Seed Production of Vegetable, Tuber and Spice Crops (2+1)

Hybrid seed production

1.Manual emasculation and pollination

• Initially the method was adopted for producing F1 hybrids.
• Since much labour is involved, which results in lesser quantity of seed and escalades production cost.
  
• Hence, it is not practicable on commercial scale.
2.Hand pollination without emasculation

• Where male sterility is available, the process of emasculation is eliminated.
  
• Male sterility is the absence of non-function of pollen in platns, which can be used for commercial hybrid seed production.
• In cole crops, male sterility is controlled plants by a single recessive gene ms which is mutated from the fertile gene Ms.
  
• Male sterile plants are female fertile but their flowers and anthers are slightly smaller than those of male fertile one.
3.Cytoplasmic male sterility

• Cytoplasmic male sterility has not apparently been found in cauliflower, but it has been introduced from several sources. Pearson crossed Brassica oleracea with Brassica nigra and derived male sterile material. This character was bred into broccoli and later into cauliflower.
4.Free insect pollination

• Free insect pollination is feasible to produce F1 hybrids under natural conditions.
  
• But this can only be used when self incompatible lines are available.
5.Self Incompatibility

• It is genetically controlled physiological hinderance to self-fruitfulness or self fertilization.
  
• Cauliflower, broccoli and other Brassica vegetables posses homomorphic sporophytic incompatability controlled by one locus with multiple alleles.
  
• The sporophytic system, which operates in these crops, are utilized in making single, double and triple cross hybrids for commercial seed production. Production of hybrid seed involves.
1. Selection of parents development of homozygous self-incompatible lines by inbreeding and their maintenance.
2. Making diallel or top crosses using these incompatible lines
3. Testing of F1 hybrids in replicated trials along with parents and check cultivars
4. Production of F1 hybrid seed of the recommended F1 hybrid using self- incompatible under local conditions.