tissue. The nucleus of this mother cell undergoes two successive meiotic divisions, forming a row of four cells called “megaspores”. They are genetically “n” or haploid cells. Generally, three of the four cells nearer the micropolar end disintegrate and the remaining cells develop into the mature embryo sac. The nucleus of the remaining megaspore divides meiotically thrice to form the eight nucleated mature embryo sac. Thus, each mature embryo sac contains eight nuclei (each n) consisting of one egg cell, two synergid cells, three antipodal cells and one primary endosperm cells with two nuclei. During pollination, pollen is transferred from the anther to the stigma where it germinates and grows down the style until it reaches the embryo sac. The pollen tube penetrates the tissue of the stigma, grows down the style and enters the ovary usually through the micropyle. The tip of the pollen tube then ruptures and the sperm nuclei move towards and fuse with the egg effecting fertilization and form the zygote (2n). The second sperm nucleus unites with the two polar nuclei in a double fertilization farming the primary endosperm (3n). After fertilization of the ovule, the embryo and endosperm continue to grow and differentiate, ultimately forming the seed. Usually, in the development of fruit and seed, the following relationship can be established. 1. Ovary- Fruits 2. Ovule- Seeds 3. Nucellus- Perisperm 4. Two polar nuclei + sperm nucleus – Endosperm 3n 5. Egg nucleus + sperm nucleus – Zygote- embryo (diploid 2n) The developed seed has three parts embryo, food storage tissues which may be the endosperm, the perisperm or cotyledon and seed coverings. The seeds in which the endosperm is large and contain most of the stored food are called as “ albuminous seeds”, while the seeds in which the endosperm is lacking or reduced to a thin layer surrounding the embryo are referred to as “ex albuminous seeds”. APOMIXIS: Embryos are produced not through meiosis and fertilization, but as a result of certain asexual processes are known as apomixis. The occurrence of asexual reproductive process occurs in place of normal sexual reproductive process of reduction division. The seedlings produced through such processes are called as “apomicts”. Obligate apomicts: Plants which produce only apomictic embryos are known as obligate apomicts e.g.Mangosteen Facultative apomicts: Produce which produce both apomictic and sexual embryos are known as facultative apomicts e.g. Citrus Four types of apomixs reported in horticultural crops 1. Recurrent apomixis: The embryo develops from the diploid egg cells or from the diploid cells of the embryo sac without fertilization. The egg has the normal diploid number of chromosomes as that of the mother plant. E.g. Malus, Rubus, Allium 2. Non-recurrent apomixis: The embryo develops directly from the haploid egg cell or some other haploid cells of the embryo sac and hence haploid plants are produced. E.g. Solanum nigrum and Lilium sp. 3. Nucellar embryony or adventitious embryony: The embryo arises from a cell or a group of cells either in the nucleus or in the integuments and hence they are diploid in nature having the genetic constitution of its mother plant. It differs from recurrent apomixis, as the embryos develop outside the embryo sac, besides a normal embryo develops with in the embryo sac. This can also be referred as “facultative apomixis”. E.g) Citrus (Acid lime, mandarin, sweet orange) and certain varieties of mango like olour, Bapakkai, Kurukkan. 4. Vegetative apomixis: In some species, the flowers, in an inflorescence are replaced by vegetative buds called bulbils, which sprout and produce new plants while still remain, attached on other plants. E.g. Allium sativum, Agave, Dioscorea bulbifera MONO EMBRYONY: Presence of single embryo in a seed is known as monoembryony. The embryo is formed due to the normal sexual reproductive process, as a result of fusion of egg and pollen during fertilization. The seedlings obtained from such embryos are not true to type, unless controlled pollination is attempted. E.g. All varieties of mango except certain varieties like Olour, Bapakkai, Kurukkan etc. POLYEMBRYONY It is the occurrence of more than one embryo in a seed which consequently results in the emergence of multiple seedlings. The additional embryos result from the differentiation and development of various maternal and zygotic tissues associated with the ovule of seed. Polyembryony may be classified on the basis of frequency as follows Polyembryonic - If the percent of multiple seed is more than 10% this condition is called polyembryony and plants are called polyembryonate. Strictly polyembryonic – Plant species in which the frequency of multiple embryos in less than 7% is described as strictly polyembryonic. Nearly monoembryonic – In case of nearly monoembryonic plant species the frequency of polyembryony varies between 6-10%. Gametophytic polyembryony– Multiple embryos arises from the gametic cells of the embryo sac (synergid, antipodal) after or without fertilization. In this case haploid embryos are formed. Sporophytic polyembryony - When multiple embryos arise either from zygote or from sporophytic cells of ovule (nucellus, integument) and the resulting embryo will be diploid. Hence citrus, mango and jamun exhibit true and sporophytic polyembryony. Poly embryony in Mango and Citrus Poly embryonic seedlings can be differentiated from its true seedlings by their uniformity and vigorous growth. Questions 1. Phenomenon in which two or more embryos are produced in a seed A Parthenocarpy B Parthenogenesis C Polyembryonic D Monoembryonic 2. Sexual propagation of plants is by means of ________ A Apomixis B Embryo C Seeds D Cutting 3. Presence of single embryo in a seed is known as A Polyembryony B Monoembryony C Apomixis D Seedling 4. The embryo arises from a cell or a group of cells either in the nucleus or in the integuments is called as __________ A Nucellar embryony B Gametophytic polyembryony C Sporophytic polyembryony D Vegetative apomixis 5. Plants which produce only apomictic embryos are known as A Sporophytic polyembryony B obligate apomicts C Gametophytic polyembryony D Nucellarembryony 6. Explain megasporogenesis? 