Golf course superintendents in the southwestern United States (Tucson, Ariz.; Phoenix, Ariz.; Las Vegas, Nev.; Orange County, Calif.) were surveyed to assess attitudes toward using reuse water for irrigation. Eighty-nine golf course personnel returned the survey, with 28% indicating that they irrigate with municipal water, 36% with well water, and 27% with reuse water. The reason for switching to reuse water varied by state, with 40% of respondents switching in Arizona because of mandates, 47% switching in Nevada because of cost incentives, and 47% switching in California because it was considered a more reliable source of water. Less than 20% of the respondents rated the use of reuse water on golf courses and parks to have a negative impact on cost, the environment and health. However, respondents indicated that using reuse water does have a negative impact on the operations of the golf course, with pond maintenance and irrigation maintenance having the highest negative impact (∼80%). Multiple regression analysis revealed that among those who indicated that using reuse water would have a negative impact on golf course management, a higher percentage were individuals who had a greater number of years of experience irrigating with reuse water (P = 0.01) and individuals who have taken classes on how to use reuse water (P = 0.05). Respondents who currently irrigate with reuse water indicated they had changed a wide range of landscape and turfgrass management practices as a result of using reuse water. Based on the results of this survey, it was concluded that golf course personnel in the southwestern U.S. do not oppose the transition to reuse water for irrigation. However, it was also clear they recognize using such water negatively impacts their golf courses' operations.
D.A. Devitt, R.L. Morris, D. Kopec, and M. Henry
H.L. Ko, R.J. Henry, P.R. Beal, J.A. Moisander, and K.A. Fisher
An assessment was made to determine the suitability of RAPD analysis for identification of the Australian wildflower Ozothamnus diosmifolius (Vent.) DC [syn. Helichrysum diosmifolium (Vent.) Sweet] cultivars and lines. Of 19 arbitrary primer sequences tested, 16 revealed a high degree of polymorphism between the six most important genotypes with commercial significance, producing a total of 166 markers, of which 70% were polymorphic. Several primers (such as OPD-03 and OPM-07) were able to distinguish all tested genotypes from one another, showing an intracultivar consistency. These results indicate that RAPD analysis is a useful tool for establishing genetic diversity in this species as well as assisting in commercial protection of plant breeders' rights.
S.M. Hum-Musser, T.E. Morelock, J.B. Murphy, and R.L. Henry
Seed germination of spinach (Spinacia oleracea L.) is partially inhibited by a high germination temperature (35 °C). Tolerance of high germination temperatures varies widely depending on the variety used. We ascertained that seed germination of these spinach varieties was thermoinhibited at 35 °C and secondary dormancy was not induced as seeds germinated when transferred to optimum germination conditions (20 °C). Treatment with 99% oxygen and 10 ppm kinetin significantly increased germination of thermoinhibited varieties at 35 °C. During heat stress, all organisms produce heat shock proteins (HSPs), which may function as molecular chaperons, are possibly required for the development of thermotolerance, and may be crucial for cell survival during heat stress. Western blotting of SDS-PAGE gels using antibodies to various heat shock proteins indicated that spinach varieties with the highest degree of thermotolerance have higher levels of HSP expression than varieties with the lowest degree of thermotolerance during germination. These results suggest that thermotolerance could be further improved, either through a breeding program or possibly by genetic engineering.
Clinton J. Steketee, Alfredo D. Martinez-Espinoza, Karen R. Harris-Shultz, Gerald M. Henry, and Paul L. Raymer
Seashore paspalum (Paspalum vaginatum Swartz) is a warm-season turfgrass species primarily used on golf courses and athletic fields, and is often impacted by the disease dollar spot caused by Sclerotinia homoeocarpa F.T. Bennett. Dollar spot is the most common and economically important turfgrass disease in North America, and current management of this disease relies heavily on frequent fungicide applications. An alternate management strategy is host plant resistance, but a better understanding of the interactions between pathogen isolates and the host species is needed to effectively incorporate this resistance into elite seashore paspalum genotypes. The goal of this study was to gather host plant/isolate response data that could be used to develop an effective and efficient screening protocol for resistance to this important disease. Five genotypes of seashore paspalum (‘Aloha’, ‘SeaIsle 2000’, ‘SeaIsle 1’, ‘SeaIsle Supreme’, and 05-1743) varying in dollar spot resistance were inoculated with five isolates of S. homoeocarpa in repeated field studies during 2012 and 2013. Isolates used were from three warm-season and one cool-season turfgrass species. Inoculated plots were evaluated visually and using digital image analysis (DIA) for disease development over time and for number and area of infection centers at two rating dates each year. Statistical differences among the seashore paspalum genotypes and inoculation/isolate treatments were detected for area under the disease progress curve (AUDPC) values, number of infection centers, and infection center area. A significant interaction between seashore paspalum genotype and S. homoeocarpa isolate effects was not observed, indicating that host plant resistance genes are likely not isolate specific. Using this information, breeders should be able to use one highly virulent S. homoeocarpa isolate to screen for host plant resistance in seashore paspalum.