Variation in seed longevity of rice cultivars belonging to different isozyme groups

Abstract

The storage potential of seeds harvested at different stages of maturity was studied in ten cultivars of Oryza sativa, representing six known isozyme groups, and in two cultivars of O. glaberrima. Mass maturity (the end of the seed-filling period) was attained between 14.2 and 20.2 days after anthesis (DAA). A comparison of the estimates of p 50 (time in storage for viability to decline to 50%) of seeds harvested at 21, 28 and 35 DAA and stored at 35°C with 15% moisture content showed that maximum longevity was attained between 28 and 35 DAA in most cultivars. Cultivars belonging to isozyme group II survived longer than other cultivars with estimates of p 50 nearly doubled. On the other hand, the floating rices of Group IV had shorter longevity. Within group VI, the upland cultivar survived longer than the lowland cultivar. Both O. glaberrima cultivars survived reasonably well, showing that African rice cultivars also differ in longevity.