Midstorage seed invigoration to enhance seed viability and longevity in rice (Oryza sativa L.)

Abstract

The present investigation entitled storage seed invigoration to enhance seed viability and longevity in Rice (Oryza sativa L was carried out at the Regional Agricultural Research Station (RARS) Pattambi, Kerala. The study aimed to assess the effect of seed treatments on seed quality parameters and seed microflora of paddy seeds variety Jyothi under ambient condition and low temperature condition during the storage period. This study consisted of two experiments: Effect of mid storage correction in paddy seeds stored under ambient conditions was studied in the first experiment. It was evaluated by using a Completely Randomized design (CRD) with ten treatments including control with three replications. Six and eight months old of Jyothi variety were subjected to the treatments including Control, T2: Hydration - dehydration treatment, T3: Ascorbic acid, T4: Calcium chloride, T5: Albizzia leaf powder, T6: Neem cake, T7: Neem leaf powder, T8: Neem oil, T9: Red chilli powder and T10: Vayambu leaf powder. Seeds packed in gunny bags were stored under ambient conditions. Observations were recorded on seed quality parameters, seedling parameters and seed microflora. The results revealed that the performance of treated seeds including viability and vigour were better compared to the control. A significant effect was observed in seeds treated with neem oil, hydration dehydration and red chilli powder irrespective of the age of the seeds. Neem oil treatment recorded better germination per cent (93.25%), seed vigour index (2694), less moisture content (10.76%), dehydrogenase activity (0.792 OD value), -amylase activity (2.56 mg maltose/min), protease activity (2.43 OD Value), plant height (78.40cm), number of tillers (11.66) and less seed microflora infection per cent (8.00%). Hydration dehydration treatment recorded better performance in shoot length (11.24cm), root length (17.55cm), seedling dry weight (0.19g), seed vigour index (2684), electrical conductivity (0.637 dSm-1), mean germination time (4.07 days), time taken for 50% germination (3.5days) and number of tillers (11.33). Effect of mid storage correction in paddy stored under low temperature condition (4-5 °C) was evaluated in a completely randomized design with three replications in the second experiment. Six, eight and ten-month-old seeds were used. Seed treatments, sample size and packaging of seeds were as in the experiment I. The treated seeds were then stored under low-temperature condition (4-5°C). Observations were recorded on seed quality parameters, seedling quality parameters and seed microflora during storage. It was observed that seed treatments and lowtemperature condition helped to improve the seed quality compared to control. Under low temperature conditions the ten-month-old treated seeds found to have extended viability and vigour over control. A significant effect was observed in seeds treated with Neem oil, hydration dehydration treatment and red chilli powder irrespective of the age of seeds. Neem oil treatment recorded better germination per cent (94.75%), seed vigour index (2739), less moisture content (10.76%), dehydrogenase activity (0.789 OD value), -amylase activity (2.58 mg maltose/min), protease activity (2.44 OD Value), plant height (78.66cm), number. of tillers (11.66) and less seed microflora infection per cent (8.00%). Hydration dehydration treatment recorded better performance in seedling shoot length (11.29cm), seedling root length (11.60cm), seedling dry weight (0.25g), seed vigour indices (2730), electrical conductivity (0.582 dSm-1), mean germination time (4.01 days), time taken for 50% germination (2.77 days) and number of tillers (11.33). Among all the treatments seeds treated with neem oil, hydration and dehydration and red chilli powder had given better performance compared to control in improvement in seed quality parameters. Low storage condition extended the storability of the seed in terms of quality parameters to two additional months compared to ambient condition.