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Rice growth and productivity are greatly affected by cold stress, which is likely to become more threatening to high and stable yield of rice. To identify cold tolerance at the booting and flowering stage in rice, a set of recombinant inbred lines (RIL) was developed by crossing a cold-tolerant japonica cultivated variety, Jileng1 (JL1), with a cold-sensitive indica cultivated variety, Milyang23 (MY23). The seed setting rate (SST) of the parents and RIL populations were investigated under different temperature environments, then the SST and cold stress tolerance index (CSTI) under the natural low-temperature were used to evaluation the cold tolerance and quantitative trait locus (QTL) mapping. Nine QTL were detected on chromosome 1, 2, 3, 5, 7, 11 and 12, with log-likelihood (LOD) value ranging from 2.64–4.76, these QTL explain the phenotypic variance explained (PVE) range from 3.34 to 12.02%. Among of theses QTL, three QTL qSST1, qSST5 and qSST12 were detected on different years, and they were considered as stable expression QTL. qSST5 was identified on chromosome 5 marker between CMB0526.3 and ID5014265, which many QTL related to cold resistance have been identified in previous studies, so that this QTL was considered as a major QTL for cold tolerance. In addition, thirteen QTL with environmental interactions were detected, and then the additive QTL were all involved in environmental interactions. These result showed that environmental interactions have an significant effective on cold tolerant in rice. The stable expression major QTL identified will help to fine mapping these cold tolerance QTL and provide the gene resources to cultivation cold tolerant variety in rice. |
