Standardization of hybrid seed production techniques

The present investigation was undertaken to standardize appropriate hybrid seed production techniques using two parental lines, Kalyanpur Sona (male) and PBIG-4 (Female) and assessment of different quality parameters. Hybrid seeds were produced by four different methods, viz., hand pollination, insect pollination under cage, isolation planting with natural pollination and without pollinator under cage. The evaluation was done during summer 2004 and 2005 for fifteen horticultural traits namely, days to 1st male and female flower, number of primary branches per plant, days to 1st harvest, main vine length, number of fruits/plant, average fruit weight, fruit length, fruit diameter, seed cavity, fruit weight/plant, number of seeds/fruit, weight of seeds/fruit, seed yield/plant and fruit setting percentage. In addition to this, a series of laboratory tests were also conducted involving eight genotypes, viz., PBIG-1, PBIG-2, PBIG-3, PBIG-4, PBIG-44, PBIG-56, Kalyanpur Sona and DVTG-1 to determine the effect of abiotic stresses (moisture and salt) and storage (storage container and time of storage) on seed quality parameters. Further, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was also performed on two parental lines and F1 hybrid seeds produced through different mechanisms. In field experiments, significant variation was noted for all the characters except days to 1st male and female flower, number of primary branches and seed cavity. Out of four different methods, insect pollinator under cage method was found superior for fruit characters like fruit length (19.50cm and 20cm), fruit diameter (4.96cm and 4.30cm), fruit weight (76.3g and 73.3g), number of fruits/plant (28.6 and 25.3), fruit yield/plant (1.96kg and 1.69kg), number of seeds/fruit (20.20 and 19.40), seed weight/fruit (3.25g and 3.09g), seed yield/plant (92.1g and 78.1g) and fruit setting percentage (84.0% and 85.33%). Appropriate pollination time period for maximum fruit setting was standardized and noticed that from 6-7.30 AM (78.96%) and 7.30-8.30 AM (75.89 %) were found best time interval for hybrid seed production thorough hand pollination. Under moisture stress and salt stress test, it was found that germination percent, seedling length and vigour index decreased significantly as level of stress increased. The genotypes, PBIG-2, PBIG-4, PBIG-56 and Kalyanpur Sona performed well at –10 bar water potential where as under in salt stress, at 700mM NaCl concentration the best genotypes were PBIG-2, PBIG-56, PBIG-1, and Kalyanpur Sona for germination per cent, seedling length and vigour index. In seed storage experiment, germination percent, seedling length and vigour index in all the genotypes decreased with duration of time, but alluminium foil storage and polybag storage were observed to be good to maintain germination percent (84.82% and 83.87%) seedling length (15.17 cm and 14.32 cm) and vigour index (1289.44 and 1202.75) even after 11 months of storage. For all the seed quality traits, the genotypes PBIG-2, Kalyanpur Sona, PBIG-56 and PBIG-1 performed best in both the years. A total of 17 bands were detected in two parental lines and the F1 hybrid. The parental lines and F1 hybrid could be distinguished on the basis of their banding pattern. But the banding pattern was observed to be similar for parental lines and F1 hybrid produced through different mechanisms.