Low Temperature Tolerance of Parental,Inbred and Hybrid Lines of Brassica Napus at Germination Stage

In order to screen rapeseed accessions with low temperature tolerance in triple cropping area,comprehensive membership function method was used to evaluate the low temperature tolerance of 176 accessions including inbred and hybrid lines of Brassica napus with germination rate,germination energy,germination index and average germination time as indicators.The results showed that 103 accessions with strong low temperature tolerance and 27 accessions with sensitive to low temperature stress were identified.The low temperature tolerance was significant different among accessions(P<0.001)while insignificantly different among different types(sterile lines,maintainer lines,restorer lines,and hybrid lines,P=0.07).The integrated membership function value was significantly correlated with germination rate,germination index and average germination time,which provided valuable information for the future breeding of low temperature tolerant varieties,especially in the middle reaches of the Yangtze River basin.