No abstract

A 10‐yr, four‐phase collaborative effort among three universities was conducted to develop new hybrid zoysiagrasses (Zoysia spp. Willd.) with improved turf quality, winter hardiness, and pest resistance in comparison to commercial zoysiagrass cultivars, especially ‘Meyer’ (Z. japonica Steud.). In Phase 1, breeding efforts produced 2,858 new progeny that were evaluated for 2 yr across three sites. In Phase 2, only 60 (2%) of 2,858 progeny were selected for advancement to 10 replicated multiyear field trials (Phase 3). Phase 3 revealed 10 promising progeny (assigned DALZ numbers) that required further intensive field and laboratory testing in Phase 4. Phase 4 revealed differences in establishment rate, and DALZ 1701, 1702, 1707, and 1810 had moderate‐to‐good turf performance across seven sites, whereas DALZ 1808 had similar or slightly lower performance. Meyer consistently performed poorly, and ‘Innovation’, a recently released hybrid cultivar, had poor‐to‐moderate performance in comparison to the experimental genotypes, which illustrates the improvements achieved in zoysiagrass breeding in the last 10 yr. Freeze tolerance (LT50, lethal temperature killing 50% of the plants) ranged from −9.8 °C (Diamond) to −14.1 °C (DALZ 1812) with a mean of −12.5 °C. Evidence of large patch [Rhizoctonia solani Kühn, anastomosis Group (AG) 2‐2 LP] in the top 10 DALZ genotypes was 15 to 40% lower than Meyer on several dates. Results indicate that there are multiple genotypes for potential release in the future with improved turf color, winter hardiness, freeze tolerance, large patch resistance, and finer leaf texture suitable for USDA plant hardiness zones ranging between 5b and 8a.

Evaluation of heavy metals in vegetables and soil of agricultural fie1ds of Kathmandu valley was conducted. Highest accumulations of copper (65.5 mg kg-1;, lead 146.75m g kg-1) and cadmium( 2 mg kg-1) from Shankhamul; nickel (29.25mg kg-1) from Nakhu; cobalt (15.25mg kg-1) and manganese (675 mg kg-1; from Balkhu; chromium (73.75 mg kg-1; from Banasthali, zinc (162 mg kg-1) and iron (75636 mg kg-1; from Khusibun were recorded in soil of agricultural fields. Highest accumulations of Cu, Co and Zn were recorded in spinach and Pb in red radish; Ni, Cr and Fe was recorded in broad leaf mustard and Mn in cress leaf while considering the mean of each vegetables studied. Concentration of non-essential but toxic metal like Pb was higher than the normal plant value (0.1-10mg kg-1) in all the vegetables (except potato) collected from different sampling sites.Key words: Heavy metals; Soil; Vegetablesdoi: 10.3126/eco.v12i0.3189 Ecoprint: An International Journal of Ecology 12: 1-9, 2005

Objective methods of estimating green coverage using digital image analysis have been used increasingly by turfgrass scientists. The objective of our research was to evaluate the effectiveness of Canopeo, a relatively new smartphone application, for estimating green coverage of bermudagrass (Cynodon dactylon) emerging from winter dormancy, with or without colorants. A field study was conducted on a research ‘U3’ bermudagrass fairway in Stillwater, OK, during Spring 2019 and 2020. The experiment was conducted as a randomized complete block design with three colorant treatments: Endurant Fairway (FW), Endurant Perennial Ryegrass (PR), and an untreated control. Green coverage of the turfgrass canopy was determined weekly from mid-March to early May using a digital camera and ImageJ software, and a smartphone and the Canopeo application. Green coverage estimates from Canopeo correlated strongly (r = 0.91) with those from ImageJ when no colorants were applied. Correlation between Canopeo and ImageJ was diminished under plots treated with colorants. Canopeo is an effective tool for estimating green coverage of living turfgrasses, but additional calibration may be required for acceptable performance when evaluating greenness of colorant-treated turfgrasses.

Shade and drought commonly occur together in turfgrass systems due to competition with trees for light and soil water. Two greenhouse studies were conducted to evaluate the effects of combined drought and shade stress on bermudagrass [Cynodon dactylon (L.) Pers.] and hybrid bermudagrass [C. dactylon (L.) Pers. × C. transvaalensis Burtt Davy] physiology. 'Latitude 36 Turf Bermudagrass' (Latitude 36 TM ) hybrid bermudagrass and 'Riley's Super Sport' (Celebration ® ) bermudagrass were selected for Experiment 1, while 'Patriot' hybrid bermudagrass was added as a shade-sensitive cultivar in Experiment 2. Washed plugs of each cultivar were planted in growth tubes (10 cm diameter by 46 cm length polyvinyl chloride pipe with a flat bottom cap) filled with a 1:1 topsoil/sand root-zone. Each experiment was conducted as a completely random design with two factors (cultivar and irrigation) repeated under two light environments. Light environment was defined as either adequate light (20.8-26.8 mol m -2 d -1 ) or low light (9.7-10.1 mol m -2 d -1 ) conditions. Irrigation was applied by hand to achieve either 100% (well-watered) or 50% (drought) replacement of evapotranspiration (ET). Under drought conditions, low light resulted in a gradual decline in ET rate, whereas adequate light showed a sharp decline in ET rate over time. Under adequate light, Patriot consumed the most water among cultivars for either well-watered or drought conditions. In contrast, Patriot (well-watered) had the lowest water use in the low light environment, suggesting shade tolerance could potentially influence drought response under low light environments.