Submitted to: Euphytica
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/8/2005
Publication Date: 12/22/2005
Citation: Xu, X., Bai, G., Carver, B., Shaner, G.E. 2005. A qtl for early heading date in wheat cultivar suwon 92. Euphytica. 146:233-237. Interpretive Summary: Heading date is an important trait that determines wheat adaptation to different environments. A mapping population from cross CI 13227 x Suwon 92 was employed to identify the QTL for early heading in wheat cultivar Suwon 92. This population was evaluated for heading date for three years, and analyzed with molecular markers. Two molecular markers closely linked to a major gene for heading date were identified and responsible for 40.4% and 32.2% of the total phenotypic variances, respectively. This gene for heading date was located on chromosome 2DS and named as QHd.osu-2DS. Since the photoperiod-response gene Ppd-D1 was previously mapped in this region, the gene identified herein is either Ppd-D1 with pleiotropic effect or a new gene. Markers linked to the gene have potential to be used for selection for early wheat heading date.
Technical Abstract: Heading date is an important trait that determines wheat adaptation to environments. A recombinant inbred line (RIL) population derived from CI 13227 x Suwon 92 was employed to tag the quantitative trait locus (QTL) for early heading in Suwon 92. This population was phenotyped for heading date in 1994, 1995, and 1997, and analyzed with AFLP and SSR markers. Two AFLP markers (XGCTG.CGCT118 and XGCTG.CGCT60) closely associated with heading date were identified. Across years, XGCTG.CGCT118 and XGCTG.CGCT60 explained 40.4% and 32.2% of the total phenotypic variances, respectively. Interval analysis revealed a major QTL for heading date, designated as QHd.osu-2DS, between AFLP marker XGCTG.CGCT118 and SSR marker Xgwm261. QHd.osu-2DS was 41.2 cM proximal to SSR marker Xbarc124, which was previously mapped on the most distal end of chromosome 2DS, and explained 40.5% of the phenotypic variance in three years. Since the photoperiod-response gene Ppd-D1 was previously mapped in this region, the QTL identified herein is either equivalent to Ppd-D1 or a new Eps QTL. QHd.osu-2DS was coincident with a QTL for leaf rust infection duration, which was previously identified in the same population. These two QTLs may be either closely linked or under pleiotropic genetic control.