7. Define apomixis Lecture – 6. SEED QUALITY, DORMANCY, TYPES OF DORMANCY, VIABILITY, GERMINATION, LONGEVITY, SEEDLING VIGOUR AND SEED INVIGORATION SEED QUALITY Seed quality describes the potential performance of a seed lot. Trueness to variety; the presence of inert matter, seed of other crops or weed seed, germination percentage, vigour, appearance, and freedom from disease are important aspects of seed quality. In horticultural crops, the seed quality determines the potential yield of the crop. SEED DORMANCY It is a condition where the seed does not germinate when sown in normal conditions. Dormancy is a condition where seeds will not germinate even when the environmental conditions such as water, temperature and air are favourable for germination. It is observed that seeds of some fruit plants (mango, citrus) germinate immediately after extraction from the fruit under favourable conditions of moisture, temperature and aeration. However, in others (apple, pear, cherry) germination does not take place even under favourable conditions. This phenomenon is called as dormancy‟. This is an important survival mechanism for some species because these species do not germinate unless adverse climatic conditions end. In some species, chilling temperature for certain period helps in the termination of dormancy. Often dormancy is due to several factors and may persist indefinitely unless certain specific treatments are given. Types of dormancy: Different types of dormancy include 1. Exogenous dormancy 2. Endogenous dormancy Exogenous dormancy This type of dormancy is imposed by factors outside the embryo. In exogenous dormancy, the tissues enclosing the embryo can affect germination by inhibiting water uptake, providing mechanical resistance to embryo expansion and radicle emergence, modifying gaseous exchange (limit oxygen to embryo), preventing leaching of inhibitor from the embryo and supplying inhibitor to the embryo. It is of three types: a) Physical dormancy (seed coat dormancy): Seed coat or seed covering may become hard, fibrous or mucilagenous (adhesives gum) during ripening as a result they become impermeable to water and gases, which prevents the physiological processes initiating germination. This type of dormancy is very common in drupe fruits i.e. olive, peach, plum, apricot ,cherry (hardened endocarp), walnut and pecan nut (surrounding shell).In various plant families, such as Leguminosae, the outer seed coat gets hardened and becomes suberized and impervious to water. b) Mechanical dormancy: In some fruits, seed covering restricts radicle growth, resulting in dormancy of seeds. Some seed covering structures, such as shells of walnut, pits of stone fruits and stones of olive are too hard to allow the dormant embryo to expand during germination. The water may be absorbed but the difficulty arises in the expansion of seed coat. Germination in such seeds does not occur until and unless the seed coats are softened either by creating moist and warm conditions during storage or by microbial activity. c) Chemical dormancy: In seeds of some fruits chemicals that accumulate in fruit and seed covering tissues during development and remain with the seed after harvest. It is quite common in fleshy harvested fruits or fruits whose seeds remain within juicy pulp as in citrus, cucurbits, stone fruits, pear, grapes and tomatoes. Some of the substances associated with inhibition are various phenols, coumarin and abscisic acid. These substances can strongly inhibit seed germination. 2. Endogenous dormancy This type of dormancy is imposed by rudimentary or undeveloped embryo at the time of ripening or maturity. This can be of different types such as morphological, physiological, double dormancy and secondary dormancy. A. Morphological dormancy (Rudimentary and linear embryo): Dormancy occurs in some seeds in which the embryo is not fully developed at the time of fruit ripening and harvest. Such seeds do not germinate, if planted immediately after harvesting. Plants with rudimentary embryos produce seeds with little more than pro-embryo embedded in a massive endosperm at the time of fruit maturation. Enlargement of the embryo occurs after the seeds have imbibed water but, before germination begins Formation of rudimentary embryo is common in various plant families such as Ranunculaceae (Ranunculus), Papavaraceae (poppy). Some plants of temperate zone like holly and snowberry have also rudimentary embryos. B. Physiological dormancy i) Non-deep physiological dormancy: After ripening time is required for seeds in dry storage to lose dormancy. This type of dormancy is often transitory and disappears during dry storage. Temperate fruits such as apple, pear, cherry, peach, plum and apricot, cultivated cereals, vegetables and flower crops, have this type of physiological dormancy which may last for one to six months and disappears with dry storage. ii) Photo dormancy: Seeds that either requires light or dark condition to germinate are termed as photo-dormant seeds. It is due to photo-chemically reactive pigment called phytochrome widely present in some plants. When imbibed seeds are exposed to red