Rice Yield Components And QTL Mapping At Heading Stage

Yield reflects the productive capacity of varieties,while heading date determines the regional and seasonal adaptability of varieties.Heading date and yield trait are quantitative traits controlled by multiple genes and are easily affected by environment.although many QTLs for heading and yield traits have been fine-mapped and cloned in rice,but the genetic regulatory network is still unclear.More QTLs controlling heading date and yield-related traits need to be mapped,cloned and functionally studied.In this study,Qianhui 136 was choose as the female parent and Zhonghui9308 as the male parent to construct a set of recombinant inbred line population which contains 250 lines by single seed descent method,and QTLs for yield components,heading date and plant height were analyzed under Guiyang long-day length and Sanya short-day length conditions.In addition,considering the time and labor consuming of traditional QTL mapping,residual genetic variation in advanced breeding lines was used to rapidly map heading date QTL.The main results are described as follows:1.Genetic map was constructed by IciMapping4.2 software.The total genetic distance is 1118.9 cM with an average spacing of 7.82 cM.2.QTLs for rice yield components,heading date and plant height were analyzed using the Qianhui 136/Zhonghui 9308 recombinant inbred line population.A total of52 QTLs were detected in two different environments,Guiyang and Sanya.Single QTL could explain 2.94 to 50.68% of the phenotypic variation.Except chromosome 9,all of the remaining 11 chromosomes detected significant QTL effect.31 and 32 QTLs were detected in Guiyang and Sanya,respectively.Among which,11 QTLs were detected in both trials.There are 11 and 9 QTLs that explain more than 10% of the phenotypic variation in Guiyang and Sanya,respectively.all of the major QTL regions detected in this study contain cloned QTLs for yield or heading date except for q PN3.Considering that q PN3 can be stably detected in two environments,this QTL will be focused for fine-mapping and cloning in the next step.3.Two QTLs for heading stage,qHd5 and qHd10,were identified by applying of residual genetic variation in advanced breeding lines using QTL-seq technique.Furthermore,the two QTLs were validated by linkage analysis.