当前和未来的条件下干旱胁迫和性状对玉米产量的影响

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全球气候变化预计将增加温度，改变降雨的地理分布格局，增加极端气候事件的发生频率。这些变化有可能改变作物要经历的干旱胁迫的时间和幅度。本研究采用了新的作物水分胁迫的分类方法，首先，研究了欧洲玉米作物所经历的干旱胁迫模式的布局和频率，以及相应的产量分布；其次，在当前和未来的气候条件下，确定不同干旱胁迫的类型下散粉吐丝同步性、成熟期、籽粒数等育种性状对产量的影响。在历史条件下，低或无水分胁迫的类型发生最频繁最高，达约40 ％，而其他三种作物在生育后期经历的胁迫类型的发生频率都在20％左右。这四种水分胁迫模式也是2050年的气候条件下的主要类型。低或无水分胁迫的类型未来的频率大约减少了约15％，而灌浆期严重缺水类型从18％升高到25％。尽管如此， CO2浓度升高对作物生长的影响缓和气候变化对产量造成的不利影响。在低或无干旱胁迫的季节类型下，散粉吐丝同步对产量的影响最大；在严重的灌浆早期干旱胁迫类型下，早熟对产量的影响最大。对干旱胁迫季节模式进行分类，允许我们更加深入地理解在不同的天气条件下性状变化对作物产量的影响。研究表明：尽管严重干旱胁迫类型的发生频率未来将会增加，作物如果暴露于同一干旱胁迫的类型下，在目前和将来的气候条件下，性状变化对产量的影响十分类似。这些研究结果对玉米育种有着重要影响，并对研究作物对环境胁迫的遗传和生理响应有着重要意义。

作者：Matthew T. Harrison, François Tardieu, Zhanshan Dong, Carlos D. Messina， Graeme L. Hammer

杂志：Global Change Biology, 2014, 20(3):867–878

Characterizing drought stress and trait influence on maize yield under current and future conditions

Global climate change is predicted to increase temperatures, alter geographical patterns of rainfall and increase the frequency of extreme climatic events. Such changes are likely to alter the timing and magnitude of drought stresses experienced by crops. This study used new developments in the classification of crop water stress to first characterize the typology and frequency of drought-stress patterns experienced by European maize crops and their associated distributions of grain yield, and second determine the influence of the breeding traits anthesis-silking synchrony, maturity and kernel number on yield in different drought-stress scenarios, under current and future climates. Under historical conditions, a low-stress scenario occurred most frequently (ca. 40%), and three other stress types exposing crops to late-season stresses each occurred in ca. 20% of cases. A key revelation shown was that the four patterns will also be the most dominant stress patterns under 2050 conditions. Future frequencies of low drought stress were reduced by ca. 15%, and those of severe water deficit during grain filling increased from 18% to 25%. Despite this, effects of elevated CO2 on crop growth moderated detrimental effects of climate change on yield. Increasing anthesis-silking synchrony had the greatest effect on yield in low drought-stress seasonal patterns, whereas earlier maturity had the greatest effect in crops exposed to severe early-terminal drought stress. Segregating drought-stress patterns into key groups allowed greater insight into the effects of trait perturbation on crop yield under different weather conditions. We demonstrate that for crops exposed to the same drought-stress pattern, trait perturbation under current climates will have a similar impact on yield as that expected in future, even though the frequencies of severe drought stress will increase in future. These results have important ramifications for breeding of maize and have implications for studies examining genetic and physiological crop responses to environmental stresses.