light (660-760 nm), the phytochrome changes to red form (Pfr), thereby substituting the germination process. However, when seeds are exposed to far-red light (760- 800), Pfr is changed to Pf which inhibits germination process. iii) Thermo dormancy: Some seeds have specific temperature requirement for their germination, otherwise they remain dormant. Such seeds are called as thermo dormant For example seeds of lettuce, celery and pansy do not germinate if the temperature is below 250C. C. Double dormancy Combination of two or more types of dormancy is known as „double dormancy‟. It can be morpho- physiological i.e. combination of under developed embryo and physiological dormancy or exo- endodormancy i.e. combination of exogenous and endogenous dormancy conditions i.e. hard seed coat (physical plus intermediate physiological dormancy). In some species, seeds have dormancy due to both hard seed coats and dormant embryos. For instance, some tree legumes seed coats are impervious and at the same time their embryo are also dormant. Such seeds require two years for breaking of dormancy in nature. In the first spring, the microorganisms act upon the seed making it weak and soft and then embryo dormancy is broken by chilling temperature in the winter next year. D. Secondary dormancy Secondary dormancy is due to germination conditions. It is a further adaptation to prevent germination of an imbibed seed if other environmental conditions are not favourable. These conditions can include unfavourably high or low temperature, prolonged darkness and water stress. It is of two types: i) Thermo dormancy: High temperature induced dormancy. ii) Conditional dormancy: Change in ability to germinate related to time of the year. Advantages of dormancy Permitting germination only when environmental conditions favour seedling survival as in fruit plants of temperate region. Helpful in creation of a “seed bank” Dormancy can also synchronize germination to a particular time of the year. Seed disposal can be facilitated by specialized dormancy conditions. For example modification of seed covering through digestive tract of a bird or other animals. Methods of breaking seed dormancy a. Soaking in water: This helps in better absorption of water and gases, softening of seed coat, which ultimately leads to better germination of the seeds. This can be achieved by soaking in water.soaking of seeds in the running water for 12-24 hours or placing them in water for few hours help in leaching off the inhibitors and phenolic compounds, which help in easy seed germination. b. Scarification: Scarification is the process of breaking, scratching, mechanically altering or softening the seed covering to make it permeable to water and gases. The scarification treatments include mechanical, chemical and hot water treatments. i) Mechanical scarification It is simple and effective if suitable equipment is available. Chipping hard seed coat by rubbing with sand paper, cutting with a file or cracking with a hammer are simple methods useful for small amount of relatively large seeds. For large scale, mechanical scarifies are used. Seeds can be tumbled in drums lined with sand paper or in concrete mixers containing coarse sand or gravel. The sand gravel should be of a different size than the seed to facilitate subsequent separation. Scarification should not proceed to the point at which the seeds are injured and inner parts of seed are exposed. ii) Acid scarification Dry seeds are placed in containers and covered with concentrated Sulphuric acid (H 2SO4) or HCl in the ratio of one part of seed to two parts of acid. The amount of seed treated at any time should be restricted to not more than10kg to avoid uncontrollable heating. The containers should be of glass, earthenware or wood, non- metal or plastic. The mixture should be stirred cautiously at intervals during the treatment to produce uniform results. The time may vary from 10 minutes to 6 hours depending upon the species.The seeds are washed to remove the acid. The acid treated seeds can either be planted immediately when wet or dried and stored for later planting. Large seeds of most legume species, brinjal and tomatoes are reported to respond simple sulphuric acid treatment. iii) Hot water scarification Drop the seeds into 4-5 times their volume of hot water with temperature ranging from 77 to 1000C. The seeds are immediately removed and soaked in cool water for gradually for 12 to 24 hours. Following this the unswollen seeds may be separated from the swollen seeds by suitable screens. The seed should be sown immediately after hot water treatment. iv) Warm moist scarification The seeds are placed in moist warm medium for many months to soften the seed coat and other seed coverings through microbial activity. This treatment is highly beneficial in seeds having double seed dormancy. The hard seeds are planted in summer or early fall when the soil temperature is still higher, that usually facilitates germination. For instance the stone fruit including cherry, plum ,apricot and peaches show increased germination if planted early enough in the summer or fall to provide one to two months of warm temperature prior to the onset of chilling. C. Stratification Stratification is a method of handling dormant seed in which the imbibed seeds are subjected to a period of chilling to after ripen the embryo in alternate layers of sand or soil for a specific period. It is also known as moist chilling. However, temperate species displaying epicotyl dormancy (like fringed tree) or under developed embryo (like hollies) a warm stratification of several months followed b

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