Abstract

Background: Rice seed dormancy is a problem for farmers because it affects rapid, uniform seed germination and vigor during the early stages of crop growth resulting in reducing productivity. The objective of this study was to determine the optimum heating temperature and time for breaking seed dormancy of rice seed variety RD79. Methods: The study was arranged as a factorial experiment in a completely randomized design with 2 factors. The 1st factor was a heating temperature at 52 and 54?C and the 2nd factor was a heating date with 5, 6, 7, 8, 9 and 10 days. Result: The results found that rice seeds heated with different temperatures and times showed significant difference in germination percentage, soil emergence, mean germination time, shoot length, root length, dry weight and accelerated ageing. The correlation showed that the highest correlation coefficients were observed between germination percentage and soil emergence, accelerated ageing and mean germination time and accelerated ageing and soil emergence. The principal component analysis revealed that seeds heated at 54?C for 7, 8 and 9 days dominated in germination percentage, soil emergence and accelerated ageing. Hence, the suitable condition for breaking seed dormancy of RD79 is heating at 54?C for 7 days.