Identification of quantitative trait loci associated with pre-harvest sprouting resistance in rice (Oryza sativa L.)

One of the most important agronomic problems in rice production (Oryza sativa L.) in high humidity climates is pre-harvest sprouting (PHS). This study was conducted to identify quantitative trait loci (QTLs) for PHS resistance using a recombinant inbred (RI) population derived from a cross between a japonica variety Asominori (relatively susceptible to PHS) and an indica variety IR24 (highly resistant to PHS). Knowledge of the genomic positions of QTLs for PHS resistance in rice could greatly simplify selection of the trait. A total of six QTLs for PHS resistance in rice were detected with 289 restriction fragment length polymorphism (RFLP) markers by both one marker analysis (P < 0.005) and composite interval mapping (CIM) (LOD > 2.0). The two QTLs, located on chromosome 1, accounted for 10.7-20.0% of total phenotypic variations, and the other four QTLs, located on chromosome 4, 5, 7 and 8, respectively, explained 12.3-25.3% of total phenotypic variation. As a result, four alleles from IR24 on chromosomes 1 (two QTLs), 5, 7 and two alleles from Asominori on chromosomes 4, 8 contributed to PHS resistance in rice, respectively. The RFLP markers tightly linked to PHS resistance in rice may be useful for breeding varieties with greater resistance to PHS and adaptable to high humidity climates during the maturation period through the use of marker-assisted selection. (C) 2002 Elsevier Science B.V. All rights reserved.