Correlation And Path Analysis Of Traits Related To Drought Resistance And Mapping Quantitative Trait Loci For Root Traits Under Lowland And Upland Ecosystems In Rice (Oryza Sativa L.)

Using 116 DH(Double Haploid) individuals derived from the cross of upland rice IRAT109(Japonica)with paddy rice Yue Fu(Japonica), correlations of the different index of the drought resistance and the different traits were compared to select credible indexes measuring the drought resistance and to identify traits. The relationship of the drought resistance and traits under different conditions was obtained. Contribution of traits was identified by path analysis. It studies relationship among the different mechanism of drought resistance including root traits and physiologic traits. Using a constructed linkage map of rice,QTLs controlling root number and root thickness were obtained.Correlation analysis indicated that plant height, root length, root thickness, root dry matter and rate of root thickness change, rate of plant height change, rate of tiller change in rice had positively and significantly correlation with the drought resistance under both upland and lowland ecosystems. Water potential in rice had positive and significant correlation with drought resistance. There are no correlation evident between Osmotic potential and the drought resistance. Drought-resistant individuals showed higher 1000-grain weight, seed-setting ratio than susceptive -drought ones. Path analysis indicated that root thickness gave the biggest contribution to drought resistant all of traits; root length is the second.We have identified one QTLs controlling root dry matter. The QTLs explained 18.54% of phenotypic variance. It was located at chromosome 9.