Location: Cereal Crops ResearchTitle: Quantitative Trait Loci influencing endosperm proteins and end-use quality traits of Hard Red Spring Wheat breeding lines) Author
Submitted to: Czech Journal of Genetics and Plant Breeding
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/10/2011
Publication Date: 12/1/2011
Citation: Tsilo, T.J., Ohm, J., Hareland, G.A., Chao, S., Anderson, J.A. 2011. Quantitative Trait Loci influencing endosperm proteins and end-use quality traits of Hard Red Spring Wheat breeding lines. Czech Journal of Genetics and Plant Breeding. 47:S190-S195. Interpretive Summary: Development of high yielding wheat (Triticum aestivum L.) varieties with acceptable end-use quality is a major focus in breeding programs worldwide. Variations in molecular size of wheat endosperm proteins are known to influence end-use quality traits. In this paper, we report the relationship of grain yield with molecular size distribution of wheat endosperm proteins analyzed by size-exclusion high performance liquid chromatography (SE-HPLC). Two individual protein fractions that were extractable and unextractable using sodium-dodecyl sulfate (SDS) buffer solution were analyzed for size distribution using the SE-HPLC protocol. Individual protein fractions had different associations with grain yield according to solubility in SDS buffer solution and molecule size. SDS-extractable fractions rich in polymeric proteins with small molecule size had a negative correlation (r = -0.41) with grain yield indicating that some of the high yielding lines had low content of those protein fractions in this research. The SDS-unextractable fractions that were rich in very large polymeric proteins did not show any significant association with grain yield. Quantitative trait loci (QTL) that were associated with important fractions of the endosperm polymeric proteins were identified on nine chromosome regions. Some of the novel QTL identified in this study were related to levels of large polymeric proteins in SDS unextractable fractions that are known to have significant positive effect on flour breadmaking quality. There have been efforts to increase total protein content in wheat breeding for improvement of breadmaking quality. However, decrease in grain yield has been pointed out as a problem in breeding for high protein content. Since the large polymeric proteins in the SDS unextractable fractions were not related to variation in grain yield, the QTL for the protein fractions identified in this research are most likely useful in segregating wheat lines to improve breadmaking quality and maintaining high grain yield through marker-assisted selection.
Technical Abstract: Development of high yielding wheat (Triticum aestivum L.) varieties with acceptable end-use quality is a major focus in breeding programs worldwide. Variations in molecular weight (Mw) distribution of wheat endosperm proteins are known to influence end-use quality traits. In this paper, we report the relationship of the size-exclusion high performance liquid chromatography (SE-HPLC) profile of endosperm proteins with grain yield, and several chromosome regions influencing important fractions of endosperm proteins. Flour samples were previously analyzed for Mw distribution of sodium-dodecyl sulfate (SDS) extractable and unextractable proteins using the SE-HPLC protocol. Correlations were calculated between grain yield and HPLC absorbance data obtained at 0.01-min retention time interval. Although both SDS-extractable and unextractable proteins had positive correlations with grain protein content, only SDS-unextractable very high Mw polymeric proteins (UVHP), had no negative association with grain yield, while SDS-extractable fractions rich in low Mw polymeric proteins had a negative correlation (r = -0.41) with grain yield. Nine chromosome regions were associated with important fractions of the endosperm polymeric proteins. Based on HPLC absorbance area % values, multiple QTL explained about 40 and 70% of the total phenotypic variation in SDS-extractable polymeric proteins and UVHP, respectively. Some of the novel QTL identified in this study have potential to increase levels of UVHP and decrease SDS-extractable polymeric proteins, thereby, maintaining high grain yield and acceptable bread-making quality.