Mapping QTLs For Rice Blast Resistance And Main Agronomic Traits In Recombinant Lnbred Line Derived From Mowanggu And CO39

Many important traits of rice, such as horizontal resistance to disease, yield and quality, are typical quantitative traits. And most of the traits are regulated by the major QTLs and minor QTLs simultaneously. Mapping and cloning QTL to combine with the main effect genes for rice breeding possesses important significance. In this study, We analyzed rice blast resistence and main agronomic traits of recombinant inbred lines (RIL) of blast resistant rice cultivar Mowanggu (MWG) and susceptible cultivar CO39, and combined with composite interval mapping (CIM) method to identify blast resistance QTLs and main agronomic traits QTLs. The main results are as follows:1. Ten blast resistance QTLs were detected in total. They were qDSG2, qDSG3, qDSG4-1, qDSG4-2, qDSG8-1, qDSG8-2, qDSG8-3, qDSG9, qDSG11and qDSG12located on chromosome2,3,4,8,9,11and12, respectively. The LOD values of these QTLs arranged from2.01to16.66, and they could explain the phenotypes variance from4.73%to34.30%. Among these QTLs, except that qDSG3and qDSG8-2were donated by CO39, the other8resistance QTLs were donated by MWG. The LOD and contribution rates of qDSG11were16.66and34.30%. Therefore, qDSG11is a major QTL located between the SSR markers K10and K134on chromosome11.2. Correlation analysis showed that plant height displayed extremely significant positive correlation with flag leaf length; Flag leaf width was extremely significant positive correlated with grain width; The thousand kernel weight was extremely significant positive correlated with grain length, grain width and grain thickness, and there was extremely significant positive correlation between grain thickness and grain width; Flag leaf width displayed significant correlation with flag leaf length and grain thickness.3. According to the phenotypes of7agronomic traits (plant height, flag leaf length, flag leaf width, grain length, grain width, grain thickness and thousand kernel weight) and genotypes of MWG×CO39RIL,10QTLs (qPH1, qFLWl, qGT1, qGW2, qGL3, qPH4, qFLW4, qFLL4, qTGW10, qGW10) were detected and located on chromosome1,2,3,4and10, respectively. The LOD and contribution rates of these QTLs were2.54-15.10and4.35%-35.94%, respectively. Among these QTLs,2QTLs for plant height were qPHl and qPH4,2QTLs for flag leaf width were qFLWl and qFLW4,1QTL for flag leaf length was qFLL4,1QTL for thousand kernel weight was qTGW10,1QTL for grain thickness was qGT1,2QTLs for grain width were qGW2and qGW10,1QTL for grain length was qGL3. The qPH1, qFLW4and qGL3were major QTLs.