QTL mapping and epistatic effect analysis of seedling height based on single segment substitution lines in rice

Objective To find out the stable QTLs controlling rice seedling height, analyze their epistatic effects, and provide QTL and theoretical references for molecular breeding of rice seedling height.

Method The single segment substitution lines (SSSLs) with IR65598-112-2 as donor and ‘Huajingxian 74’ as receptor were used as materials. The difference of seedling height between SSSL and ‘Huajingxian 74’ was measured, and the QTLs of seedling height were mapped. The QTL interval was narrowed by substitution mapping, and the epistatic effects of two seedling height QTLs were also analyzed.

Result Two adjacent QTLs (qSH3-1 and qSH3-2) for seedling height were mapped on the long arm of chromosome 3, which were located in the intervals of 32.59−33.08 and 33.16−34.81 Mb, with the lengths of 0.49 and 1.65 Mb, respectively. The additive effects were −0.86 and −1.09 cm, respectively. The phenotypic contribution rate of additive effects were −4.14% and −5.15%, respectively. However, there was no significant difference of seedling height between SSSL harboring these two QTLs and ‘Huajingxian 74’.

Conclusion Two QTLs for seedling height were identified, and there may be significant epistasis effects between the two QTLs.