MSc

An experiment titled ‘Optimizing planting time, seed extraction and seed storage in oriental pickling melon (Cucumis melo var. conomon Mak.)’, was conducted in the Department of Seed Science and Technology, using variety ‘Saubhagya’ with the objective to ascertain the optimum time of sowing to maximize seed yield, and to standardize the seed extraction method and seed storage conditions.
Sowing was taken up at monthly intervals starting from August’16 up to February’17 to ascertain the optimum time of sowing. Results indicated that crops raised in the months of August and September recorded higher seed yield and yield related parameters like fruit length, fruit diameter, fruit weight, fruit yield per vine, number of seeds per fruit, fresh weight and dry weight of seeds per fruit. Early emergence of female flower was observed in crops sown in the months of December, January and February. Vivipary was also seen in December (6.54 %), January (5.34 %) and February (4.70 %) months of sowing. The study suggests August sowing as the ideal time for seed production as yield attributes like fruit length, fruit diameter, fruit weight, fruit yield per vine, number of seeds per fruit, fresh weight and dry weight of seeds per fruit were high.
Seed extraction influences the seed quality and its storability. A crop was raised in June 2016 and fruits harvested from the crop was used for extraction. Various methods of seed extraction were employed viz., hand extraction method, fermentation and acid (HCl) extraction method (various concentration and exposure time). Examination of quality parameters of the freshly extracted seeds revealed that extraction with conc. HCl 25 ml/ 1.5 litre of water for 30 minutes recorded the highest germination per cent, vigour indices and other quality parameters. Acid seed extraction may be recommended when immediate sowing is required.
The extracted seeds were dried to less than 8 per cent moisture and packed in polyethylene covers of 700G and stored under cold and ambient conditions for a period of eight months. Observations on seed quality parameters were recorded at monthly intervals. Irrespective of the extraction methods followed, a higher germination and seedling vigour coupled with a significant reduction in mean germination time, time taken for 50 per cent germination and electrical conductivity of seed leachates was observed in seeds stored under cold storage compared to seeds stored under ambient conditions.
Seed extraction through fermentation method recorded the highest germination, shoot length, root length and seedling vigour indices under both storage conditions followed by hand extraction method. Under ambient conditions, seeds extracted from fermentation method sustained germination above Indian minimum seed certification standards (MSCS) which is 60% for a period of four months. Under cold storage, seeds extracted by fermentation method maintained MSCS till the end of the storage period (8 MAS) while in other treatments it was maintained only for 5 MAS. Over the storage period the value of electrical conductivity of seed leachates, mean germination time and time taken for 50 per cent germination was least in fermentation method indicating early emergence and better field stand. Freshly extracted seeds were devoid of seed microflora infection. However, at the end of the storage period microflora infection was highest in hand extraction and lowest in acid treatments. The organisms observed were Aspergillus niger and A. flavus
From the study it can be concluded that seed storage under cold conditions is beneficial for prolonging the seed longevity. Fermentation and hand extraction of seeds is advisable to retain the seed quality and prolong seed viability during storage.