Within-crop genetic diversity increases temporal yield stability in organic winter wheat

Organic farming aims at developing farming systems that do not need unsustainable inputs such as mineral fertilisers and pesticides to regulate the cropping environment. Such systems need crop varieties that are resilient against multiple and variable biotic and abiotic stresses and that make efficient use of the nutrients and resources that are available. Highly genetically diverse cereal Composite Cross Populations (CCPs) have been proposed as an approach to dealing with these stresses (Döring et al., 2011). Field trials investigated the yield stability of two winter wheat CCPs compared to two respective mixtures of their parental varieties as well as high yielding (c.v. Alchemy) and high quality (c.v. Solstice) elite pure-line control varieties at an organic and a non-organic site in the east of England over four trial seasons. The more diverse CCPs demonstrated more favourable static and dynamic yield stability (Annicchiarico, 2002) over the four trial seasons than the respective variety mixtures and the two pure-line varieties at both the organic and non-organic sites. However, an advantage of this stability was found only at the organic site where both the CCPs were higher yielding than the mixtures in the year with the lowest average yields. These results indicate that although the yield potential of CCPs is limited in optimal environments, they are more advantageous at maintaining yield in more adverse environments, such as on organic farms. This supports evidence that diverse crops are able to make efficient use of resources through mechanisms of resilience including compensation, complementation and facilitation (Creissen et al., 2013). These approaches will become increasingly important with increasing challenges from climate change and reduced fossil fuel availability. We acknowledge funding from the European Community’s 7th Framework Programme (FP7/ 2007-2013) under grant agreement no. 245058 SOLIBAM

The biology, behaviour and control of the field slug, Deroceras reticulatum (Müller)

Deroceras reticulatum (Müller) is the most destructive slug pest of arable crops in Britain. Control on a field scale relies heavily on molluscicide pellets. These are often only partially effective; considerable economic loss and collateral damage still occur. More effective targeting of pellets will depend on accurate predictions of damage severity through a better understanding of population dynamics, reliable estimates of surface activity and behavioural studies to evaluate current control strategies. Lifecycle parameters of D. reticulatum were studied. There was considerable variation in growth even under identical conditions and growth rate was inversely related to survival. For field collected slugs, the association between growth rate and temperature was low but negative for spring hatching individuals; however, this was relatively trivial compared to the high and positive association exhibited by those hatching in autumn. For self-fertilised slugs, egg development took longer and the hatching rate was lower than for slugs laid by field collected adults, but the growth rate was faster. It is suggested that field populations may be composed of fast and slow growers, and that this might be determined by whether eggs are fertilised with auto- or allosperm. An equation was derived to predict female-phase maturity from body weight. Refuge traps sampled approximately one third of the surface active population over a 24 hour period. The timing and number of trap entries and exits did not differ between small and large D. reticulatum. Behavioural studies of D. reticulatum demonstrated that the time elapsed and distance travelled before feeding on bait pellets was shorter when they were broadcast compared to drilled. Soil splash did not reduce pellet efficacy. Trails were more sinuous on fine than coarse seedbeds and were reduced by pellets. The practical implications of these results for assessing and controlling D. reticulatum in arable crops are discussed.EThOS - Electronic Theses Online ServiceSustainable Arable LINK project : Department for the Environment, Food and Rural Affairs (DEFRA) : Home Grown Cereals Authority (HGCA) : Bayer, Lonza and De SangosseGBUnited Kingdo

Selecting winter wheat lines from a composite cross population

The extremely diverse genetic variation in wheat Composite Cross Populations (CCP) represents a valuable source of breeding material. Such material could be selected as part of a participatory breeding programme with the potential advantage of selecting adaptation targeted for particular environments. For example, selections could be made aimed at producing lines that would thrive under the wide range of management practices conducted as part of organic and low input farming systems. Ears were selected from a CCP mixed stand under organic field conditions in the UK and Hungary. Selected lines were multiplied as single ear rows and 1m2 plots. The best performing five lines from the two selection sites were trialled in Suffolk, UK, in replicated plots including a commercial control variety (Alchemy) and the original population. Alchemy was chosen due to its good disease resistance and consistent performance at the trial site. Assessments included crop and weed cover, foliar and ear diseases, Leaf Area Index (LAI), crop height, as well as grain and straw yield. The first year of trials has been completed with five of the Hungarian selected lines and trials including locally selected lines are on-going. For the first trial year including only the Hungarian selected lines, there were significant differences among varieties (P<0.001) and Alchemy had the highest average yield. Across all trial entries grain yield was correlated negatively with yellow rust infection on the flag leaf at heading (P<0.001) and with reduced green leaf area during grain ripening (P<0.001). In current trials including locally selected lines, some of the selected lines had significantly lower yellow rust infection than the average of the original CCP and of the control variety Alchemy (P<0.001). There was also greater early ground cover (P<0.005) and (LAI) at tillering (P<0.05) in some lines compared to Alchemy and the original population. Crop cover was also correlated negatively with early weed cover (P<0.05). These observations suggest that it is possible to select lines with enhanced resistance to local disease and the ability to compete with weeds at an early stage. However, because average grain yields and percentage protein content are negatively correlated in this study (P<0.01), this trade-off should not be ignored when selecting lines for specific end uses. This can be avoided by developing mixtures of high performing lines with potentially greater stability than pure-line monocultures. Such mixtures may perform better than the original CCP but with the risk of reduced stability over multiple seasons because of their reduced diversity. Acknowledgements: The work reported here is supported by the EU Core Organic II project COBRA

Applications of crop competitive ability in winter oats (Avena sativa L.)

