The genetic control of induction to flowering has been studied extensively in both model and crop species because of its fundamental biological and economic significance. An ultimate aim of many of these studies has been the application of the understanding of control of flowering that can be gained from the study of model species, to the improvement of crop species. The present study identifies a region of genetic synteny between rice and Lolium perenne, which contains the Hd3 heading-date QTL in rice and a major QTL, accounting for up to 70% of the variance associated with heading date in L. perenne. The identification of synteny between rice and L. perenne in this region demonstrates the direct applicability of the rice genome to the understanding of biological processes in other species. Specifically, this syntenic relationship will greatly facilitate the genetic dissection of aspects of heading-date induction by enabling the magnitude of the genetic component of the heading-date QTL in L. perenne to be combined with the sequencing and annotation information from the rice genome.

Summary• Quantitative trait locus (QTL) mapping, which can be a useful tool for dissecting complex traits, has been used here to study the regulation of fructan metabolism in temperate forage grasses.• An F2 mapping family, derived from a high water-soluble carbohydrate (WSC) × low WSC cross, was used to map fructans and the other components of WSC (sucrose, glucose and fructose) in leaves and tiller bases of perennial ryegrass ( Lolium perenne ) in spring and autumn. To characterize regions of the genome that control basic carbohydrate metabolism, a strategy to minimize the impact of genotype (G) × environment (E), and E-effects on the characterization of G-effects, was adopted.• Most traits were highly variable within the family. There was also considerable year-to-year environmental variation. However, significant genetic effects were detected, and several traits had high broad-sense heritability. QTL were identified on chromosomes 1, 2, 5 and 6. Leaf and tiller base QTL did not coincide. Individual QTL explained between 8 and 59% of the total phenotypic variation in the traits.• Fructan turnover, metabolism and their genetic control, and the effect of environment, are discussed in the context of the results. Abbreviations AFLP, amplified fragment length polymorphism; DP, degree of polymerisation; G × E, genotype by environment; HPLC, high-performance liquid chromatography; LOD, log-odds score; QTL, quantitative trait locus (loci); RFLP, restriction fragment length polymorphism; SSR, simple sequence repeat; STS, sequence-tagged site; WSC, watersoluble carbohydrate.

Contents Summary 9 Background 10 Objectives, breeding methodologies and progress in grass breeding 12 Markers and their suitability for genetic analysis in grasses 13 Associating markers to genes for ‘sustainability’ in the grasses 13 The genetic control of flowering time 16 Target traits: resilience against climate change and resistance to abiotic stresses 17 Target traits: carbohydrates and sustainable ruminant animal production 19 Target traits: grass biomass, climate change and energy sustainability 21 Conclusions 21 References 22 Summary Here, we review the current genetic approaches for grass improvement and their potential for the enhanced breeding of new varieties appropriate for a sustainable agriculture in a changing global climate. These generally out‐breeding, perennial, self‐incompatible species present unique challenges and opportunities for genetic analysis. We emphasise their distinctiveness from model species and from the in‐breeding, annual cereals. We describe the modern genetic approaches appropriate for their analysis, including association mapping. Sustainability traits discussed here include stress resistance (drought, cold and pathogeneses) and favourable agronomic characters (nutrient use efficiency, carbohydrate content, fatty acid content, winter survival, flowering time and biomass yield). Global warming will predictably affect temperature‐sensitive traits such as vernalisation, and these traits are under investigation. Grass biomass utilisation for carbon‐neutral energy generation may contribute to reduced atmospheric carbon emissions. Because the wider potential outcomes of climate change are unpredictable, breeders must be reactive to events and have a range of well‐characterised germplasm available for new applications.

We report on the evaluation of a novel grass hybrid that provides efficient forage production and could help mitigate flooding. Perennial ryegrass (Lolium perenne) is the grass species of choice for most farmers, but lacks resilience against extremes of climate. We hybridised L. perenne onto a closely related and more stress-resistant grass species, meadow fescue Festuca pratensis. We demonstrate that the L. perenne × F. pratensis cultivar can reduce runoff during the events by 51% compared to a leading UK nationally recommended L. perenne cultivar and by 43% compared to F. pratensis over a two year field experiment. We present evidence that the reduced runoff from this Festulolium cultivar was due to intense initial root growth followed by rapid senescence, especially at depth. Hybrid grasses of this type show potential for reducing the likelihood of flooding, whilst providing food production under conditions of changing climate.