Drought-adaptive traits derived from wheat wild relatives and landraces
Drought-adaptive traits derived from wheat wild relatives and landraces
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DOI：
10.1093/jxb/erl250
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发表时间：
2007-01-01
影响因子：
6.9
通讯作者：
Trethowan, Richard
中科院分区：
文献类型：
--
作者：
Reynolds, Matthew;Dreccer, Fernanda;Trethowan, Richard
在面包小麦育种中，外来亲本被用于增加等位基因多样性，通过（i）祖先基因组的种间杂交以产生所谓的合成衍生（SYN-DER）小麦，以及（ii）与源自非生物胁迫环境的地方品种种质杂交，这些地方品种种质已经从主流基因库中分离出来。固有的遗传多样性评估所包含的干旱适应地方品种与检查相比，使用DNA指纹图谱证实，一些地方品种不仅远离检查，但也显示出显着的多样性彼此之间。与轮回亲本相比，SYN-DER系的性能改善与根干重的更大总体投资无关，而是根质量向更深土壤剖面（60 cm和120 cm之间）的分配增加，并增加了从这些深度提取水分的能力。最好的墨西哥地方品种表现出优越的上级能力方面的水提取从土壤深处，以及增加浓度的可溶性碳水化合物在茎开花后不久。虽然可以认为，从这些性状的过度表达推断理论产量增加是值得怀疑的，因为补偿机制可能在起作用，但事实仍然是，生理性状之间的机械或遗传联系在很大程度上仍未建立。与此同时，性状信息正被用于根据有用的压力适应性状与在选定的后代中实现加性基因作用的可能性的理论结合来进行战略杂交。与优良对照品种杂交的候选品种包括鉴定的地方品种，其在干旱下显示出相对高的生物量，并结合有利的生理性状表达，如茎碳水化合物、水提取特性和蒸腾效率。
Exotic parents are being used to increase allelic diversity in bread wheat breeding through (i) interspecific hybridization of the ancestral genomes to produce so-called synthetic derived (SYN-DER) wheat, and (ii) crossing with landrace accessions, originating in abiotically stressed environments, that have become isolated from mainstream gene pools. Evaluation of the inherent genetic diversity encompassed by drought-adapted landraces compared with checks using DNA fingerprinting confirmed that some landraces were not only distant from checks but also showed significant diversity among each other. Improvement in performance of SYN-DER lines compared with recurrent parents was not associated with a larger overall investment in root dry weight, but rather an increased partitioning of root mass to deeper soil profiles (between 60 cm and 120 cm) and increased ability to extract moisture from those depths. The best Mexican landraces showed superior ability in terms of water extraction from soil depth, as well as increased concentration of soluble carbohydrates in the stem shortly after anthesis. Although it can be argued that inferring theoretical yield gains from the over-expression of any of these traits is questionable, since compensatory mechanisms may be at work, the fact remains that mechanistic or genetic linkages among physiological traits remain largely un-established. In the meantime, trait information is being used to make strategic crosses based on the theoretical combination of useful stress-adaptive traits with the possibility of realizing additive gene action in selected progeny. Candidates for crossing with elite check cultivars include landraces identified that showed relatively high biomass under drought combined with favourable expression of physiological traits such as stem carbohydrates, water extraction characteristics, and transpiration efficiency.