Title: Tagging quantitative trait loci for heading date and plant-height in important breeding parents of rice (Oryza sativa) Authors
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 13, 2013
Publication Date: N/A
Interpretive Summary: Heading date and plant height conditioned by quantitative trait loci (QTLs) are the two important agronomic traits for rice breeding. The US adapted genetic stock Kaybonnet low phytic acid lpa1-1 and germplasm Zhe 733 have been used for improving rice quality and yield in the US and worldwide, respectively. In the present study, five QTLs responsible for plant height, Qhd1-5, and three QTLs responsible for heading date, Qhd1-3 were identified using simple sequence repeat (SSR) markers. Among the identified QTLs for heading date, Qhd1 on chromosome 3 contributed 20% of phenotypic variation and whereas, for plant height, Qht1contributed 42% of phenotypic variation. Other QTLs contributed minor efforts and among them, Qhd5 and Qht2 are new QTLs that have not previously been reported. The identified SSR markers in this study will be useful for selection of heading date and plant height using marker assisted selection.
Technical Abstract: Heading date and plant-height are important agronomic traits and critical for the desired high yield level in rice breeding programs. Both traits are controlled by quantitative trait loci (QTLs). In this study, we identified five QTLs for heading date and three for plant-height using 255 individuals of a F10-11 recombinant inbred line (RIL) mapping population derived from a cross between a genetic stock KBNTlpa1-1 and rice germplasm Zhe733. Simple sequence repeat (SSR) markers were used for genotyping. Interval mapping (IM) and composite interval mapping (CIM) were performed to identify and map QTLs for heading date and plant-height. Qhd-1 on chromosome 3 from Zhe733 had the largest effect on heading date contributing 20% of the total phenotypic variation. A smaller effect on heading date was observed in Qhd-2, Qhd-3, Qhd-4, and Qhd-5 with additive effects of two to three days. QTLs, Qpht-1, Qpht-2, and Qpht-3, for plant-height were detected on chromosomes 1, 3, and 11 respectively. Qpht-1 contributed the largest effect representing 42% of the total phenotypic variation. Comparison of the chromosomal locations of QTLs identified in our study with other reported QTLs indicates that QTLs identified in our study were consistent with those identified in other rice populations. The tightly linked SSR markers that flank these QTLs should be desirable for tagging heading date and plant-height genes and facilitating their incorporation into advanced breeding lines using marker assisted selection.