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Validation of QTLs associated with spikelets per panicle and grain weight in rice

Yeo, Sang-Min, Yun, Yeo-Tae, Kim, Dong-Min, Chung, Chong-Tae, Ahn, Sang-Nag
Plant genetic resources 2014 v.12 no.S1 pp. S151
Oryza rufipogon, Oryza sativa, additive gene effects, alleles, breeding programs, chromosomes, grain yield, introgression, marker-assisted selection, microsatellite repeats, molecular cloning, panicles, phenotypic variation, plant breeding, quantitative trait loci, rice, spikelets
In this study, a near-isogenic line (BC₄F₁₀) CR572 developed by introgressing a chromosomal segment from Oryza rufipogon (accession no. 105491) into the Oryza sativa subsp. japonica cv. Hwaseong was found to exhibit a significant increase in the number of spikelets per panicle (SPP) and grain weight compared with the recurrent parent Hwaseong. Quantitative trait locus (QTL) analysis in F₂ generation derived from the cross between CR572 and Hwaseong revealed that two QTLs, qSPP1 and qTGW1, were linked to a simple sequence repeat marker, RM283, on chromosome 1. The additive effect of the O. rufipogon allele at qSPP1 was 13 SPP, and 21.6% of the phenotypic variance was explained by the segregation of RM283. The qTGW1 QTL explained 19.1% of the phenotypic variance for grain weight. Substitution mapping was carried out with five F₃ lines derived from F₂ plants having informative recombination breakpoints within the target region. Substitution mapping indicated the linkage of qSPP1 and qTGW1. The grain yield of CR572 was 18.2 and 15.8% higher than that of Hwaseong at two locations, respectively, mainly due to the increase in 1000-grain weight and SPP. These results are very useful for QTL cluster transfer by molecular marker-assisted selection in rice breeding programmes and for QTL gene cloning by map-based cloning.