Genetic Analysis And Dynamic Developping And QTL Mapping Using RIL Populations Derived From Japonica Lowland And Upland Rice Cross

The root play a very important role in plant drought resistance, in order to identify the growing principle of rice root in different stages, We use a Recombinant Inbred Line (RIL) population including 120 plants, derived from the cross between Japonica upland rice IRAT109 and paddy rice Yuefu, Phenotypic values of root traits, include root number, basal root thickness, maximum root length, root fresh weigh, root dry weight and root volume were obtained under PVP pipe cultivated conditions in 2003 and 2004.basal root thickness stop grow after tilling stage; root number were keep stabilization in grain filling stage; the stage had the maximum root length was grain filling stage; as to root fresh weigh, root dry weight and root volume, their growing were got to the summit in grain filling stage. All the traits finished their growing in grain filling stage; we can use the root traits of grain filling stage in rice root breeding.Conditional analysis on root traits growth and dynamic QTL mapping showed that different root traits regulated by different model in different stage, we detected 89 additive effect QTL,only 2 of them had a general contribution over 10% and 23 over 5%,the percentage of the total number was 26%; 43 of them was QTL×environment interaction QTL, the percentage of the total number was 43%.we detected 87 additive by additive interaction QTL,21 QTL had a general contribution over 5%, the percentage of the total number was 24%,as to QTL×environment interaction QTL, 33 QTL had a general contribution over 32%, only 12 was found in two or more stages, the results indicated that the gene which controlled the root traits was expressed in different stage. Two QTL, brt9a and brt9b,with a strong additive effect contribution were detected in heading stage, can explained 19% and 10% of the total phenotypic variation respectively and could be detected in different environment, they can be used to map-located cloning and marker-assistanted breeding.The member of QTL detected at the heading stage and grain filling stage for root vitality was 22, include 2 and 3 additive effect QTL and 9 and 8 additive by additive interaction QTL respectively. and the total general contribution of additive by additive interaction QTL was 62.8% in heading stage and the value of the grain filling stage was 45.17%, during the two stage, we had not detected the same QTL, indicated that in deferent stage, there have different gene control the root vitality.