With the exception of the undesirable characteristic of summer dormancy and the accompanying low aesthetic value, crested wheatgrass has many desirable characteristics in semiarid environments, making it a promising candidate for lower water use turf. Using a population of 27 half-sib families, this study characterized the underlying genetics of turf quality (based on a 1–9 rating scale) of crested wheatgrass and compared the performance of crested wheatgrass turf with traditional control cultivars (‘Cody’ buffalograss, ‘Gazelle’ tall fescue, ‘Manhattan 3’ perennial ryegrass, and ‘Midnight’ Kentucky bluegrass) over 2 years under space-planted conditions. Heritability estimates were generally high (h2 = 0.44 to 0.84) and suggested a strong additive genetic component for crested wheatgrass turf quality throughout the summer months. Genotypic correlations among the monthly turf quality scores were very high (greater than 0.90) indicating a strong commonality for the genetics underlying turf quality during any point in the growing season. Thus, a breeding program aimed at improving turf quality in this population of crested wheatgrass would stand a good chance for success. However, primarily as a result of summer dormancy, the crested wheatgrass turf performed poorly compared with the control cultivars during late spring and early summer. Turf quality scores in early July were ≈3 for the crested wheatgrass half-sib families compared with scores between 5 and 6 for the traditional turf species. Thus, crested wheatgrass, for the near future, will likely be a viable turf candidate only in situations in which turf aesthetics are secondary to a desire for low-input requiring species.
Joseph G. Robins, Blair L. Waldron and Paul G. Johnson
B. Shaun Bushman, Lijun Wang, Xin Dai, Alpana Joshi, Joseph G. Robins and Paul G. Johnson
Much of semiarid western North America is salt affected, and using turfgrasses in salty areas can be challenging. Kentucky bluegrass (Poa pratensis L.) is relatively susceptible to salt stress, showing reduced growth, osmotic and ionic stress, and eventual death at moderate or high salt concentrations. Considerable variation exists for salt tolerance among kentucky bluegrass germplasm, but gaining consistency among studies and entries has been a challenge. In this study, two novel kentucky bluegrass accessions recently reported as salt tolerant (PI 371768 and PI 440603) and two cultivars commonly used as references (Baron and Midnight) were compared for their turf quality (TQ), stomatal conductance (g S), leaf water potential (ψLEAF), electrolyte leakage (EL), and accumulation of inorganic ions under salt stress. TQ, ψLEAF, and EL were highly correlated with each other while only moderately correlated with g S. The tolerant accessions showed higher ψLEAF and lower EL than the cultivars Midnight and Baron at increasing salt concentrations and over 28 days of treatment. The accumulation of sodium (Na) and calcium (Ca) in the leaves was highly correlated and did not vary significantly among the four entries. Genes involved in ion transport across membranes, and in antioxidant activities, were significantly induced on salt stress in the tolerant accessions relative to the susceptible. These data indicate the ability of tolerant accessions to ameliorate oxidative stress and prevent EL, and confirmed the tolerance of germplasm previously reported on while indicating mechanisms by which they tolerate the salt stress.