Two quantitative trait loci for grain yield and plant height on chromosome 3 are tightly linked in coupling phase in rice

摘要

Plant height is a very important trait affecting rice production. The introduction of the Green Revolution gene, sd-1, into rice cultivars to create semi-dwarfism has increased grain production. In the development of modern rice breeding, there is an urgent need for a somewhat higher plant for not only maintenance of strong lodging resistance, but also more biomass. In this study, the plant height quantitative trait locus (QTL) qPH3 with moderate effect and the yield per plant QTL qYD3 were identified on chromosome 3 in a population derived from two semi-dwarf cultivars. The 02428 alleles of both QTLs contributed to increasing phenotypic values. In the near-isogenic background, both QTLs exhibited the characteristics of a single Mendelian gene. qPH3 and qYD3 were tightly linked, no more than 130 kb apart, with additive effects of 5.2 cm and 4.4 g, respectively. They were further fine-mapped to a 19-kb region and a 65-kb region, respectively, where the recombination hotspot occurred. The gene encoding gibberellin 20-oxidase associated with plant height was regarded as the candidate of qPH3. Both linked QTLs are in coupling phase, which is convenient for simultaneously selecting both genes for breeding high-ield varieties maintaining strong lodging resistance. Isolation of qYD3 is very promising due to its location in a recombination hotspot region.