QTL ANALYSIS FOR YIELD TRAITS OF RICE IN EXCLUSION OF MAJOR EFFECT

This study was conducted to detect quantitative traits loci(QTL) for yield traits in the exclusion of major QTLs.In a previous mapping of QTLs for heading date and yield traits using Zhong 156/Gumei 2 recombinant inbred line(RIL) population of rice,a major QTL was located in the interval RM2-RM214 on chromosome 7.Two lines showing the Gumei 2 genotype in this interval were selected and crossed to derive a new RIL population.A total of 25 QTLs were detected,of which 8 also had significant effect in the previous study and the direction of the additive effect always remained unchanged,6 more were located in two of the common QTL regions but significant effects were detected for 3 more traits in each region,respectively.The remaining 11 QTLs were located in regions where no QTL for yield traits were detected in the previous study.Two QTLs detected in the previous population was not detected in the present study,of which one had been shown to exhibit no effect in the background of Gumei 2 genotype in the RM2-RM214 interval,and the other had a minor contribution of 0.55% to the phenotypic variance in the previous study.Comparison between the two RIL populations showed that efficiency of the QTL detection could be greatly improved by eliminating the effect of major QTL.