Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/28/2010
Publication Date: 1/1/2011
Citation: Carter, A.H., Garland Campbell, K.A., Kidwell, K.K. 2011. Genetic mapping of quantitative trait loci associated with important agronomic traits in the spring wheat (Triticum aestivum L.) cross ‘Louise’ by ‘Penawawa’. Crop Science. 51:84-95. Interpretive Summary: Wheat cultivars must possess several traits in order to be acceptable to farmers and end users. Important agronomic traits that affect plant growth include early spring growth, height, heading date, maturity, grain yield and grain volume weight (also called test weight). The goal of this project was to determine the number and location of genes for seedling growth habit, leaf color, plant height, flowering date, maturity date, grain volume weight, grain protein content, and grain yield in a wheat population developed from two spring wheat cultivars that have been widely grown in the Pacific Northwest, Louise and Penawawa. Flowering date and maturity were mainly influenced by a previously identified gene for lack of response to day-length. Two chromosome locations were important for plant height, one for leaf color, one for seedling growth habit and one for grain volume weight. Genes affecting grain yield were located near known pest resistance genes, indicating that resistance to major pests affected yield for this population in the PNW. This research is important because this information can be used to design more efficient selection methods for improved wheat cultivars that are adapted to the Pacific Northwest.
Technical Abstract: Understanding the genetic factors underlying agronomic traits in common wheat (Triticum aestivum L.) is essential to making gains from selection during the breeding process. A set of 188 recombinant inbred lines from a ‘Louise’ by ‘Penawawa’ mapping population was grown in two crop years at two locations in the Pacific Northwest region of the United States to identify quantitative trait loci (QTL) associated with seedling growth habit, leaf color, plant height, flowering date, maturity date, grain volume weight, grain protein content, and grain yield. Using an established genetic linkage map, composite interval mapping was used to identify QTL associated with agronomic traits. QTL for flowering date and maturity date were associated with the Ppd-D1 gene for photoperiod insensitivity. Variation in the QTL for plant height was dependent on location and year, and localized to regions on chromosome 2D and 3B. A QTL for leaf color (ranging from green to blue-green) was identified on chromosome 2B. Seedling growth habit mapped to chromosome 2D, and a significant QTL for grain volume weight was detected on chromosome 1D. QTL were identified for grain yield; however, some of these QTL were associated with other known QTL for pest resistance, seedling growth habit, adaptability or photoperiod insensitivity. Flowering date, maturity date, and plant height were significantly correlated, which resulted from the pleiotropic effects of the Ppd-D1 gene. The identification of agronomic QTL, and the correlations between and among them, is the first step towards making gains from selection for these important agronomic traits.