Unravelling the effect of winter warming on flowering time, flower fertility and crop yield

据预测，气候变化将使西欧的冬天变暖，比工业化前的温度高出2摄氏度到8摄氏度。众所周知，温暖的冬季对多年生作物的产量产生了负面影响，冬季花蕾的不完全冷却导致花蕾断裂较弱，开放的花朵较少：事实上，冬季寒冷的需求通常决定了有利于种植温带多年生作物的气候区域。在欧洲，高产的主要可耕作作物以冬季一年生作物的形式种植，也就是说，它们在夏末或秋季播种，并要求冬季降温以促进向春季开花的过渡，这一过程被称为春化。然而，我们最近发现，对于冬季油菜作物来说，春化过程实际上发生在中秋，紧随其后的是花的快速过渡和深秋花蕾的形成。我们还表明，花芽发育阶段对应于田间温暖的冬季温度对次年夏季英国产量有实质性负面影响的时期。这就提出了一个问题，即冬季一年生作物是否像多年生植物一样，要求花蕾冷却，以最大限度地提高次年春季的作物表现，以及气候变化是否正在降低气候地区的产量，因为气候地区的冬季寒冷是不能保证的。这里提供的初步数据为这一假设提供了令人信服的支持。本研究综合运用生理学、分子遗传学、育种和基因组学方法，探讨了暖冬对冬季油菜产量产生负面影响的机理，特别是在早冬花序发育的暖季易出现暖季的地区。然后，我们将使用基因组育种的方法来克隆油菜的基因，这种基因可能会在温暖的冬季的生长季节提供更有弹性的产量，利用我们之前发现的一个品种，我们发现该品种在花序发育期间对温度变化没有显著的产量反应。通过将这些性状导入优良种质，我们可以确定气候变化适应性遗传学是否可以与现代高产品系相结合，产生适合现代育种计划的品系。

Climate change is predicted to warm winters in western Europe between 2C and 8C above pre-industrial temperatures this century. It is well known that warm winters negatively affect the yield of perennial crops where incomplete chilling of flower buds in winter leads to weak bud break and fewer open flowers: indeed the requirement for winter chill generally determines the climate zones favourable for cultivation of temperate perennial crops. In Europe high yielding major arable crops are grown as winter annuals, that is they are sown in late summer or autumn and have a requirement for winter chilling to promote the transition to flowering in spring, a process known as vernalisation. However, we have recently shown that for the winter oilseed rape crop this vernalisation process actually happens in mid-autumn, followed quickly by the floral transition and formation of a flower bud in late autumn. We also showed that the stage of flower bud development corresponds to a period in the field where warm winter temperatures have a substantial negative affect on the UK yields the following summer. This raises the question of whether like perennials, winter annual crops have a requirement for chilling of flower buds to maximise crop performance in the following spring, and whether climate change is reducing yields in climate zones where winter chilling is not guaranteed. The preliminary data provided here provides compelling support for this hypothesis. Most specifically, we show that chilling of flower buds promotes earlier bud break in spring, and that winter warming of flower buds leads to production flowers in spring with obvious abnormalities and poor fertility.This proposal uses a combination of physiology, molecular genetics, breeding and genomic approaches to understand the mechanism by which warm winters negatively impacts winter oilseed rape yields, especially in climate zones prone to warm spells during early winter when inflorescence development is taking place, such as the United Kingdom and China. Then we will use genomic approaches to breeding to clone genes in oilseed rape that may confer more resilient yields in growing seasons with warm winters, exploiting our previous discovery of one variety that we show has no significant yield response to temperature variation during inflorescence development. By introgressing these traits into elite germplasm we can determine whether climate change resilient genetics can be combined with modern high yielding lines to generate lines suitable for modern breeding programmes.