Genomic approaches to increasing resilience in oilseed rape seedling establishment in the Yangtze River basin

点击翻译按钮获取中文摘要

In China poverty is present predominantly in rural regions where annual incomes still depend heavily on returns from crops. A key cause of poverty is financial stress resulting from poor yields, which increasingly are affected by stochastic occurrence of extreme weather, particularly drought and flooding. The Yangtze River Basin is a globally-significant rapeseed growing area, using so-called semi-winter varieties drilled in the hot and seasonally dry month of September and harvested the following year. Around 14 million hectares are under drought stress (20 times the entire UK planting area), and drought during germination and seedling establishment is particularly detrimental to yields. Climate change is threatening rapeseed growing in the Yangtze River Basin because it is both increasing September temperatures, and increasing the frequency and duration of droughts. These conditions are hostile for seed germination and seedling growth, and can even induce dormancy and prevent germination altogether. To continue cultivation it will therefore be important to produce new varieties with enhanced tolerance to heat and drought stress during germination and early seedling growth.In the modern genomic era the availability of large genotyped populations is greatly accelerating the process of linking traits to individual genes and markers. The principal bottleneck for gene discovery has become our ability to perform smart high throughput phenotyping under relevant conditions for revealing crop properties. This proposal aims to exploit a new phenotyping platform at JIC which automates seed germination, root and shoot growth measurements and increases the frequency of scoring from the traditional once per day to once per hour. We aim to optimise conditions on the platform to mimic the temperature regime and water potential of the Yangtze River catchment in September and screen oilseed rape varieties for germplasm with enhanced ability to germinate and establish effectively under stressful conditions. We will then use statistical tools to identify genes and markers underlying the beneficial traits, and the identity of these genes will be used to form and test hypotheses for the underlying biological mechanisms. We aim to use one European population and one Chinese population derived from a F1 rapeseed variety developed by our partners in the Oilseed Crop Research Institute (OCRI), Wuhan, that will shortly be released onto the Chinese market. This use of elite close-to-market germplasm maximises our chances of translating initial discoveries into new varieties in the shortest possible time window.In order to understand whether improved material has a chance of mitigating climate change impacts it is also necessary to produce a theoretical framework that links crop establishment performance to weather variation. To do this we will produce hydrothermal time models of rapeseed establishment, modelling existing varieties and our best germplasm under Chinese conditions and test the models in a set of field trials. This will pave the way for a larger study aiming to understand for how long and under what emissions scenarios rapeseed cultivation can continue with current practises in the Yangtze River Basin.