Multilocational screening identifies new drought‐tolerant, warm‐season turfgrasses

Abstract

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 Abbreviations: DGCI, dark green color index; DTS, drought-tolerant selection; NDVI, normalized difference vegetative index; %DGCI, percent of initial DGCI; %GC, percent of initial green cover; GC 50 , number of days of dry-down required to reduce green cover to 50% of the initial value; %NDVI, percent of initial NDVI; %TQ, percent of initial visual turf quality.

Water use and management practices on U.S. golf courses

“…Pruning tree roots generally occurs at the boundary where the rough and fairway adjoin in locations where tree roots may compete with turfgrass for water resources, resulting in reduced turfgrass quality. Research efforts into breeding turfgrass have resulted in a wide selection of drought‐tolerant cool‐ and warm‐season turfgrasses (Braun et al., 2022; Katuwal et al., 2022). The wider selection and availability of drought‐tolerant turfgrasses is likely to be a primary reason why more facilities are adopting their use.…”

Warm‐season turfgrass species genotype‐by‐environment interaction for turfgrass quality under drought

“…Conversely, %GC was positively correlated (0.30) with TQD in St. Augustinegrass (Graham et al., 2022). Additionally, high genetic correlations between drought resistance and traits evaluated before the drought stress (TQ (0.62), Digital Green Colour Index (0.65), %GC (0.77) and Normalized Difference Vegetation Index (0.76)) were observed in the same four species under a rainout shelter (Katuwal et al., 2022). Currently, there are few studies in turfgrass that have evaluated the correlation between %GC, TQ under drought and non‐drought.…”

“…In our study, evaluations were conducted under natural occurrence of drought, whereas that study was performed under a rainout shelter. Furthermore, in our study, the traits were evaluated using visual rantings, while the Katuwal et al (2022) study used digital image analysis, which may have contributed to obtaining more accurate phenotypes. Therefore, integrating the use of high-throughput phenotyping technologies in breeding programs will be helpful for improving phenotyping accuracy and consequently increase the selection efficiency for drought resistance in turfgrass breeding (Rockstad et al, 2022;Wang et al, 2022;Zhang et al, 2019).…”

“…Then, the best-performing lines are advanced to replicated trials, where they are evaluated for other traits of agronomic and commercial importance such as turfgrass quality (TQ), establishment rate, fall colour, spring green up, inflorescence abundance, drought, shade and salinity resistances as well as sod production traits Katuwal et al, 2022;Pirtle et al, 2022). Some parameters help plant breeders decide the best strategies to improve selection efficiency in their breeding programs.…”

“…As part of this collaboration, breeding lines from the above‐mentioned universities' breeding programs are initially screened for drought response in multi‐location nurseries (Gouveia et al., 2020; Gouveia, Rios, et al., 2021; Wang et al., 2022). Then, the best‐performing lines are advanced to replicated trials, where they are evaluated for other traits of agronomic and commercial importance such as turfgrass quality (TQ), establishment rate, fall colour, spring green up, inflorescence abundance, drought, shade and salinity resistances as well as sod production traits (Gouveia, Raymer, et al., 2021; Katuwal et al., 2022; Pirtle et al., 2022).…”