Genotype differences of seed viability in rapeseed during storage at different temperature.

Commercial varieties of rapeseed need to survive hot summer from harvest to next planting in Yangtze River area - the main production area of China.Therefore retaining seed viability is important.Genotype effect on seed storage was shown to be crucial apart from environmental factors as low moisture and low temperature.In present study,germination rate was used to evaluate seed viability.40 genotypes of Brassica napus,Brassica juncea and Brassica rapa were tested at temperature of -20℃,4℃,25℃,37℃,60℃ for 3 months,6 months and 12 months,respectively.Results showed that germination rate did not change significantly at low temperature of -20℃ and 4℃.But it declined slightly with storage time at temperature of 25℃,37℃ and 60℃.So the seed viability at high temperature of 60℃ was chosen to be a criterion for evaluating the storage resistant genotype.The criterion was used to screen materials from B.campestris,B.rapa and B.juncea.Excellent germplasms with slow declining in seed viability were found in this study.They showed potential on heat-storage resistant breeding and on preserving seed viability in production.