Influence of Seed Storage and Priming on Naturally Aged Seeds of Aromatic Joha Rice

Joha is a fine grain aromatic rice of Assam, well known in the world market. This rice is protected and tagged as a geographical indication. This study evaluated priming effects on naturally aged seeds of two varieties, Kon Joha and Keteki Joha, after 0, 3, 6 and nine months of storage under ambient conditions. Seeds were hydro-primed, osmo-primed with 5% and 10% PEG, halo primed with 1% and 2% KCl and primed with 5 ppm and 10 ppm GA3 for 12 and 24 hours. Seed moisture percentage, germination percentage, germination index, mean germination time, seedling length and dry weight, seed vigour index, field emergence, seed reserve utilization rate, seed reserve use efficiency, seed reserve depletion percentage, and biochemical parameters like electrical conductivity, lipid peroxidation and ?-amylase were observed. Seed quality was gradually deteriorating due to ageing over the storage period. The rate of deterioration was faster for seedling vigour traits than germination parameters. There was a varietal difference in the rate of deterioration; it was slower in Kon Joha, an indigenous variety which also showed dormancy. The priming treatments were able to ameliorate the effect of seed ageing on seed germination, seedling growth and biochemical parameters in Kon Joha. Treatments with 1% KCl, 10 ppm GA3 and 5% PEG enhanced the germination parameters and vigour indicators. KCl (1%) priming was the best priming agent; 24 hours of priming for all agents was better than 12 hours.