Mapping QTLs Influencing Stigma Exertion in Rice

J. LOU1, G. H. YUE1, W. Q. YANG1, H. W. MEI2, L. J. LUO2 and H. J. LU1
1 Southern Zhejiang Key Laboratory of Crop Breeding, Department of Agriculture and Biotechnology, Wenzhou Vocational College of Science and Technology, Wenzhou 325006, Zhejiang, P. R. China
2 Shanghai Agrobiological Gene Center, Shanghai 201106, China


LOU, J., G. H. YUE, W. Q. YANG, H. W. MEI, L. J. LUO and H. J. LU, 2014. Mapping QTLs influencing stigma exertion in rice. Bulg. J. Agric. Sci., 20: 1450-1456


Stigma exertion plays an important role in the efficient improvement of commercial seed production in hybrid rice. To understand the genetic basis of stigma exertion, a quantitative trait loci (QTLs) analysis was conducted using the F2 population derived from two indica cytoplasmic male sterility (CMS) maintainers Huhan1B and K17B. QTLs influencing percentage of single exerted stigma (PSES), percentage of dual exerted stigma (PDES) and total exerted stigma (PES) were detected using a linkage map of 92 SSR markers. A total of 1, 3 and 1 QTLs were detected for PSES, PDES and PES, respectively. There were one to five pairs of epistatic QTLs affected stigma exertion. The contribution rate of additive and epistatic effects were in a low magnitude for most cases (0.83%-13.77%) while one QTL (qPES-6) and one pair of epistatic QTL explained 18.82% and 25.44% of total variance. The interval of RM3575-RM3351 on chromosome 5 contained two QTLs for PSES and PDES
with reverse function, while RM8225-RM225 on chromosome 6 influencing PDES and PES functioned in the same way. If qPSES-5 and qPDES-5 were two tightly linked QTLs, recombination between these loci could improve both PSES and PDES. Otherwise the application of qPDES-5 to improve PDES could be selected by MAS in rice breeding practice.

Key words: rice, stigma exertion, QTL mapping
Abbreviations: QTL - quantitative trait locus; RILs - recombinant inbred lines; DH - double-haploid; PSES - percentage of single exerted stigma (%); PDES - percentage of dual exerted stigma (%); PES - percentage of total exerted stigma (%); CMS - cytoplasmic male sterility; SSR - single sequence repeat; PCR - polymerase chain reaction; LOD - log of odd; H2 - Contribution rate (%); A - additive effect; D - dominant effect; AA - additive-by-additive interaction; DA - dominant-by-additive interaction; MAS - marker-assisted selection

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