Analysis of QTL associated with the allelopathic effect of rice using water-soluble extracts

Quantitative trait loci (QTL) associated with the allelopathic effect of rice (Oryza sativa L.) were identified using RFLP markers. The allelopathic effect was assessed by the growth inhibition of water-soluble extracts from the rice seedlings on lettuce seedlings. QTL analysis was carried out using the F-2 population from the cross between an Indica type line PI312777 (highly inhibitory) and a Japonica cultivar Rexmont (less inhibitory). Seven QTL were identified on chromosomes 1, 3, 5, 6, 7, 11 and 12, One of the QTL on chromosome 6 had the largest effect on the expression of the allelopathic effect of rice and explained 16.1% of the phenotypic variation, The other six QTL explained the variation in the range from 9.4% to 15.1%. A multiple QTL model estimated that five QTL with LOD scores higher than 3.0 explained 36.6% of the total phenotypic variation. Digenic interactions in five pairs between the seven QTLs were detected.