SummaryHUB1, also known as Ubl5, is a member of the subfamily of ubiquitin-like post-translational modifiers. HUB1 exerts its role by conjugating with protein targets. The function of this protein has not been studied in plants. A HUB1 gene, LpHUB1, was identified from serial analysis of gene expression data and cloned from perennial ryegrass. The expression of this gene was reported previously to be elevated in pastures during the summer and by drought stress in climatecontrolled growth chambers. Here, pasture-type and turf-type transgenic perennial ryegrass plants overexpressing LpHUB1 showed improved drought tolerance, as evidenced by improved turf quality, maintenance of turgor and increased growth. Additional analyses revealed that the transgenic plants generally displayed higher relative water content, leaf water potential, and chlorophyll content and increased photosynthetic rate when subjected to drought stress. These results suggest HUB1 may play an important role in the tolerance of perennial ryegrass to abiotic stresses.

Bermudagrass [Cynodon spp. (L.) Rich.] is a high‐quality, durable turfgrass with excellent heat and drought tolerance. However, its lack of freezing tolerance limits its use in the transition zone. The development of cultivars with enhanced freezing tolerance would constitute a significant improvement in the management of bermudagrass in this region and could extend its area of adaptation further north. There has been substantial work on screening of common‐type bermudagrass [Cynodon dactylon (L.) Pers.] germplasm for freezing tolerance, but not for the African (Cynodon transvaalensis Burtt‐Davy) germplasm. The purpose of this research was to conduct multiyear field testing and laboratory‐based freezing test evaluations of winter hardiness and freezing tolerance, respectively, of an African and common bermudagrass germplasm collection. A high level of cold hardiness was observed among the germplasm in this study. In field evaluations, plant introductions (PIs) PI 290905, PI 647879, PI 255447, PI 289923, and PI 615161 were the top performers, having consistently greater spring green‐up and reduced winterkill compared with ‘Patriot’, ‘Tifsport’, ‘Quickstand’, and ‘Tifway’, though not always significantly. A comparison between field‐based ratings and calculated lethal temperatures for 50% death (LT50) from laboratory‐based freezing tests showed significant correlations of −0.26 and −0.24 for spring green‐up and winterkill, respectively, suggesting that these controlled freeze experiments could be used to prescreen materials prior to field testing. Overall, results indicate that some of the PIs evaluated in this study can be used as additional sources of cold hardiness in bermudagrass breeding.

Athletic field paints are applied to turf surfaces with little or no acute injury. However, field managers notice chronic declines in turfgrass health after repeated applications. This study examines athletic field paint impacts on spectral quality and associated turfgrass photosynthesis. Growth chamber experiments evaluated effects of red and white athletic field paint as well as one, two, three, and four repeated weekly applications on total canopy photosynthesis (TCP) of perennial ryegrass {Lolium perenne L.). Paint treatments were applied weekly for 6 wk with TCP recorded 24 h after each application using agasexchangesystem.Spectroradiometry experiments evaluated reflection, absorption, and transmission of light at various wavelengths based on paint color, dilution, and thickness. Over a six week period all treatments reduced TCP based on color (P < 0.0001) and dilution (P < 0.0001). Red no-dilution paint produced a 75% reduction in TCP over 6 wk while white 1:1 diluted paint only produced a 19% reduction. Spectroradiometry data suggests this is likely due to reductions in photosynthetically active radiation (PAR) with red paint absorbing 51% of incident PAR while transmitting and reflecting 6 and 43%, respectively. White paint transmitted 5% of PAR while reflecting 95%. Alterations in light spectral quality resulting from athletic field paint applications can impact PAR, which may result in reduced turfgrass health.

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