FACCE ERA-NET+: Securing yield stability of Brassica crops in changing climate conditions

Extreme and variable climate conditions are expected to become more frequent worldwide with projected climate change. European agriculture is facing the crucial challenge of adapting crop productivity to climate change and will need the development of crops with increased resilience to abiotic stress factors triggered by climate change. Crop yield stability is dependent on the response of key developmental and growth processes to stress conditions. Delayed or accelerated flowering time, alteration of root architecture and growth, and disruption of pod-shattering are common responses displayed by crops exposed to high temperature or drought conditions associated to climate change. SYBRACLIM will evaluate the impact of these environmental factors on developmental and physiological processes directly influencing the yield of oilseed rape, Europe's premium oilseed crop. We will also shed light on the genetic and molecular bases of the tolerance of different rapeseed varieties to increasing temperature and drought stress. The SYBRACLIM consortium is multidisciplinary and includes both commercial breeding companies and leading research groups with high complementarities that cover the fields of genetics, genomics, physiology, breeding and agronomy in Brassica crops along with modeling of crop performance under climate change. Rapeseed is one of the world's most important sources of high-quality vegetable oils for human nutrition and biofuels, and particularly in Europe is also a major contributor to vegetable protein diets for ruminant livestock. SYBRACLIM will implement a multidisciplinary and innovative approach to characterize the phenotypic changes related to flowering time, root development and pod shattering in response to increased temperature and drought, and to analyse the productivity (yield, oil and protein content) in rapeseed varieties. We will also use genomics-assisted selection of stress-tolerance traits in controlled environments and field trials. The relationship between performance and variability of the studied developmental processes will allow us to identify new genetic traits associated with adaptation and use them to design stress tolerant rapeseed crops by complementary plant breeding and biotechnology strategies. Finally, we will integrate all these environmental, phenotypic and productivity data in models that will assess the performance of rapeseed varieties across different climate conditions. These models will be applied to simulate expected performance of rapeseed traits under projected climate change scenarios. Because breeders need decades to develop new varieties, this approach will enable anticipatory breeding for early development of germplasm carrying the necessary genetic variation to cope with climatic changes. SYBRACLIM will provide tools to allow the farmers to design better strategies for adapting cropping systems to climate change, contributing to secure yield of Brassica crops in Europe.

The main objective of SYBRACLIM is to create new tools that contribute to improve the performance of oilseed rape under the variable conditions imposed by projected climatic change. The focus of this innovative program will be to secure sustainable yield of this economically important European crop by gaining a deeper insight into developmental traits that have a direct impact on productivity. By understanding the mechanisms that oilseed rape plants use to integrate developmental programmes with responses to high temperature and low water availability, SYBRACLIM will provide the basis on which more efficient production of oilseed rape can be achieved. The wide range of expertise present in SYBRACLIM will allow us to evaluate the effect of increasing temperature and water deficiency on flowering time, root architecture and growth, pod-shattering and seed yield. SYBRACLIM will also generate molecular (genomic and transcriptomic profiles) and metabolic data that will help us to identify the genetic determinants responsible for the adaptation of rapeseed to a changing environment. These data will be associated with yields and phenotypes in predictive models that will incorporate climatic parameters and agricultural management practices. Finally, we will use simulation modelling to suggest ideotypes of oilseed rape cultivars better suited to cope with variable climate. Therefore, the collaboration of experimental and theoretical scientists together with plant breeders within the SYBRACLIM multidisciplinary project will provide an outstanding opportunity to generate the knowledge necessary to optimise performance of oilseed rape and develop the tools to secure stable yield of this crop under stress conditions related to climate change.

Resilience to changes in climate conditions is one of the most critical factors for ensuring high crop yields with adverse weather conditions that could have potentially devastating effects. For example, in the UK approximately one third of the oilseed rape acreage planted in the autumn of 2012 was ploughed in mainly due to poor establishment caused by unfavourable weather in the first months following sowing, and only about half of the remaining crop provided decent yield. Although a particularly bad year, the poor performance in 2012/13 underlines the need for varieties with improved yield stability under suboptimal conditions. In France during the past 40 years, genetic gain for oilseed rape yield has increased by +0.46 q/ha/year until 1990 but only +0.18 q/ha/year after 1990. This slowdown is due to a combination of factors: 1) an adaptation of agricultural practices with reduced inputs for an optimum economic profit, 2) the global climatic change, and 3) the bulk of breeding efforts primarily emphasized on oil quality, with a lesser extent to yield improvement and its stability under adverse environmental conditions. By advancing our understanding of the mechanisms of how oilseed rape plants integrate developmental and growth processes in response to temperature and drought, this project will provide the basis on which more efficient production of oilseed rape can be achieved. Furthermore, when the enhanced knowledge obtained from these studies will be translated into programmes for crop improvement, it will directly contribute to improve food security by increasing crop yields and stability under unfavourable climatic conditions. The developmental and physiological processes of critical relevance in this context are those that affect root architecture, silique growth, seed setting and seed filling, all of which contribute to determining yields. For example, the knowledge on how pods from oilseed rape develop under different environmental scenarios will likely lead to ways of controlling seed loss caused by pod shatter in oilseed rape. Pod shatter leads to an average annual loss of 15-20% seeds (but can be >70% under extreme weather circumstances). Assuming our discoveries are bred into commercial crops in the EU, an increase in oilseed rape yield of 15 per cent would equate to an increase in farm-gate value of Euro2bn based on 2011 prices if implemented across the EU-28. In SYBRACLIM we will also perform a comprehensive phenotyping of two other developmental processes, flowering time and root development, with large impact on crop performance and consequently high economic relevance. Flowering time is a well-documented indicator of the ecological effect of climate change. Temperatures greater than 27C during flowering resulted in seed yield losses up to 58% in rapeseed. Flowering time is normally accelerated under high temperatures whereas root development may be delayed. Maximum daily temperatures will exceed this threshold in some of the rapeseed growing regions. Therefore, enhanced knowledge on how rapeseed floral transition and root architecture are differentially regulated by changing environmental conditions will help the development of cultivars with better performance under heat stress associated with climate change.