[QTL analysis for lodging resistance in rice using a DH population under lowland and upland ecosystems]

A DH (doubled haploid) population derived from a cross between Japonica upland rice IRAT109 and Japonica paddy rice Yuefu,was used in this study. Three culm traits, basal culm thickness(BCT), culm length (CL) and culm strength (CS), of DH lines and their parents under upland and lowland ecosystems at milk stage were studied. There were very significant positive correlations between BCT and CL, between BCT and CS and between CL and CS. Data from upland and lowland ecosystems were analyzed respectively and jointly, based on a constructed molecular linkage map(including 94 RFLP markers and 71 SSR markers and covering 1 535. 1cM)and the software QTLmapper version 1.0. A total of nine additive QTLs and five pairs of epistatic QTLs associated with BCT, CL, and CS were found by data analysis respectively. Six additive QTLs and six pairs of epistatic QTLs associated with BCT and CL were detected by data analysis jointly. Six additive QTLs and one pair of epistatic QTLs were detected by both methods. Two additive QTLs and two pairs of epistatic QTLs ( bct1a, c/9, c/6a-c/6c and cs5-cs12) for culm traits with general contributions of over 30% to phenotypic variation might be useful for upland rice lodging resistance molecular breeding under upland ecosystem.