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Disease is a major problem in creeping bentgrass (Agrostis stolonifera L.) on golf course putting greens. Genetic composition and uniformity of host populations can affect disease development. This study was conducted to determine the effects of blending creeping bentgrass cultivars on dollar spot (caused by Sclerotinia homoeocarpa F. T. Bennett) severity. `Penn A-4', `Crenshaw', `L-93', `Mariner', and `Penncross' were planted in monostands or as two-way or three-way blends in a completely random design with three replications on a sand-based putting green in the field at College Station, TX. Disease severity was determined by the number of infection centers and by total blighted area. Crenshaw was most susceptible, L-93 most resistant, and all other cultivars were moderately resistant to dollar spot in monostands. Cultivar susceptibility in monostands to S. homoeocarpa was representative of each cultivars contribution to dollar spot severity in blends. In blends, L-93 suppressed, whereas Crenshaw increased dollar spot. Penncross, Penn A-4, and Mariner did not affect dollar spot severity across all blend combinations. Number of infection centers and infected area pooled across all monostands were similar when compared to all two- and three-way blends indicating that dollar spot activity in blends was a compromise between resistance levels of individual cultivars. Two-way blends of Penn A-4, L-93, Mariner, or Penncross with Crenshaw, however, resulted in 46 to 67% fewer infection centers and 71 to 98% less blighted area, when compared to the Crenshaw monostand. These data indicated that blending a resistant cultivar with a susceptible cultivar reduced dollar spot severity in the blended population., CREEPING BENTGRASS is a widely utilized turfgrass species on golf course putting greens across the USA and around the world. Disease is a major problem in creeping bentgrass and one [...]

Development of drought resistant, water-conserving cultivars continues to be an objective of turfgrass breeding programs. This study was conducted to determine for 15 zoysiagrasses [Zoysia japonica Steud., Z. matrella (L.) Merr., and Z. japonica Steud. x Z. tenuifolia Willd.] under greenhouse conditions (i) water relations characteristics, (ii) survival and recovery from extreme water stress, and (iii) the relationship of water relations characteristics to supplemental irrigation requirement determined in field studies. Leaf water potential at zero turgor ([Ψ.sub.L0]) ranged from -1.76 MPa to -2.52 MPa before, and from -2.18 MPa to -2.59 MPa after water stress. Though [Ψ.sub.L0] of genotypes such as Cavalier, El Toro, and Emerald decreased after stress, [Ψ.sub.L0] of genotypes such as Korean Common and DALZ8515 did not change. Osmotic potential at full turgor ([Ψ.sub.Π100]) of genotypes such as DALZ8501 and DALZ8506 was similar or increased after water stress but decreased for genotypes such as Crowne and Korean Common. The [Ψ.sub.L0] and [Ψ.sub.Π100] after stress were negatively correlated with recovery from stress and positively correlated with irrigation requirement. Zoysia genotypes with low relative water content at zero turgor ([RWC.sub.0]), bulk modulus of tissue elasticity ([Epsilon], and apoplastic water fraction (Β) demonstrated poor recovery from stress and required more supplemental irrigation. Cultivars such as Crowne, El Toro, and Palisades had the greatest recovery from stress, the least irrigation requirement, more negative [Ψ.sub.L0] and [Ψ.sub.Π100] and positive [RWC.sub.0], [Epsilon], and Β. This study demonstrates that improvements in biophysical as well as morphological traits should contribute to development of water-conserving Zoysiagrass germplasm., WATER MANAGEMENT AND CONSERVATION continue to be major emphases of the turfgrass industry and turfgrass breeding programs. Water-use restrictions that limit irrigation of urban and suburban landscapes are commonplace. Therefore, [...]