Multi‐locational screening identifies new drought tolerant warm‐season turfgrasses

During periods of drought, the irrigation needs of current warm-season turfgrass cultivars and frequent municipal water use restrictions present a major challenge to the turfgrass industry. Turfgrass breeding programs have responded by placing more emphasis on improved drought response. During 2012-2013, 560 genotypes of four warm-season turfgrass species developed by five southern breeding programs were evaluated for drought response in replicated field trials at seven locations. Breeders selected 35 genotypes as drought-tolerant selections (DTS) for further evaluation. The objectives of this study were to verify superior drought response among DTS under short-term drought conditions and to assess the effectiveness of this approach as a viable breeding strategy to improve drought response in warm-season turfgrasses. Forty-seven genotypes including standard commercial cultivars of zoysiagrass (Zoysia spp. Willd.), bermudagrass [Cynodon spp. (L.) Pers.], St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze], and seashore paspalum (Paspalum vaginatum Swartz) were exposed to dry-downs in three consecutive years by withholding irrigation and excluding rainfall. Significant differences in drought performance were seen across genotypes over the multiyear study. Statistical contrasts found that DTS of zoysiagrass, St. Augustinegrass, and seashore paspalum generally performed better than the standard cultivars. Top-performing DTS zoysiagrass and St. Augustinegrass genotypes maintained >50% green cover longer than the average of the standard cultivars. Based on this research, multilocational screening for drought tolerance was effective in selection of new genotypes with superior performance to standard cultivars and continued screening of turfgrass germplasm to identify new drought-tolerant genotypes is warranted.