Crop competition is a key component of an integrated approach to weed management. Variation in competitive ability and competitive traits have been identified in many other crop species, however little work has been done on oats. Trials were carried out over four years at one organic site with five husked and three naked oat varieties. Mid-season Leaf Area Index (LAI) and tillering ability were identified as weed suppressive traits using path analysis. Differences in weed tolerance were found among varieties. Trade-offs may exist between competitive traits and yield potential which could be optimised by limiting competitive traits later in the season. Selection of competitive traits with high heritability, whilst minimising yield penalties, could be applied in breeding programmes to develop varieties with greater weed competitive ability

Applications of crop competitive ability in winter oats (Avena sativa L.)

Crop competition is a key component of an integrated approach to weed management. Variation in competitive ability and competitive traits have been identified in many other crop species, however little work has been done on oats. Trials were carried out over four years at one organic site with five husked and three naked oat varieties. Mid-season Leaf Area Index (LAI) and tillering ability were identified as weed suppressive traits using path analysis. Differences in weed tolerance were found among varieties. Trade-offs may exist between competitive traits and yield potential which could be optimised by limiting competitive traits later in the season. Selection of competitive traits with high heritability, whilst minimising yield penalties, could be applied in breeding programmes to develop varieties with greater weed competitive ability

Changes in Knowledge Management Strategies Can Support Emerging Innovative Actors in Organic Agriculture: The Case of Participatory Plant Breeding in Europe

The “transfer of technology”, typical of a top-down linear process of innovation cannot be used in the new contexts of sustainability, characterised by uncertainty and complexity. There is a need to redefine categories and concepts around which innovation and agricultural policies are built, as those currently in use provide only a partial representation of reality. Innovation paradigms underpinning technological development and public policies design will have a direct impact on decisions regarding which agricultural models will ultimately be supported. Looking at local learning capacity and systems of relations can help to understand the potential to develop innovation within a specific context. This work contributes to the definition of new actors who are developing innovation for sustainability in rural areas. The study focuses on the knowledge systems of farmers who are applying alternative breeding strategies: it uses a network approach to explore the knowledge system in which individual farmers are embedded in order to understand their specific relational features. Three main conclusions emerge from the study: for enhancing the agro-ecological innovation paradigm there is a need to define the ‘innovation broker’, to revise the evaluation system of public research and to integrate innovation and agricultural policies

Multi-Environment Evaluation and Genetic Characterisation of Common Bean Breeding Lines for Organic Farming Systems

It is recognised that one of the main causes for the relative low yields under organic conditions is the use of modern cultivars which are bred for high-input management systems. The work described here aimed to study and test possible breeding strategies to produce cultivars of common bean for organic agriculture. To this purpose, crosses between a traditional Italian landrace named “Gnocchetto” and a cultivar were carried out. The F1 plants obtained were either backcrossed or self-fertilised and the obtained materials subjected to selection for quality traits at different development stages. The resulting lines were tested under four different environmental conditions for three years in order to determine their potential performance. The resulting data were analysed using a Multi-Environment Trial Analysis (MET) approach and different visualisations of the GGE biplot were generated. Furthermore, to assess the level of genetic similarity, the lines were characterised using 25 Simple Sequence Repeat (SSR) molecular markers. Results showed that the breeding approach applied allowed to select lines with the same technological and agronomic characteristics as commercially available cultivars, but with different adaptation abilities that make them suitable for organic agriculture

Vergleich genetisch diverser Brokkoli-Populationssorten mit einer F1-Hybride unter ökologischen Anbaubedingungen

Field trials were conducted for three years on an organic farm in England to assess the performance and yield variability of two synthetic sprouting broccoli populations with 4 or 8 parents respectively, along with the original landrace mother plants and a commercial F1 hybrid variety as control (Santée). In terms of total yield, Santée outperformed the other entries, but for some other traits, e.g. heading time and number of sprouts, Santée was comparable with the mean of one or more of the genetically diverse entries. Analysis of yield variability over time showed mixed results. With regard to total yield and total sprout number, variability was higher in the F1 hybrid than in the genetically diverse populations, but for other parameters such as average sprout weight and time to maturity, patterns were less clear. Using broccoli populations in commercial production will depend on acceptability of within-population variability of phenotypic traits, especially maturation time

An online toolbox for cover crops and living mulches

Cover crops and living mulches form an integral component of conservation agriculture promoting soil health and minimising external inputs. The OSCAR Project (Optimising Subsidiary Crop Applications in Rotation) aims to improve practices of conservation agriculture in farming systems across Europe. The principal output of the project is to develop a toolbox to make technical and scientific information publically available to farmers, researchers, and other stakeholders. The continually evolving toolbox is currently available online at www.covercrops.eu and will consist of three facets (1) An interactive user-fed wiki providing information on subsidiary crops species and machinery use with links to published literature. (2) A searchable database on subsidiary crops and technology. This will detail climatic and soil specific plant traits and will form a decision support tool to aid choices of subsidiary crops. (3) A discussion forum will also facilitate the exchange of information between farmers, researchers and stakeholders on conservation agricultural systems across European countries