QTL Mapping Of Rice Quality Traits Using Koshihakari/Guicha02Ril Porulation And Development Of The Chromosome Segment Substitution Lines

With the development of domestic economy and standard of living, people become pay more attention to rice quality, especially the eating quality and nutritional quality.Rice quality is the determinant of marketing value of rice. Rice with high quality often sells higher price. Hence, improving rice quality not only meets the consumers’demands,but also greatly increases the value of rice and farmers’income. However rice quality is a complex quantitative traits. In order to research precisely, it often need to construct special population to dissect the quantitative location. In this study, we have analyzed the quantitative trait locations,that are involved in the control of grain length,grain width,length-width ratio, percentage of grains with chalkiness,thousand-seed weight,fat content, protein content, amylose content and RVA profile properties. Further, we are preparing to construct the chromosome segment substitution lines derived from Koshihikari/Guichao2.The results are as follows:1. In this study,we characterized QTLs of rice quality including grain length,grain width,length-width ratio, percentage of grains with chalkiness,thousand-seed weight, fat content, protein content, amylose content using Koshihikari/Guichao2RIL population. Fifteen additive QTLs,as well as fifteen epistatic QTLs,were analyzed.The fifteen additive QTLs are distributed on all the chromosomes except the chromosome5,7,9and12and the fifteen epistatic QTLs locate on every chromosome but the3th and the12th.Three QTLs, qPGWC-8, qRFC-6a, qAC-6,were detected both in Nanjing and Xinxiang, conformed to be stable QTLs. And threre are no any reports about the qRFC-6a,they may be two new QTLs of percentage of grains with chalkiness and fat content, respectively. These QTLs can be separated by Marker-assisted selection, then, introgressing to another variety to improve the rice quality. 2. correlations between RVA profile properties and other rice quality and QTLs for RVA profile properties analyses were characterized using Koshihikari/Guichao2RIL population in Nanjing and Xinxiang.The results showed that the correlation between RVA profile properties and fat content,besides, protein content and amylase content were high significant, but there were no apparently significant correlations between RVA profile properties and apparent quality. Eighteen additive QTLs were detected for RVA profile characteristics, including peak viscosity (PKV), trough paste viscosity (HPV), final paste viscosity (CPV), breakdown viscosity (BDV), setback viscosity (SBV) and peak time (PeT). A QTLs for these six properties locate in the same interval, between RM190marker and RM588marker, can be detected in two environments. This position overlapped the Wx gene, this indicate that the amylose content significantly affects the RVA profile properties. Otherwise, seven epistatic QTLs with little effect were detected and the contribution rate of epistatic effect was just9.39%.There were two epistatic QTLs interacted with the environments. These epistatic QTLs and their interactions with the environments formed a complex hereditary system of RVA profile properties.But, it mainly the additive QTLs affect the phenotype, hence, the epistatic QTLs do not impact the use of additive QTLs in breeding.3. we developed a BC2F1population with0.902recovering ratio of gentic background,which were composed of63lines derived from43lines with relatively pure genetic background which were selected from184lines of Koshihakari/Guichao2RIL population.