Whole plant responses, key processes, and adaptation to drought stress: the case of rice
Whole plant responses, key processes, and adaptation to drought stress: the case of rice
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DOI：
10.1093/jxb/erl101
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发表时间：
2007-01-01
影响因子：
6.9
通讯作者：
Li, Z-K.
中科院分区：
文献类型：
--
作者：
Lafitte, H. R.;Guan Yongsheng;Li, Z-K.
大多数为灌溉条件开发的高产水稻品种，包括广泛种植的低地品种IR 64，对干旱胁迫非常敏感。这限制了它们在水稻种植环境中的应用，因为在生长季节存在缺水的风险。利用水高地群体进行的绘图研究提供的关于干旱条件下产量变化的遗传基础的信息有限。同时提高和理解水稻耐旱性的一种方法是产生回交群体，在管理的胁迫环境中选择上级品系，然后评估所选品系的哪些特征不同于轮回亲本。这种方法是用IR64，使用一系列的耐受和敏感品种作为供体亲本。在13个广泛收缩的水环境中测得的所选品系的产量普遍大于IR64，但基因型环境效应很大。预期在IR 64和选择的品系之间变化的性状是植株高度，因为许多供体不是半矮秆类型，和成熟度，因为预期在终末胁迫环境中的选择有利于早熟。在这些实验中，发现一些在高地干旱下表现更好的品系确实比IR 64高，但也可以鉴定出在干旱下具有良好产量的较短品系。在试验中，干旱胁迫发展在以前淹没（低地）领域，高度与性能无关。随着选择的进行，成熟度几乎没有变化。IR64和选择的回交系之间的其他显着差异是在他们的反应施加阿坝和乙烯在温室实验中在营养阶段和在叶片卷曲观察到的慢性高地胁迫下在该领域。这些意见是一致的假设，适应性应对干旱可以有效地提高性能在广泛的水环境。结果表明，在干旱条件下，通过回交选择，IR64的产量有显著提高。在干旱不频繁但在某些年份严重的目标环境中，具有更大耐旱性的改良IR 64将是农民的一个有价值的选择。
Most high-yielding rice cultivars developed for irrigated conditions, including the widely grown lowland variety IR64, are highly susceptible to drought stress. This limits their adoption in rainfed rice environments where there is a risk of water shortage during the growing season. Mapping studies using lowland-by-upland rice populations have provided limited information about the genetic basis of variation in yield under drought. One approach to simultaneously improve and understand rice drought tolerance is to generate backcross populations, select superior lines in managed stress environments, and then evaluate which features of the selected lines differ from the recurrent parent. This approach was been taken with IR64, using a range of tolerant and susceptible cultivars as donor parents. Yields of the selected lines measured across 13 widely contracting water environments were generally greater than IR64, but genotype-by-environment effects were large. Traits expected to vary between IR64 and selected lines are plant height, because many donors were not semi-dwarf types, and maturity, because selection in a terminal stress environment is expected to favour earliness. In these experiments it was found that some lines that performed better under upland drought were indeed taller than IR64, but that shorter lines with good yield under drought could also be identified. In trials where drought stress developed in previously flooded (lowland) fields, height was not associated with performance. There was little change in maturity with selection. Other notable differences between IR64 and the selected backcross lines were in their responses to applied ABA and ethylene in greenhouse experiments at the vegetative stage and in leaf rolling observed under chronic upland stress in the field. These observations are consistent with the hypothesis that adaptive responses to drought can effectively allow for improved performance across a broad range of water environments. The results indicate that the yield of IR64 under drought can be significantly improved by backcrossing with selection under stress. In target environments where drought is infrequent but significant in certain years, improved IR64 with greater drought tolerance would be a valuable option for farmers.