QTL Analysis for Yield Traits Related to Low Nitrogen Tolerance Using Backcrossing Recombinant Inbred Lines Derived from Dongxiang Wild Rice (Oryza rufipogon Griff.)

【Objective】Dongxiang wild rice (Oryza rufipogon Griff.) has strong low nitrogen tolerance and is an important germplasm for low nitrogen tolerance improvement. Identification of genes responsible for low nitrogen tolerance in Dongxiang wild rice is of great importance to understand molecular mechanisms of low nitrogen tolerance and develop rice varieties with low nitrogen tolerance. 【Method】Quantitative trait loci (QTLs) for plant height and yield traits under low and normal nitrogen conditions was identified using backcrossing recombinant inbred lines (BC1F12) derived from an interspecific cross Xieqingzao B // Dongxiang wild rice/Xieqingzao B and its genetic linkage. 【Result】A total of 57 QTLs were detected in 33 regions on all chromosome, except chromosome 4 and 8. They explained individually 3.17%~63.40% phenotypic variation, and 32 QTLs of them had favorable alleles derived from Dongxiang wild rice. Nineteen QTLs were simultaneously detected under both nitrogen treatments, and 38 QTLs were only identified under single nitrogen treatment, suggesting various genetic mechanisms in rice growth and yield formation under low and normal nitrogen conditions. 【Conclusion】Fourteen QTL clusters, 43 QTLs included, scattered on seven chromosomes, indicating the common genetic-physiological mechanisms behind different traits, and the QTL pyramiding for low nitrogen tolerance can be achieved by molecular marker-assisted selection.