Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/10/2013
Publication Date: 11/12/2013
Citation: Xue, Q, Rudd, J.C., Liu, S., Jessup, K.E., Devkota, R.N., Mahan, J.R. 2013. Yield determination and water use efficiency of wheat under water-limited conditions in the U.S. Southern High Plains. Crop Science. 54(1) 34-47. Interpretive Summary: As global water resources for crop production decline it is important to identify new varieties and management systems to overcome the negative effects of water shortages. Wheat is grown on across the Ogallala region of the U.S. under a wide range of irrigation amounts. In this study the effect of a water deficit on the growth and development of a number of wheat varieties was determined. It was found that the more recently-developed varieties performed better under water stress as compared to the earlier varieties. Comparisons among water efficient and inefficient varieties suggest that improvements have been associated with the varieties that produce the most growth as opposed to varieties that reduce growth to invest more resources into more grain. These findings may prove to be helpful in identifying varieties with higher yields under water shortages.
Technical Abstract: Drought is the most important stress for reducing wheat (Triticum aestivum L.) yield and water use efficiency (WUE) in the U.S. Southern High Plains (SHP). Adoption of cultivars with higher yield and WUE under drought conditions in critical in the area. The objective of this study was to investigate the physiological basis of yield determination and WUE in of wheat in the SHP. A two-year field experiment was conducted in 10 ten genotypes under dryland and irrigated conditions. The newer cultivars or more drought tolerant genotypes had higher yield, biomass, WUE and water use efficiency for biomass (WUEbm)under drought. Genotypes with higher yield had more seeds spike'¹ and higher 1000-kernel weight (TKW). The WUE or WUEbm was determined by yield or biomass as genotypic differences in evapotranspiration were not significant. Biomass at anthesis significantly contributed to higher yield under drought. Yield, spikes m'²,TKW, and harvest index (HI) were correlated to spike, stem and total dry weights per unit area at anthesis. Single stem dry weight was linearly related to seeds spike'¹. For dryland wheat, remobilization of stem carbon reserves contributed to yield in one year, and to seeds spike'¹ and seeds m'² in both years. The amount of remobilization was linearly related to single stem dry weight at anthesis. The results of this study indicated that stem dry weight at anthesis may be an important trait for high yield in SHP environment.