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Identification and Evaluation of Drought Resistant Cultivars and Experimental Genotypes of Four Warm Season Grasses

Poudel, Rachana
The objective of this study was to identify drought resistant experimental genotypes or cultivars of four commonly used warm season grasses. Bermudagrass (Cynodon spps.), zoysiagrass (Zoysia Willd.), St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze], and seashore paspalum (Paspalum vaginatum Swartz) were used in this study. In this project, drought resistance of the 13 bermudagrass, 13 zoysiagrass, 12 St. Augustinegrass, and 7 seashore paspalum lines were separately studied by evaluating turf quality, leaf firing, normalized difference vegetation index (NDVI), and percent green cover (digital image analysis). All of these parameters were highly correlated. Although lines among the species were not compared, all grasses of the four species responded within one week of stopping watering. Ratings during the dry down cycle were collected until all grasses reached 30% green cover. Though all the grasses were completely leaf fired by 28 days, drought stress was extended up to 90 days. After 90 days of drought all the grasses were re-watered but no grass species survived. The performance of experimental genotypes �OKC 1302� (bermudagrass) and �UGP 10� (seashore paspalum) were better than rest of the entries of each species. None of the experimental genotypes of zoysiagrass and St. Augustinegrass performed better than the commercial cultivar �Zeon� and �Raleigh� respectively.