Detection of QTL for Cold Tolerance at Bud Bursting Stage Using Chromosome Segment Substitution Lines in Rice (Oryza sativa)

The cold tolerance at the bud bursting stage (CTB) was evaluated at 5 degrees C by using a set of 95 chromosome segment substitution lines (CSSLs) derived from an indica rice 9311 and a japonica rice Nipponbare with a genetic background of 9311. The result showed that six CSSLs had slightly stronger effect on CTB than 9311. Total four quantitative trait loci (QTLs) for CTB were preliminary mapped on chromosomes 5 and 7 by substitution mapping. qCTB-5-1, qCTB-5-2 and qCTB-5-3 were mapped in the region of RM267-RM1237, RM2422-RM6054 and RM3321-RM1054, which were 21.3 cM, 27.4 cM and 12.7 cM in genetic distance on rice chromosome 5, respectively. qCTB-7 was mapped in a 6.8-cM region of RM11-RM2752 on rice chromosome 7.