QTL Mapping and Epistasis Analysis for Yield Components in a RIL Population of Rice (Oryza sativa L. subsp. indica)

A genetic linkage map consisting 168 DNA markers was constructed based on a recombinant inbred line (RIL) population derived from a cross between a high yield indica variey Zhong156 and a low yield indica variety Gumei2. The markers in the linkage map distributed on all the 12 rice chromosomes and covered 1 447.9 cM of the genome. The parents and 304 RILs were grown in China National Rice Research Institute (CNRRI), Hangzhou, China in 2001. The experiments were carried out in two seasons with a randomized complete block design. The statistic software of QTL Mapper 1.01 was applied to detect QTLs and QTL ×environment (QE) interaction for yield components, including PL (panicle length), PN (panicle number), SN (spikelet number), FG (filled grain number), GF (grain fertility), and KW (kilo-grain weight). A total of 30 QTLs with significant additive effects covering all chromosomes except chromosomes 5 and 9 and two QTLs with significant QE interactions were detected. Thirty-one pairs of QTLs showing significant additive × additive epistatic effects for yield components were also detected. Genetic contributions were generally low for QTLs showing epistatic effects compared with QTLs showing additive effects. No significant interaction between epistatic QTLs and environment was detected.