Seed Health Management for Better Productivity - Govind Ballabh ...

(Seed Health Management for Better Productivity)agronomic practices should be followed to provide conditions for optimal growth and developmentof plant and seeds, which favour production of healthy and vigorous seed. Clean cultivation withproper weed control during seed production makes subsequent cleaning and grading easier.Phosphate and potassium fertilizers are generally more important for seed crops than forcommercial crops and their recommended doses must be applied.9. RoguingRoguing is the removal of Off-type plants. It is an important aspect of seed production tomaintain varietal purity. Any plant which does not conform to the characteristics of the variety iscalled an Off-type. Off-types are generally considered to arise from segregation of residualheterozygosity, out-crossing with varieties, admixtures or natural mutations. Off-types could bedistinct from plants of variety with reference to any character such as plant height, days toflowering, waxiness, pigmentation, ear shape, ear size, ear density, ear colour etc. It is essentialthat Off-types are removed before they flower, particularly in cross-pollinated crops, to avoidcontamination by pollen from Off-type plants. Roguing may need to be carried out several timesduring the crop season. Composite, synthetic and open pollinated varieties of cross-pollinatedcrops generally have broad genetic base and some amount of variability is inevitable. Roguing insuch varieties should not be very rigid so that the varietal gene pool is not disturbed. Only obviousOff-types and diseased plants etc. should be removed.In addition to roguing, all plants that do not conform to the varietal descriptors, inseparableother crops plants, objectionable weeds as well as plants infected with seed-borne diseasesshould also be removed. As a general rule, the Off-types should be removed and taken away fromthe seed production plot and destroyed. The back of the person doing roguing should face sun tofacilitates easier detection of Off-types.In hybrid seed production, some additional operations may be required such asdetasselling in the seed parent rows in maize and removal of pollen shedders from the male-sterilerows in pearls millet, sorghum, sunflower and rice. During flowering period, pollen shedders mustbe removed daily early in the morning before they shed pollen. Certain special techniques likespraying of GA 3 and rope pulling are required in hybrid rice seed production. Supplementarypollination in hybrid seed production of sunflower by putting beehives in close proximity of seedcrop ensure good seed set.10. Inspection of Seed Plots by Certification Agency OfficialsThe production of foundation and certified seed is supervised and approved by the StateSeed Certification Agency. The seed production plots are inspected by the certification staff. Thenumber of inspections vary from a minimum of 2-4. Those plots which conform to field standardsof certification are approved. Breeder seed has been kept out of the purview of certification agencyas it is not meant for public sale. Moreover, its production is done under the direct supervision ofqualified plant breeder. However, breeder seed crop is monitored by a joint inspection team ofplant breeders and officials of State Seed Certification Agency and National Seeds Corporation.11. HarvestingAfter the seed field is approved for field standards, seed crop should be harvested at a timethat will ensure maximum yield and best quality seed. The moisture content is good indicator of the- 108 -