Submitted to: Annals of Arid Zone
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 15, 1995
Publication Date: N/A
Interpretive Summary: Water deficits limit the growth and production of cool-season grasses on semiarid rangelands. Adaptations that allow cool-season grasses to avoid or withstand the influence of drought must be considered in plant improvement programs. Although many techniques are available to evaluate morphological and physiological characteristics related to drought adaptations, few have been successfully utilized in plant breeding programs. Most of this type of research has involved annual crop species, and very little research has focused on cool-season forage grasses. This review examines selection criteria and techniques for improving response to drought for cool-season perennial grasses.
Technical Abstract: Water limits the establishment, growth, and production of grasses on semiarid rangelands, and plant improvement programs for these areas must be capable of screening breeding lines for response to drought. Although many techniques to evaluate various morphological and physiological characteristics have been proposed, few have been successfully used in plant breeding programs. Consequently, a need exists to identify and develop rapid, reliable screening techniques that can assess integrated plant response to drought in large plant populations. Improved seedling emergence has been achieved in Russian wildrye [Psathyrostachys juncea (Fischer) Nevski] by selecting for emergence from a deep seeding depth and long coleoptiles. Water uptake by roots is critical and screening for enhanced seedling root growth in grasses offers considerable promise. In spite of the important role that stomatal control has in regulating plant water loss, limited success has been achieved in incorporating desirable stomatal characteristics into improved grass cultivars. Although osmotic adjustment appears beneficial in some crop species, more research is needed before grasses should be selected based on osmotic adjustment. Selection for improved water-use efficiency in cool-season grasses based on carbon isotope discrimination is a promising approach. Successful incorporation of these various traits into improved grass cultivars necessitates close cooperation between breeders and physiologists.