The quantitative trait loci (QTLs) for cold tolerance at the budburst period (CTBP) was identified using a F2:3 population including 200 lines derived from a cross of indica and japonica Milyang 23/Jileng 1. A molecular linkage map of 97 SSR markers was constructed using interval mapping and covered a total length of 1 357.3 cM with an average distance of 13.99 cM, between adjacent markers in rice genome. The CTBP of F3 lines was evaluated at 5℃, and the survival seedling rate after treating under low temperature at the budburst period was used as cold tolerance index for CTBP. A continuous distribution near to normal for CTBP was observed in F3 lines, CTBP is a quantitative trait which was controlled by some genes. Three QTLs on chromosomes 2, 4 and 7 which are associated with CTBP were detected on location of RM6-RM240, RM273-RM303, RM214-RM11, respectively, which explained the range of the observed phenotypic variance from 11.5 to 20.5%. qCTBP4 detected on RM273-RM303 of chromosome 4 explained 20.5% of the observed phenotypic variance. The effect of qCTBP4’s allelic gene comes from Jileng 1., MSc;
The culm length, panicle length, spikelets per panicle and panicle exsertion were evaluated by using F2:3 populationincluding 200 lines derived from the cross of indica and japonica Milyang 23/Jileng 1 under five different environments ofBeijing (natural normal growing environment), Kunming (natural cold environment), Gongzhuling of China (cold waterirrigation) and Chuncheon of Korea (natural normal growing environment and cold water irrigation), and QTLs of thesetraits were analyzed by using SSR markers. The results showed that 44 QTLs related to these agronomic traits weredetected under five different growing environments, and these QTLs have been located on 11 chromosomes exceptchromosome 9. The QTLs for qCL1a, qCL1b, qCL5a, qCL6b, qPL1a, qPL3a, qPL6b, qPL6c, qPL7b, qSP8b, qSP1c,qSP11a, qSP12, and qPE1 have been detected under more than two growing environments, and those that were littleaffected by environments, were stable QTLs. Among them, qCL1a, qCL1b, qPL1a, qSP1c, and qPE1 explained 24.2-55.2%,22.7-39.9%, 12.5-27.7%, 14.4-33.5%, and 26.6-28.7% of observed phynotypic variation, respectively, which were majorgenes mainly appearing as overdominance. These QTLs cause the increase in action to culm length, panicle length,spikelets per panicle, and panicle exsertion under cold environment, showing that these QTLs were correlated with coldtolerance.
HAN Long-zhiQIAO Yong-liZHANG San-yuanCAO Gui-lanYE Chang-rongXU Fu-rongDAI Lu-yuanYeJong-dooKoh Hee-jong
