Inheritance and QTL mapping of low temperature germinability in rice (Oryza sativa L.)

Quantitative trait loci (QTL) controlling low temperature germinability (LTG) in rice were identified using 81 recombinant inbreed lines (RILs) derived from a cross between a japonica variety Kinmaze and an indica variety DV85. The accurate condition of LTG evaluation was assumed at 15 degrees C for 10 d after removing the effect of dormancy and the second dormancy. By setting check, the scores of LTG in this study were evaluated. The germination rate at 15 degrees C for 10 d was scored to represent the LTG. The LTG of the RILs ranged from 0 to 99%. By single point analysis, simple interval mapping, and composite interval mapping, 5 putative QTL, qLTG-2, qLTG-6, qLTG-7, qLTG-LTG-11 and qLTG-12 were detected on chromosomes 2, 6, 7, 11 and 12 respectively. At the regions of qLTG-2, qLTG-6 and qLTG-11, DV85 alleles increased the LTG, while Kinmaze alleles increased it at the regions of qLTG-7 and qLTG-12. Among the five QTLs reported here, qLTG-2, qLTG-7 and qLTG-12 were newly detected, while the other two QTL-containing regions were close to those previously reported. Epistatic QTL were also detected in this paper.