Developing Alfalfa Varieties for a Water-challenged Future

Large portions of the central and southern Great Plains and the western U.S. are regularly plagued by drought and diminishing water resources for irrigation. Alfalfa cultivars adapted to these regions, and that can remain productive under reduced irrigation allotments, are clearly needed. This paper summarizes some of the work that has been conducted to develop alfalfa cultivars that are less sensitive to drought stress. Such efforts include field evaluation of populations for their ability to remain productive under reduced irrigation allotments. Results of some physiology studies tentatively suggest that such populations may possess more extensive root systems. Molecular research has identified DNA markers that are potentially associated with alfalfa drought tolerance. These DNA markers have recently been used to move putative drought tolerance genes into standard and high forage quality type alfalfa cultivars. Fields studies evaluating the impact of these DNA marker alleles on forage productivity and nutritional quality, in these cultivar backgrounds, are in progress under well-watered and water-deficit conditions.