Identification Of QTLs Controlling Cold Tolerance Of RIL Population At Booting Stage Derived From Yunnan Landrace Rice Kunmingxiaobaigu

Low temperature stage is a serious abiotic stress for rice at the booting in areas of high platitude and altitude. Cold tolerance is a complex trait controlled by many quantitative trait loci (QTLs). This stuty focused on the F14、F15 RILs including 225 lines which were derived from a cross Towada, a Japanese variety as female parent and Kunmingxiaobaigu as male parent, to identify QTLs controlling cold tolerance at booting stage. The evaluation of cold tolerance at booting stage was conducted in Songming(altitude 2418m), Lijiang(altitude 1915m) and Mile(altitude 1146m) (during 2012-2013), and got the data about spikelet fertility、specific spikelet fertility and panicle exsertion. A linkage map with a total of 132 SSRdistributing over 12 chromosomes in rice was constructed to detect QTLs releteed to cold tolerance at booting stage. The main results were as follow:1. A linkage map covering 1891.58cM, with 132 SSR was constructed based on an F14 population consisting of 225 lines of a cross between Kunmingxiaobaigu and a Japanese variety, Towada, the average distance of adjacent molecular markers is 14.33cM.In addition, there were 37 segregation distortion markers, distributed on all the chromosomes except chromosome 4 and 5,and most of them tend to Kunmingxiaobaigu.2.8 QTLs were detected on chromosome 2、3、6、8、10 and 11 using The evaluation of spikelet fertility, the value of LOD was from 2.10 to 5.19, which explained the observed phenotypic variance from 4.01%to 12.25%.The QTLs qSF-8-2 and qSF-3 on chromosome 8 and 3 displayed the largest effect reaching a value above 10%.3. The linkage map constructed was used to detect the cold tolerance with the evaluation of specific spikelet fertility. There were 12 QTLs detected on chromosome 1、 2、3、6、7、8 and 11.The values of LOD was from 2.01 to 4.91,the variation of phenotype was from 4.35% to 17.87,the QTL qSSF-8-3 can be detected 3 times,and displayed the largest effect.4. there were 12 QTLs detected on on chromosome 1、2、4、6、7 and 9, which explained the observed phenotypic variance from 3.72%to 22.17%.6 QTLs including qPE-1-1、 qPE-1-2、qPE-6-1, qPE-7-1、qPE-7-2 and qPE-9-2 were found in more than two growing environments,the QTL qPE-7-1 displayed the largest effect.5. qSF-10-1、qSSF-6, qSSF-8-3、qSSF-8-4, qPE-1-1、qPE-1-2、qPE-4、qPE-6-1、 qPE-7-1 and qPE-9-2 could be detected many times (≥2). The variance explained by qSF-3、qSF-8-2、qSSF-2、qSSF-8-3、qPE-1-2、qPE-6-1 and qPE-7-1 were above 10% in different growing environment, qSF-8-2 and qSSF-8-3 were at the same loci between RM5637 and RM1345 on chromosome 8, they could be detected in the direct cold tolerance evaluation system many times, and displayed the largest effect; however, the QTL qPE-7-1 which was detected in the indirect cold tolerance evaluation described as the major stable QTL could not be detected in the direct cold tolerance evaluation system, but it was at the same loci with the major QTL qRCT7 which was reported by Dai luyuan.The QTLs qSSF-6 which was between RM527 and RM1161 on chromosome 6 and qSSF-8-4 were reported here for the first time.