Plant species diversity regulates the productivity(1-3) and stability(2,4) of natural ecosystems, along with their resilience to disturbance(5,6). The influence of species diversity on the productivity of agronomic systems is less clear(7-10). Plant genetic diversity is also suspected to influence ecosystem function(3,11-14), although empirical evidence is scarce. Given the large range of genotypes that can be generated per species through artificial selection, genetic diversity is a potentially important leverage of productivity in cultivated systems. Here we assess the effect of species and genetic diversity on the production and sustainable supply of livestock fodder in sown grasslands, comprising single and multispecies assemblages characterized by different levels of genetic diversity, exposed to drought and non-drought conditions. Multispecies assemblages proved more productive than monocultures when subject to drought, regardless of the number of genotypes per species present. Conversely, the temporal stability of production increased only with the number of genotypes present under both drought and non-drought conditions, and was unaffected by the number of species. We conclude that taxonomic and genetic diversity can play complementary roles when it comes to optimizing livestock fodder production in managed grasslands, and suggest that both levels of diversity should be considered in plant breeding programmes designed to boost the productivity and resilience of managed grasslands in the face of increasing environmental hazards.

Festulolium hybrids are being increasingly used worldwide as forage grasses. This is due to their superior agronomic characteristics, which combine yield performance of ryegrasses (Lolium multiflorum and L. perenne) and tolerance against abiotic stress of fescues (Festuca pratensis, F. arundinacea and F. arundinacea var. glaucescens). Despite the widespread use, only fragmentary information exists on their genomic constitution. We used genomic in situ hybridization (GISH) to analyze genomic constitution of over 600 plants from almost all commercially available cultivars of Festulolium. Our results revealed a surprisingly large range of variation in the proportions of parental genomes and in the extent of intergenomic recombination. Using fluorescence in situ hybridization (FISH) with probes for ribosomal DNA, we assessed the frequency of recombination and elimination of particular chromosomes and chromosome groups in three contrasting Festulolium cultivars. This study provides novel information that will aid in understanding the relationship between a genetic make-up and the phenotype of Festulolium hybrids. Our results indicate that GISH might be a useful tool to aid in Festulolium breeding and provide data for a more detailed description of registered cultivars.

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Ghesquiere, M., Humphreys, M.W., Zwierzykowski, Z. (2010). Festulolium. In: ' Eucarpia Fodder Crops and Amenity Grasses (Handbook on Plant Breeding )', Veronesi, F., Posselt, U., Beart, B. (Eds). , pp. 293-316 RONO: 1310 3001Festulolium refers to natural or synthetic intergeneric hybrids between obligate outbreeding species of the Festuca (fescue) and Lolium (ryegrass) genera, species considered frequently as ideal components of agricultural or turf-grass systems. Intermediate forms between the two genera have long been recognized in nature and considered as hybrids (? Festulolium spp.) by taxonomists (e.g., Hubbard 1992) mostly on the basis of the inflorescence shape and their suspected progenitor species? combinations

The phylogeny of Festuca arundinacea Schreb. (2n = 6x = 42) was determined using GISH. Total genomic DNA of putative ancestral species was labelled with rhodamine and hybridized to chromosome preparations of hybrids involving these species and F. arundinacea. The degree of hybridization to chromosomes known to be homologous to the probe DNA was compared with that found simultaneously on chromosomes of the genome of F. arundinacea. It was concluded that the tetraploid species Festuca arundinacea var. glaucescens contributed two genomes and the diploid species Festuca pratensis one, to create the allohexaploid species F. arundinacea.Peer reviewe

Leaf length is an important trait for forage grasses. Molecular marker development offers the opportunity to identify Quantitative Trait Loci (QTLs) and to begin to dissect the genetic regulation of complex traits. The objective of this study was to look for QTLs for leaf length and related traits (plant height, lamina and sheath lengths, leaf elongation rate and leaf elongation duration) in the progeny of a cross between two genotypes of Lolium perenne L. with contrasting leaf length. Measurements were performed in a plant nursery in autumn and spring, and in a heated greenhouse in winter. A high level of variability and heritability was observed for all traits. Lamina lengths at different dates were moderately but significantly correlated. For all traits, QTLs were found and explained between 0AE08 and 0AE44 of phenotypic variance. Although different leaf length QTLs were found at different dates, linkage groups two, four and seven were particularly important.

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So far only very few simple sequence repeat (SSR) markers developed from grass species have had their primer sequences published. To make more markers available to the scientific community, we isolated and sequenced 256 microsatellite‐containing clones from four genome libraries of a Lolium multiflorum×Festuca glaucescens F1 hybrid following enrichment in (TC)n, (TG)n, or both repeats. In this work, we report the primer sequences of 60 SSRs including preliminary results of polymorphism for mapping.