Fine fescues (Festuca L. spp.) comprise a group of five cool-season grasses used in turfgrass systems under many conditions: strong creeping red fescue (F. rubra L. ssp. rubra Gaudin), slender creeping red fescue [F. rubra L. ssp. littoralis (G. Mey.) Auquier], Chewings fescue [F. rubra L. ssp. commutata Gaudin; syn. F. rubra L. ssp. fallax (Thuill.) Nyman], hard fescue (F. brevipila Tracey), and sheep fescue [F. ovina L.; syn. F. ovina L. ssp. hirtula (Hack. ex Travis) M.J. Wilk.]. Their extensive geographic distribution is a result of adaptation to many different environmental and management conditions especially low-input sites. This review summarizes the history, production, establishment, management, use, and availability of fine fescues; discusses strengths and shortcomings of fine fescue; identifies knowledge gaps; and provides an outlook toward further research on this group of grasses. Improved cultivars have been developed in recent years that expand the geographic distribution and uses of species but additional efforts to increase seed yield and improve abiotic and biotic stress tolerances are still needed. Expanded use of fine fescue could be achieved through increased sod production of fine fescue, though current research-based information is limited. Research on fine fescue allelopathy and the contributions of fungal endophytes, both of which could lead to reduced pesticide requirements is important for improved pest management. Future research on fine fescues should focus on implementation and management of new cultivars that possess enhanced abiotic and biotic stress tolerance that will result in fewer inputs and improve the appeal and adoption of these low-input grasses.
Although fungicide resistance in crop pathogens is a global threat to food production, surprisingly little is known about the evolutionary processes associated with the emergence and spread of fungicide resistance. Early stages in the evolution of fungicide resistance were evaluated using the wheat pathogen Zymoseptoria tritici, taking advantage of an isolate collection spanning 20 years in Oregon, USA, and including two sites with differing intensity of fungicide use. Sequences of the mitochondrial cytb protein conferring single-mutation resistance to QoI fungicides and the nuclear CYP51 gene implicated in multiple-mutation resistance to azole fungicides were analysed. Mutations associated with resistance to both fungicides were absent in the 1992 isolates, but frequent in the 2012 collection, with higher frequencies of resistance alleles found at the field site with more intensive fungicide use. Results suggest that the QoI resistance evolved independently in several lineages, and resulted in significant mitochondrial genome bottlenecks. In contrast, the CYP51 gene showed signatures of diversifying selection and intragenic recombination among three phylogenetic clades. The findings support a recent emergence of resistance to the two fungicide classes in Oregon, facilitated by selection for mutations in the associated resistance genes.
Plant pathogens pose a major challenge to maintaining food security in many parts of the world. Where major plant pathogens are fungal, fungicide resistance can often thwart regional control efforts. Zymoseptoria tritici, causal agent of Septoria tritici blotch, is a major fungal pathogen of wheat that has evolved resistance to chemical control products in four fungicide classes in Europe. Compared with Europe, however, fungicide use has been less and studies of fungicide resistance have been infrequent in North American Z. tritici populations. Here, we confirm first reports of Z. tritici fungicide resistance evolution in western Oregon through analysis of the effects of spray applications of propiconazole and an azoxystrobin + propiconazole mixture during a single growing season. Frequencies of strobilurin-resistant isolates, quantified as proportions of G143A mutants, were significantly higher in azoxystrobin-sprayed plots compared with plots with no azoxystrobin treatment at two different locations and were significantly higher in plots of a moderately resistant cultivar than in plots of a susceptible cultivar. Thus, it appears that western Oregon Z. tritici populations have the potential to evolve levels of strobilurin resistance similar to those observed in Europe. Although the concentration of propiconazole required to reduce pathogen growth by 50% values were numerically greater for isolates collected from plots receiving propiconazole than in control plots, this effect was not significant (P > 0.05).
Irrigation and trinexapac‐ethyl (TE) [4‐(cyclopropyl‐α‐hydroxymethylene)‐3, 5‐dioxo‐cyclohexanecarboxylic acid ethylester] plant growth regulator (PGR) have been reported to enhance seed yield in red clover (Trifolium pratense L.). This study examined the interaction of irrigation and TE on seed productivity in first‐and second‐year stands in western Oregon (OR). Two field trials were established and followed over a 2‐yr period (2012–2013, 2013–2014). Treatments consisted of an untreated control, and 140, 280, 420, 560, and 700 g a.i. ha−1 TE PGR applied at BBCH growth stages 32 and 51, and in split applications at BBCH 32 + 51. A single irrigation (100 mm) applied at BBCH 55 increased seed yield and weight in first‐and second‐year stands by 13 and 5%, respectively. Seeds m−2 increased nearly 10% with irrigation in both first‐and second‐year stands in 2013 but not in 2014. Application of TE at BBCH 32 increased seed yield by 13.8% in second‐year stands, except at the 700 g a.i. ha−1 rate, and had no effect or reduced seed yield in first‐year stands. Seed weight was reduced by TE at all timings and reductions were proportional to the rate of application. Seeds m−2 increased in first‐year stands with TE rates ≥280 g a.i. ha−1 and ≥420 g a.i. ha−1 in 2012 and 2013, respectively, and with all rates in second‐year stands. There was no interaction between irrigation and TE in any year. First‐ and second‐year stands will likely benefit from irrigation; however, TE only increased seed yield in second‐year stands.Core Ideas Irrigation and trinexapac‐ethyl independently increase red clover seed yield but there is no interaction between the two. Red clover seed yield is enhanced by increasing seed weight with irrigation whereas seed weight is reduced with trinexapac‐ethyl. Irrigation increases seed yield in first‐and second‐year stands but trinexapac‐ethyl only increases seed yield in second year stands.
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