Humphreys, M. O., Feuerstein, U., Vandewalle, M., Baert, J. (2010). Ryegrasses, In: Handbook of Plant Breeding: Fodder Crops and Amenity Grasses, Volume 5, Springer New York, pp. 211-260, 2010In the temperate regions of the world ryegrasses comprise the main sown forage grasses of which the outbreeding perennial, Italian and Westerwolths ryegrasses are the most economically important. This chapter presents information on the origin and systematics of these forage grasses which share a high degree of genome ancestry with the cereals originating in the eastern Mediterranean basin. It considers how plant breeding has enhanced natural genetic resources to produce valuable new varieties with improved production and livestock nutrition characteristics together with increased tolerance of environmental stresses caused by biotic (pests and diseases) and abiotic (temperature, water and mineral extremes) pressures. The challenge of maintaining the optimum balance between vegetative growth and seed production is also addressed. Breeding methodologies based on traditional techniques are discussed and the integration of new biotechnologies into breeding programmes is reviewed. Breeding achievements are evaluated and future goals considered in relation to the increasingly diverse demands placed on grassland to provide ecosystem services, amenity value and systematic breeding as well as providing feed for ruminants
Crown rust resistance is an important selection criterion in ryegrass breeding. The disease, caused by the biotrophic fungus Puccinia coronata, causes yield losses and reduced quality. In this study, we used linkage mapping and QTL analysis to unravel the genomic organization of crown rust resistance in a Lolium perenne population. The progeny of a pair cross between a susceptible and a resistant plant were analysed for crown rust resistance. A linkage map, consisting of 227 loci (AFLP, SSR, RFLP and STS) and spanning 744 cM, was generated using the two-way pseudo-testcross approach from 252 individuals. QTL analysis revealed four genomic regions involved in crown rust resistance. Two QTLs were located on LG1 (LpPc4 and LpPc2) and two on LG2 (LpPc3 and LpPc1). They explain 12.5, 24.9, 5.5 and 2.6% of phenotypic variance, respectively. An STS marker, showing homology to R genes, maps in the proximity of LpPc2. Further research is, however, necessary to check the presence of functional R genes in this region. Synteny at the QTL level between homologous groups of chromosomes within the Gramineae was observed.LG1 and LG2 show homology with group A and B chromosomes of oat on which crown rust-resistance genes have been identified, and with the group 1 chromosomes of the Triticeae, on which leaf rustresistance genes have been mapped. These results are of major importance for understanding the molecular background of crown rust resistance in ryegrasses. The identified markers linked to crown rust resistance have the potential for use in marker-assisted breeding. Heredity (2005) 95, 348-357.
In view of the expected increase in drought periods, researchers and breeders are searching for forage grasses that are more tolerant to drought stress. This study wanted to examine the physiological and biochemical reactions of nine forage grass varieties belonging to Festuca, Lolium and Festulolium under mild drought stress conditions in a semi-controlled field experiment. A mild drought stress treatment was applied in the period between cut II and cut III using three large mobile rain-out shelters equipped with sprinkler irrigation systems. The experiment consisted of two soil moisture treatments: (1) control where a soil moisture level of around 20% v/v was maintained and (2) drought stress where the soil moisture level decreased to 7.5% v/v. The experiment was cut 5 times in 2014 and 4 times in 2015. A total of nine varieties from five species of forage grasses were evaluated: L. perenne, L. multiflorum, F. pratensis, F. arundinacea and F. braunii. Dry matter yield, gas exchange parameters and chlorophyll fluorescence were significantly lower in drought stress than under control conditions and the physiological parameters reacted within 2 weeks after the start of the drought treatment in all species. In contrast, drought stress significantly increased water use efficiency, the content of proline, phenolic acids, flavonoids, water soluble carbohydrates and decreased neutral and acid detergent fibre on both years. Based on total dry matter yield and tolerance indices the most drought tolerant species were L. multiflorum in the first and F. arundinacea in the second investigated year.
Background & aims: Roots are of paramount importance in protecting grassland in numerous ecosystem services e.g. soil organic matter build-up. However, studies that quantified root biomass in grasslands predominantly focused on areas managed less intensively than the management that is common to most North-West European grassland-based farms. To fill this knowledge gap, we compared, root and stubble biomass, the distribution in the soil and root diameter classes of five common European forage grass species grown under intensive management. Methods: On a 3 year old trial comparing yield of five cool season forage grass species at two N fertilization levels (190 kg N ha−1 yr−1 or 300 kg N ha−1 yr−1) we sampled root and stubble biomass until a depth of 90 cm deep. Results: Tall fescue (Festuca arundinacea) displayed the highest root and stubble biomass and had the highest mean root diameters of all studied grass species. The total dry biomass below cutting height (stubble + roots up to a depth of 90 cm below the soil surface) varied between 18 and 19 tonnes ha−1 for tall fescue and 10 and 11 tonnes ha−1 for Festulolium at 190 kg N ha−1 yr−1 and 300 kg N ha−1 yr−1, respectively. Conclusions: Our findings emphasize that in intensively managed grassland, root and stubble biomass under a 3 years old sward can be as high as 19 t DM ha−1. Owing to the high forage and root biomass of tall fescue, this species has a high potential in maintaining several ecosystem services
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