Genetic analysis of genotype × iron nutrition interaction on coleoptile elongation rate in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

High iron levels in rice soils represent a major problem for seedling establishment and crop growth, and rapid coleoptile elongation is the mechanism for the rice to cope with the induced stress. Quantitative trait loci (QTLs) analysis for coleoptile elongation rate (CER) in rice (Oryza sativa L.) was performed to study the inheritance of CER and its response to Fe nutrition. A recombinant inbred line (RIL) population of 244 lines derived from the cross zhenshan97B/miyang46 was germinated in 2004 under four Fe concentrations (0, 1.79, 7.16, and 14.32 mM). Seven QTLs with additive effects of stimulating CER were detected under the four Fe concentrations and they were localized on chromosome 1, 4, 5 and 7 with LOD ranging from 2.88 to 15.94 and their contribution to total phenotypic variance ranging from 4.17% to 15.87%, respectively. In addition, 21 QTLs with additive × additive epistasis were detected on all chromosomes but 4 and 9. The detected QTLs with additive effect mainly came from the male parent ZS97B. The detected number of QTLs with additive and epistatic effects for CER varied with Fe concentration. An additive QTL with G × Fe effect was detected between RZ460 and RZ730 markers of chromosome 1 using multi-environmental model of QTL Mapper 1.6 and considering Fe concentration as an environmental factor. The pattern of CER in the different Fe concentrations was well characterized by the genetic model of quantitative traits. It was found that some RILs had higher CER than both parents in each Fe concentration.