Seed Plot Technique for Potato Cultivation

• Innovative Seed Plot Technique revolutionized potato cultivation in India
• Seed Plot Technique involves producing healthy planting material in India's sub-tropical plains
• Potatoes are mostly propagated through tubers, unlike most crops that use 'true' seeds
• Vegetative propagation through tubers causes a decline in the yield potential of seed tubers over time
• Dutch farmers termed this phenomenon as ‘degeneration', 'running out' or 'senility' of potato in 1792
• Potato degeneration is more acute in sub-tropical plains
• Imported European varieties became uneconomical within 2-3 years due to degeneration in Indian plains
• Rapid degeneration prevented the development of indigenous varieties
• Breeding efforts from 1935 to 1968 were unsuccessful because of this degeneration
• Making crosses at high altitude and selection in plains became counterproductive
• Priority was given to tackling degeneration in the plains of India as of 1959
• Virus diseases infecting seed tubers are the main cause of the problem of degeneration
• Viruses are systemic and multiply within the tuber for generations
• High rate of degeneration occurred in Indian plains due to conditions being ideal for virus infection
• Seed potato was imported regularly from Italy, Kenya Colony, and Australia as a result
• Potato virus disease surveys showed that high hills in India are ideal for seed potato production
• High hills with humid climate, high wind velocity and low temperature (14-25 °C) are ideal for seed production
• Conditions in high hills do not favor multiplication and movement of aphids, the carriers of potato viruses
• Crops grown in high hills have a low incidence of aphid transmitted viruses and a slow rate of degeneration
• Locations in the high hills of Himachal Pradesh, Uttar Pradesh, Jammu and Kashmir, and North-eastern hills became seed production focal points
• Seed production in hills could not sustain potato cultivation in India
• 2.5 to 4 metric tonnes of seed potatoes are needed to plant one hectare
• A need to have a technology for producing healthy seed potatoes in the Indo-Gangetic plains was identified
• Maintaining seed potatoes in a healthy state in the plains of India was suggested in 1959
• The 'Seed Plot Technique' is based on understanding the population dynamics of the virus vector
• Aphids are either absent or very low in the North Indian plains (Indo-Gangetic plains) from October to December
• October to December is long enough to grow a healthy seed crop
• First pilot experiment was undertaken in Jalandhar at the farm of Mr. Iqbal Singh Dhillon
• The plains of India became the most favorable place for the production and propagation of healthy seed potatoes
• Seed stocks are healthier than those produced in Europe
• The innovation of the 'Seed Plot Technique' is credited to Dr. Pushkarnath and his colleagues
• Dr. Pushkarnath was awarded the Rafi Ahmed Kidwai award of ICAR in 1963 for this unique contribution

Technology Details

• The ‘Seed Plot Technique’ is based on a low aphid period of at least 70-75 days for growing seed crop
• The following is needed for Seed Plot Technique success
  • the soil should be free from soil-borne pathogens like wart, cyst nematodes, bacterial wilt, black scurf, and common scab
  • there should be a low aphid or aphid free period of 70-75 days after planting the crop
  • the minimum and maximum temperature should be 8-28 °C during crop season
  • the varieties used should have a slow rate of degeneration
• 'Seed Plot Technique' was restricted to Punjab initially
  • comprised planting of seed crop during September end to mid-October
  • planting at a close spacing in not too rich a soil to ensure large percentage of seed-sized tubers
  • crops undergo two inspections to remove off-types and virus infected plants
  • Irrigation is restricted from mid-December onwards
  • Dehaulming occurs at the end of December or when the critical level of 20 aphids/100 compound leaves are observed
• Self-set plants from left over tubers in the fields serve as the spread of virus diseases
• The seed produced under low aphid period developed more sprouts as a result of good physical condition of tubers
  • good physical condition is from 6-7 months storage at low temperature (2-3°C) as compared to traditionally grown hill seed
• Various virus diseases were less than 1.5% after 3 to 4 years of propagation in Jalandhar
• The technique was refined, considering aphid appearance and subsequent buildup from the Indo-Gangetic plains' regions
• Systemic insecticides are useful in controlling vectors
  • Systemic insecticides can be used in areas where aphids appear early during crop growth period, such as Madhya Pradesh, Gujarat and Maharashtra
  • Systemic insecticides allow for good quality seed production in these regions
• Agrotechniques for seed production by the ‘Seed Plot Technique’ were standardized and refined continuously

Agrotechniques for seed production

• Soil should be free from perennial weeds and soil-borne pathogens

  • scabs, brown rot, wart and black scurf and pest like cut worm (Agrotis ipsilon)

• 2-3 years’ crop rotation is desirable to minimize the perpetuation of soil-borne diseases preferably with cereals, and should not have been grown for the last two years

• The soil preferred is a light textured sandy loam with neutral to slightly alkaline soil pH

• Opening the soil with deep tillage and exposure to high temperatures during hot summers reduces soil-borne diseases

• Soil Solarisation uses black plastic mulch for 60 days to destroys pests to improve soil properties

• 45-55 days old green manure crops of sunhemp or dhaincha are used during rainy season

  • Improves soil fertility and water holding capacity
  • Reduce pest and disease incidence

• Potato seed production demands minimal mechanical interference

  • Field should be cleaned of stubble and weeds prior to planting
  • Apply minimum tillage to save on the fuel, time and money to reduce cost of cultivation
  • Minimum tillage combined with chemical weed control is best suited for seed production as it ensures minimum interference in standing crop

