Location: Forage and Range ResearchTitle: Comparative drought response in eleven diverse alfalfa accessions
|ANOWER, M - South Dakota State University|
|BOE, ARVID - South Dakota State University|
|AUGER, DONALD - South Dakota State University|
|WU, YAJUN - South Dakota State University|
Submitted to: Journal of Agronomy and Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/28/2015
Publication Date: 12/1/2015
Citation: Anower, M.R., Boe, A., Auger, D., Mott, I.W., Peel, M., Wu, Y. 2015. Comparative drought response in eleven diverse alfalfa accessions. Journal of Agronomy and Crop Science. doi: 10.1111/jac.12156.
Interpretive Summary: Limited water resources and changing climates place an increasing demand for drought tolerant agricultural plants. Alfalfa production in non-irrigated and rangeland settings can be negatively affected by limited water necessitating the development of alfalfa that is able to persist and grow with limited water. A collection of 11 alfalfas that are found in semi-arid growing conditions were evaluated for their ability to grow under simulated drought conditions in a greenhouse. Specifically, water allocation was restricted to 100, 75, 50, or 25% of the normal water use of each alfalfa plant. We found that RS, a naturalized alfalfa collected from the Grand River National Grassland in South Dakota, showed the best resistance to drought. RS had the least reduction in stem elongation, relative growth rate, and shoot dry mass production under drought stress. Additionally, RS maintained its root growth, relative water content in the shoots, and leaf chlorophyll content. RS also exhibited the greatest water use efficiency among 11 genotypes. Based on the evaluations in this study, RS appears to be a valuable genetic resource in which to study physiological mechanisms of drought tolerant, and a source of drought tolerance for use in alfalfa improvement breeding programs.
Technical Abstract: Alfalfa (Medicago sativa L.) production is often negatively affected by drought stress. This is particularly true for alfalfa that is cultivated on rangeland. Thus, the development of drought-tolerant alfalfa cultivars is of great significance. A greenhouse study was conducted to evaluate 11 alfalfa genotypes, including several collections that are adapted to rangeland conditions and a commercial cultivar, for their performance under drought. Water supply was adjusted based on the transpiration rate of individual plant to compensate 100, 75, 50, or 25% of transpirational water loss. We found that RS, a naturalized alfalfa that was collected from the Grand River National Grassland in South Dakota showed the best resistance to drought. It showed the smallest reduction in stem elongation, relative growth rate, and shoot dry mass production under drought. Associated with the drought resistance or less sensitivity to drought, RS was able to maintain root growth, shoot relative water content, and leaf chlorophyll content. In addition, RS exhibited the greatest water use efficiency among 11 genotypes. We believe that RS is a valuable genetic resource that can be used to elucidate physiological and molecular mechanisms that determine drought-resistance in alfalfa and to breed alfalfa with improved water use efficiency.