Detection Of QTL For Grain Shape And Dissection Of QTGW4 In Rice

Rice is one of the most important food crop in China,and occupied the leading status of grain industry.As the population and grain demand increases,and more land taken up by housing and the development of the public services,the arable land is in the face of the tremendous pressure to produce more food.As a result,breeders pay more attention to the improvement of rice yield.At present,breeders regard the utilization of heterosis as the useful method to increase the rice yield.1.Grain appearance quality traits such as grain length(GL),grain width(GW),length to width ratio(LWR)and 1000-grain weight(TGW),are the most important components of rice yield and grain quality.To detect quantitative trait loci(QTLs)affecting these traits,a set of 76 Chromosome Segment Substitution Lines(CSSLs)population derived from a cross between Xeiqingzao B(XQZB)and Zhonghui 9308(9308)were used.A total of 87 SSR and 33 InDel markers,which were distributed along the rice genome were used to determine the genotypes of the CSSL lines.A total of 108 QTLs governing four traits were identified on 12 chromosomes except chromosome 8 across two environments during 2014 to 2015,including 22 QTLs about grain length,26 QTL about grain width,30 s QTL about length/width ratio,and 30 QTLs grain weight.A total of 21 major QTLs were detected in this investigation.q TGW2-3,qGW5-4,qLWR5-4 and QTLs cluster at interval RM5475-RM1132 for TGW(qTGW2-3),GW(qGW5-4)and LWR(qLWR5-4)were detected and not previously reported.Among these,the contribution rate of qTGW4 is about 20% and it is a new QTL about TGW with significantly genetic effect.These results are valuable for future cloning of the QTLs and the improvement of grain yield in rice.2.1000-grain-weight(TGW)is one of the quantitative traits that is controlled by polygenes,and it can influence the rice yield directly.In the study,a set of 76 Chromosome Segment Substitution Lines(CSSLs)population derived from a back cross between Xeiqingzao B and Zhonghui 9308 was established,and we chose the number 31 line with the significant difference on TGW,and backcross with zhonghui9308,then developed population by choosing the recombinant plants,and detection the phenotype across two environments during 2016-17,and then mapped the qTGW4 at interval RM6535-RM16604 by combining the phenotype and genotype.There are a lot of work that we have to do for future map-based cloning.Therefore,the exploitation and utilization of genes that control the TGW is of vital importance.The major QTLs about TGW will affect the rice production directly,and the development of the minor genes about TGW are beneficial to the research about the intergenic additive effect and epistatic effect,and therefore precise expound the development and genetic mechanism about grain weight genes,and lay a theoretical foundation of genetic breeding.