• The seed crop is separated from crops meant for "ware' purpose by a distance of at least 25 meters to avoid mixture and spread of viral diseases

• Isolation distance of 05 meters is also needed between different varieties of the seed crop

• Farmers need healthy, disease-free, and quality true-to-type seed from a reliable source

• Use foundation or certified seed tubers to start with and replace every 3-4 years

• Pre-sprouting ensures growth of multiple, stout and healthy sprouts

  • Helps in quick emergence, uniform stand and early maturity of the crop
  • Helps improves yield, number of tubers and proportion of seed-sized tubers in the produce

• Withdraw seed tubers from cold store 10-15 days before planting

• Remove sprouts if tubers are already over-sprouted

  • To check apical dominance

• Blind tubers, hairy sprouted, rotten and diseased tubers should be sorted out

• Seed tubers should be moved with care to avoid damage to the sprouts

• Temperature can be between 30-32°C (max) and 18-20°C (min) at planting Time

• In seed crop, the aphid free period of growth is also important

  • Planting must be completed in a time schedule to ensure 75-85 days of low aphid period for crop growth.

• Optimum planting time:

  • first week of October (North-western plains)
  • second to third week of October (West-central plains and eastern plains)
  • last week of October and first week of November (Western MP)

• Use only whole tubers at spacing according to size for seed crop

• A plant population of about 1 to 1.1 lakhs hills/ha provides best results

• Use the following planting distances:

  • 40-45 cm inter-row spacing for planting seed crop manually
  • 50-55 cm inter-row spacing bullock implement
  • 60 cm inter-row spacing tractor drawn implements

• 30-40 g seed-sized tubers at 60 cm inter and 20 cm intra-row spacing is best for seed potato production

• The objective is to keep the seed rate reasonably within limits (32-35 q/ha)

• Plant the large size tubers by increasing the intra-row spacing from 20 to 30 cm depending upon the size of seed tubers

• Small-sized tubers are planted at reduced intra-row spacing

• Seed tubers are placed at a depth of 5-7 cm from top of the ridges made manually or by tractor drawn implements

• Farmyard manure and vermicompost is beneficial for seed crop

  • Improves physical, chemical and biological condition, soil fertility and water holding capacity

• Incoroporate manure prior to planting (20-25 days)

• The amount of N needed is 25-30% lower than that of other crops

• The crop requires a basal dose of 75 kg N, 60-80 kg P2O5 and 100-120 kg K2O/ha at planting

  • A split dose of 75 kg N/ha given through urea is adequate

• If seed crop is grown under drip irrigation, nutrient dose should be reduced by 25%

• Plant viruses should be minimum

  • Operations involving human, animal and implement movement in standing seed crop should be minimal to prevent transmission of plant viruses through physical contact
  • Better to complete such operations prior to attainng height of about 10-15 cm

• Apply Nitrogen with thimet at hoeing with earthing up up about 5 cm away from the plants before 30 days after planting

• Pr-emergence treatments are also available to control weeds

• Apply Metribuzin and herbicides in moist soil after planting

• Apply Paraquat after enough weeds have appeared for killing

  • Avoid using Metribuzin with sensitive potato varieties

• Presowing irrigation is beneficial for uniform emergence

• Give crop first irrigation following planting for ridges to form

• Water at 7-10 day intervals without flooding

• Excess moisture can cause the seed to rupture

• The moisture stress can be helpful for havest and curing

• Irrigation not required 10 days before hauleming if the oil is fertile

• Additional protections are needed in seed crops against aphids

• Apply granular systemic insecticide at planting and earthing up

• Aphids: Apply sprays of Imidacloprid or Thiamethoxam can be repeated in intervals

• Alternate sprays of these chemicals to protect insects from the insecticide

• Drench Ridges with Chloropyriphos for cut work attack in early stages

• In case control of early blight give Mancozeb prophylatic spray , also good for fungal diseases

• Give systemic gunguses and repeat spray from intervals of 7-10 days

• The followinf off types of diseases have to be inspected and removed:

  • mosaic, mottling, veinal necrosis, crinkling ,rolling and purple top

• Roguing should take place at 45 ,60 and 80 days after planting

• Make sure to remove all the tubers or rogued plants

• When you remove haulms it should be removed by Janruary When population of aphid are at 20 on compound crop and area

• Cut them manully pull or spray perquat

• Protect haums from climate

• Dehaulm tender leaves

• Dig up gangetics completely by Fevruary

• Remove and rotate material

• Let it set for week or so

• Get tubers and set for about 15 days

• For 1.5 m wide with 3.5 m land

• Grade produces for seed market

Proper Sice and Treamtment

• Borid Aid for surface scab

• Emissian is also effecitive but hazardous

• Store at 4°C late Feb in bags

• Important charecteristics of technique adoption after proper crop for pathogens

• Isolation after meters The Stocks after diagnoistics are disease free

• USe col store proper seed

• Time seed is correct Treat for herbiage

• Kill vectors 10 days prior to jan

Adoption and Impact

• Production was responsible to area amount

• Increase of 62 percent

• High seed and breed for varieties

• Led to expansion

• Production shifted from hills to plaind

• Higher yiels

• Reduced export for other disease

• Lead to develpment

• Improvwed varieties included:

  • Kufri Chandramukhi, Kufri Bahar, Kufri Jyoti, Kufri Badshah, Kufri Sindhuri and Kufri Lalima

• Elimination of imports and valuble sources