Plant Breeding Introduction & Reproduction PDF

# Agriculture Padhai Online Classes [APOC] ## First Edition ### Plant Breeding-1 Plant breeding is an art and science, which tells us ways and means to change the genetic architecture of plants so as to attain a particular objective. ### Objectives of Plant Breeding - Increased yield - Improv...

# Agriculture Padhai Online Classes [APOC] ## First Edition ### Plant Breeding-1 Plant breeding is an art and science, which tells us ways and means to change the genetic architecture of plants so as to attain a particular objective. ### Objectives of Plant Breeding - Increased yield - Improving the quality - Elimination of toxic substance - Resistance against biotic and abiotic stresses - Change in maturity duration – Evolution of early maturing varieties - Improved agronomic characters -Production of more tillers - E.g. Rice, Bajra, - Reducing the plant height to prevent lodging Rice - Photoinsensitivity - Redgram, sorghum - Non-shattering nature - Green gram, Brassicas - Synchronized maturity - Pulses - Determinate Growth habit-determinate growth - Pulses - Elimination or introduction of dormancy -Groundnut ### History of Plant Breeding | Year | Contribution | Contribution | |---|---|---| | 1717 | Thomas Fairchild | Produced the first artificial hybrid between sweet william And carnation species of Dianthus | | 1857 | Vilmorin | Proposed individual plant selection based on progeny testing. This was known as "vilmorins principle of progeny testing'. | | 1890 | Rimpu | Made first inter -generic cross between bread wheat (T. Aestivum) and rye (Secale cereal) to give birth of Triticale. DT -46 is the variety of triticale | | 1903 | Johansen | Proposed the famous 'pure line theory' which states that a pure line is progeny of a single self fertilized homozygous plant. He proposed this theory based on his studies in Phaseolus vulgaris. | | 1917 | Jones, D.F. | Made double cross in maize | | 1917 | Vavilon, N.I. | Used genetic male sterility in the development of maize hybrid. The center of origin given by: Vavilon Identify 8 main centers and 3 sub centers of crop diversity.| | 1935 | Nagaharu, U | Tetraploids species of Brassica using a triangle which is Popularly known as U's triangle. | | 1937 | Harrington, J.B. | Proposed mass pedigree method of breeding which is a Modification of pedigree method | | 1956 | Flor, H. H. | He developed the concept of gene for gene hypothesis in flax for flax rust caused by Malampsora lint. | | 1963 | Vander Plank, J. E. | Developed the concept of vertical and horizontal resistance. | | 1968 | Donald, C.M. | Crop Ideotype working with wheat. | | 1968 | G.H. Shull | Work in maize is the forerunner for the present day hybrid maize programme. He described in detail about the effect of inbreeding.| ### Modes of Reproduction - **Sexual reproduction** Multiplication of plants through embryos which have developed by fusion of male and female gametes is known as sexual reproduction. Ex Seed - **Sporogenesis** Production of microspores and megaspores is known as sporogenesis. - **Microsporogenesis** The sporophytic cells in the pollen sacs of anther which undergo meiotic division to form haploid i.e., microspores are called microspore (MMC) or pollen mother cell (PMC) and the process is called microsporogenesis. - **Megasporogenesis** A single sporophytic cell inside the ovule, which undergo meiotic division to form haploid megaspore, is called megaspore mother cell (MMC) and the process is called megasporogenesis - **Gametogenesis** The production of male and female gametes in the microspores and megaspores is knownas gametogenesis. - **Megagametogenesis** The development of embryo sac from a megaspore is known as megagametogeneis. - **Microgametogenesis** The pollen along with the pollen tube possessing a pair of sperm nuclei is called microgametophyte. - **Fertilization** The fusion of one of the two sperms with the egg cell producing a diploid zygote is known as fertilization. - **Asexual reproduction** Multiplication of plants without the fusion of male and female gametes is known as asexual reproduction. - **Thus asexual reproduction is of two types: and** - **Vegetative reproduction** - **Natural vegetative reproduction** - Rhizome - Turmeric (Curcuma domestica), Ginger (Zingiber officinale) - Tuber - Potato (Solanum tuberosum) - Corm - Arvi (Colocasia esculenta), Bunda (C. antiquorum) - Bulb - Garlic (Allium sativum), onion (A. cepa) - **Artificial vegetative reproduction** - Stem cuttings - Sugarcane (Saccharum sp.) grapes (Vitis vinifera), roses, etc. - Root cuttings - Sweet potato, citrus, lemon, etc. Layering and grafting are use fruit ornamental crops. - **Apomixis** - Apomixis refers to the development of seed without sexual fusion (fertilization). - In apomixis embryo develops without fertilization. - **There are four types of apomixis:** - Parthenogenesis - Apogamy - Apospory - Adventive embryony - **Parthenogenesis** Parthenogenesis refers to development of embryo from the egg cell without fertilization. - **Apogamy** The origin of embryo from either synergids or antipodal cells of the embryosac is called as apogamy. - **Apospory** In apospory, first diploid cell of ovule lying outside the embryosac develops into another embryosac without reduction. - **Adventive embryony** The development of embryo directly from the diploid cells of ovule lying outside the embryosac belonging to either nucellus or integuments is referred to as adventive embryony. The document describes plant breeding, its objectives, and the history of plant breeding. It goes on to explain the different modes of reproduction in plants, including sexual and asexual reproduction. Finally, it details the different types of apomixis, a form of asexual reproduction.