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Core Ideas: Golf course superintendents often overseed winter‐damaged areas with creeping bentgrass in the early spring when temperatures are not ideal for rapid germination.Typical spring temperatures in the upper Midwest were used to define treatments in a controlled environment study to determine general germination response from early April to late May. Response was measured across 21 cultivars to find those with superior germinability under suboptimal conditions.The study found that creeping bentgrass does not germinate below 45°F. At temperatures typical to mid‐April, the cultivars Proclamation, Declaration, and Pure Select had the best germinability. Re‐establishing creeping bentgrass greens after winter damage can be a significant challenge in cold climates. Golf course superintendents require creeping bentgrass (Agrostis stolonifera L.) cultivars that are able to germinate under suboptimal temperatures to ensure early spring play. Little is known about cultivar differences for cold temperature germination; therefore, we assessed the germinability of 21 creeping bentgrass cultivars in a controlled environment. Temperature treatments represented a range of spring temperatures in Minnesota from 7 April to 25 May. Germination began occurring at the 19 April treatment. Top‐performing cultivars included Proclamation, Declaration, and Pure Select while Independence and Memorial performed poorly. Overall, we found that temperatures below 45°F do not allow for sufficient creeping bentgrass germination regardless of cultivar. There were few relevant differences for the 25 May treatment. Golf course superintendents should carefully consider cultivar differences when seeding at suboptimal temperatures. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) is a coolseason turfgrass species that can exhibit significant freezing injury in northern climatic regions. The objective of this study was to quantify major physiological and biochemical changes occurring during the cold acclimation period in four perennial ryegrass accessions varying in freezing tolerance (two freezing-tolerant accessions, TOL-1 and TOL-2, and two freezing-susceptible accessions, SUS-1 and SUS-2). Plants were subjected to a cold acclimation period of 2°C for 21 d in a controlled environment chamber. Crown tissues were harvested at 0, 7, 14, and 21 d of acclimation for determination of proline, water soluble carbohydrates (WSC), and lipid composition. Leaf photochemical efficiency (Fv/Fm) was also measured weekly before plant sampling for biochemical components. In general, proline levels increased and Fv/Fm decreased during cold acclimation; however, there were no differences in proline accumulation or FyI Fm among the accessions in response to cold acclimation. Water soluble carbohydrates significantly increased in response to 2°C, with TOL accessions (TOL-1 and TOL-2) accumulating higher WSC than SUS (SUS-1 and SUS-2) by 21 d of acclimation. There were also significant changes in major phospholipids classes at 2°C. Specifically, TOL-2 exhibited a higher ratio of membrane stabilizing lipids and unsaturated fatty acid content compared to SUS-1, SUS-2, and TOL-1 by 21 d of cold acclimation. [ABSTRACT FROM AUTHOR]

The primary limitation of tufted hairgrass [Deschampsia cespitosa (L.) P. Beauv.] as a turfgrass appears to be damage caused by billbug (Sphenophorus spp.) herbivory, in this study several sets of germplasm were used in volatile collection studies. Whole-plant volatile collections were made on: i) untreated plants, ii) plants that had been treated with jasmonic acid (JA), and iii) plants that had experienced mechanical damage. In untreated plants, intraspecific differences were found for the amount of hexenyl acetate that was released; this compound has been shown to be involved in important plant volatile-insect interactions. Application of JA resulted in a dramatic increase in the production of monoterpenes, which are known to attract predators of insect pests. (Z)- β-ocimene comprised nearly 9% of the total volatile profile after JA treatment, but was not detected in untreated plants. Mechanical damage of tufted hairgrass plants led to an increased release of characteristic green leaf volatiles such as 3-hexen-1-ol as well as hexenyl acetate. Mechanical damage changed the components of the volatile profile, but the results were quite different from JA treatment. It would be of interest to determine if the selection of tufted hairgrass germplasm that produces high and sustained levels of monoterpenes, in response to JA, would attract sufficient insect predators to make this an effective breeding strategy for insect resistance. [ABSTRACT FROM AUTHOR]

Recently, turfgrass breeders have developed many improved turf-type tall fescue (Festuca arundinacea Schreb.) cultivars. Due to the large number of cultivars currently available to turfgrass managers and researchers, we have classified turf-type tall fescue cultivars into six groups based primarily on several morphological measurements. This type of classification is important for turfgrass breeders because many breeding decisions are made based on observations in a spaced-plant nursery. The major objective of this study was to classify tall fescue cultivars and selections based on spaced-plant measurements and to then compare those results with turf performance. A spaced-plant nursery consisting of 36 cultivars and selections was established in September 1998 at Adelphia, N.J. Plant height, panicle length, flag leaf width and length, subtending leaf width and length, and subtending internode length were measured 10 days after anthesis in 1999 and 2000. Additionally, a turf trial was established at North Brunswick, N.J., that included the same 36 cultivars and selections. The turf plots were evaluated for several traits including overall turf grass quality, density, and susceptibility to brown patch disease. Based on principal component analysis of morphological measurements, along with turf trial data, all cultivars and selections were assigned to one of six groups: forage, early-standard, standard, early semi-dwarf, semi-dwarf, and dwarf. In turf plots, the semi-dwarf, early-semi dwarf, and dwarf groups were the top-performing types in terms of overall turfgrass quality, and the forage and early-standard cultivars had the lowest overall quality ratings. The dwarf types did not perform well under summer stress, especially in terms of brown patch disease incidence. The results of this study suggest that when developing cultivars for higher maintenance situations, turf-type tall fescue breeders should focus on the development of semi-dwarf... [ABSTRACT FROM AUTHOR]

In recent years, turfgrass breeders have given increased attention to the development of lower maintenance turfgrass cultivars. Fine fescues (Festuca spp.) have been identified as potential candidate species for low-maintenance lawns because of their reduced need for water, mowing, and fertilizer. Unfortunately, these species have some weaknesses that must be improved to facilitate their use; perhaps, the most important of these is tolerance to wear and traffic. For this trait to be improved in new cultivars, there must be sufficient heritable variation available for plant breeders to exploit; however, little is known about the heritability of this complex trait in fine fescue species. Therefore, the objective of this study was to determine the heritability of wear and traffic tolerance in three fine fescue species. Replicated field studies were established in North Brunswick, NJ, and St. Paul, MN, and each included 157 Chewing's fescue (Festuca rubra L. subsp. fallax), 155 hard fescue (Festuca brevipilia), and 149 strong creeping red fescue (F. rubra L. subsp. rubra) genotypes. Wear tolerance was evaluated in North Brunswick and traffic tolerance was evaluated in St. Paul during 2015 and 2016 using different simulators to determine both plant performance and broad-sense heritability estimates for wear and traffic tolerance. Broad-sense heritability estimates for the three species when calculated on a clonal basis was between 0.69 and 0.82 for wear tolerance in the North Brunswick location and between 0.49 and 0.60 for traffic tolerance in the St. Paul location. On a single-plant basis, broad-sense heritability estimates for the three species were between 0.31 and 0.45 for wear tolerance in the North Brunswick location and 0.09 and 0.12 for traffic tolerance in St. Paul. However, this research does indicate that improvement of wear and traffic tolerance in fine fescues is possible through recurrent breeding methods based on selection of replicated clonally propagated genotypes rather than selection of single individual plants of a population. This was the first study to determine the genetic effects of wear and traffic tolerance in any turfgrass species. [ABSTRACT FROM AUTHOR]