Genetic Analysis For Quality Traits Under Different Environments In Rice

Quality is one of the most important factors affecting production and consumption in rice,which is the main evaluation index for commercial and nutritional value.In recent years,however,the whole rice quality has been slowly improved,still very poor in our country,so that research of quality is an important and hotspot question for genetic breeding.In this study,we used two set of RILs derived from Japonica-Japonica and Indica-Japonica to explored the relationship between quality traits and environmental stability,meanwhile detecded quality related QTLs and nitrogen response.The main results are as follows:1.Sixty-five QTLs associated with quality traits were detected on the chromosomes 1-7 and 9-12 across different environments.These QTLs clustered together on the chromosomes 3,6,9 and 10,which located on chromosome 3,6 and 9 QTLs clustered nearly by GS3,Wx and DEP1 maybe these gene pleiotropic effects.A novel QTL clustered on chromosome10(PM166-RM258),including eight higher percentage of explained phenotypic variation and additive effect QTLs for grian size and cooking and eating quality.Finally,the major QTL qTGW10 was narrowed on the chromosome 10(RM467-RM6368),about flanked 1.47Mb region.2.A set of RILs populations derived from Toyonishiki/Zhongyouzao8 used to materials,CHI and Di index results showed that RILs population has Japonicaclinous attributes,and RILs heading date were very concentrated and have no effect on rice quality.Thirty-nine QTLs for milling and appearance quality were detected,which were distributed on chromosome 1-11 at different conditions,LOD range from 2.50 to 17.47,accounted for 5.65%-21.28%of the phenotypic variance,with additive effects of-5.33 to 13.37.Nine QTLs can be stable expressed under different environments,including control the milling quality of qBR7,qMR1a,qHR1a,qHR3 and qHR4,affecting the appearance quality of qPGWC8,qDPGWCla,qDPGWC8 and qMLW9,and then others QTLs only were detected in single environment.Further analysis and research the key QTL clusters on chromosome 1 and 8,which were detectead for chalkiness traits under different environments.3.According to the results of the properties of test materials and QTL results,Japonica standard as to the most suitable method for analysis cooking and eating quality(ECQ).Thirty-three QTLs associated with ECQ were detected,19 in 2015 and 14 in 2016,were identified on chromosomes 2,3,6,7,10 and 11,explained 7.46%-45.18%of phenotypic variance,and qCV3?qCA6?qCT6?qCV7?qCT11?qCB11?qCH11 and qCA11 were identified under two different environments.These QTLs clustering distribution on the chromosomes 3,6,7,10 and 11,on chromosome 6 nearly by Wx and on chromosome 11 were detected more than two environments,the latter as a novel major clusterfor ECQ.4.Indica-Japonica attribute has a little effect on AC and RVA,the AC and RVA were no significant different in different subspecies,only Indica and japonica have certain difference;RVA characteristics were significantly affect by AC,RVA and CHI and Di were significantly different.93 QTL control by RVA profiles were detected,only 29 QTLs at different environments stable expression,the main effect QTL cluster qRVA2,qRVA6,qRVA7 and qRVAll were detedted more than two environments;stable expression of the major RVA related QTL genetic overlap for AC,but CHI and Di with RVA and AC genetic overlap was no obvious.Compared with RILs populations,sub-RILs populations found QTL number,chromosome distribution,effect values have singnificant different,qRVA2 and qRVA11 was stable expression QTL cluster for two type RILs,which is a key locus for further mapping research.5.A total of 48 QTLs which control elongation traits,including 29 and 19 at Shenyang and Hainan,which were identified on chromosome 1-11;among these QTLs,qML1?qML2?qMS2?qCL2?qCS2b and qMW3 were detected in different environments.However,QTL number,chromosome distribution and effect value with the previous research,no one QTL was detected on the chromosome 6(nearly by Wx),Elongation traits QTLs clustered together on chromosomes 1,2,3,8 and 11,a novel stable expression QTL clustered on chromosome 2,including qML2,qMS2,qCL2 and qCS2 at different environments.6.Quality traits nitrogen fertilizer response have a significant different,compared with normal nitrogen environment,lower nitrogen environment milled rate and head rate decreased,chalkiness traits was significantly increased,MLW basically unchanged,ECQ have obvious trend of high quality.Fifty-nine related quality QTL were detected under different N levels,and then qHR1a,qHR3,qHR4,qPGWC1,qDPGWC1a,qPGWC8,qDPGWC8,qCA7,qCA11,qCH2,qCH11,qCV2,qCV3,qCV11,qCB3,qCB7,qCB11 and qCTS3 were detedted under different nitrogen levels,the rest of QTLs only canbe detected one environment.Chalkiness related QTL were detected on the chromosome 1 and 8,control processing and cooking and eating quality of the pleiotropic effects of QTL were detected on chromosome 2,3,7 and 11,which the next QTL mapping research hotspot.