Responses of new <i>Cynodon</i> genotypes to prolonged and recurrent drought

Abstract Increasing droughts coupled with decreasing available water resources in the southwestern United States highlight the need for new turfgrass cultivars that require less water. A field study evaluated a set of experimental and commercial bermudagrasses ( Cynodon Rich. species) for responses to prolonged and repeated drought conditions in Riverside, CA (USDA Hardiness Zone 10a). Irrigation was withheld for two successive 60‐day cycles of drought, each followed by 14‐day recovery periods in 2020, 2021, and 2022. Plots were evaluated weekly for turf quality and leaf firing, as well as living green coverage, normalized difference vegetation index, and dark green color index using digital imagery. Using living green coverage as a metric for drought performance, seven experimental genotypes (UCRC180012, UCRC180037, UCRC180040, UCRC180146, UCRC180217, UCRC180229, and UCRC180557) were consistently among the top 10 performers, on average retaining over 50% green coverage by the end of each dry‐down cycle. In comparison, all check bermudagrass [ Cynodon dactylon (L.) Pers.] (Riley's Super Sport [Celebration®]) and hybrid bermudagrass ( C. dactylon × C. transvaalensis Burtt Davy) (Bandera®, Santa Ana, DT‐1 [TifTuf®], Tifway II) cultivars had low to moderate responses, ranging from 36% to 0% green coverage. Riley's Super Sport and DT‐1 ranked the highest among check cultivars across years and cycles. Some genotypes appeared to show stress memory, where the first drought period in a year appeared to prime them for a more successful second period each year. Results demonstrate extensive variation among bermudagrasses ( Cynodon spp.) in response to drought and that evaluation over repeated drought cycles appears to be a useful selection tool for Mediterranean climates.