Department of Agronomy and Plant Breeding, Faculty of Agriculture, University of Kurdistan, P. O. Box 416, Sanandaj, Iran.
Department of Plant Breeding, Justus Liebig University, IFZ Research Centre for Biosystems, Land Use and Nutrition, Heinrich-Buff-Ring 26-32, Giessen, 35392, Germany.
Theor Appl Genet. 2019 May;132(5):1295-1307. doi: 10.1007/s00122-019-03299-z. Epub 2019 Feb 10.
Although Ae. tauschii has been extensively utilised for wheat breeding, the D-genome-containing allopolyploids have largely remained unexploited. In this review, we discuss approaches that can be used to exploit the D genomes of the different Aegilops species for the improvement of bread wheat. The D genome of allohexaploid bread wheat (Triticum aestivum, 2n = AABBDD) is the least diverse of the three wheat genomes and is unarguably less diverse than that of diploid progenitor Aegilops tauschii (2n = DD). Useful genetic variation and phenotypic traits also exist within each of the wheat group species containing a copy of the D genome: allopolyploid Aegilops species Ae. cylindrica (2n = DDCC), Ae. crassa 4x (2n = DDXX), Ae. crassa 6x (2n = DDXXDD), Ae. ventricosa (2n = DDNN), Ae. vavilovii (2n = DDXXSS) and Ae. juvenalis (2n = DDXXUU). Although Ae. tauschii has been extensively utilised for wheat breeding, the D-genome-containing allopolyploids have largely remained unexploited. Some of these D genomes appear to be modified relative to the bread wheat and Ae. tauschii D genomes, and others present in the allopolyploids may also contain useful variation as a result of adaptation to an allopolyploid, multi-genome environment. We summarise the genetic relationships, karyotypic variation and phenotypic traits known to be present in each of the D genome species that could be of relevance for bread wheat improvement and discuss approaches that can be used to exploit the D genomes of the different Aegilops species for the improvement of bread wheat. Better understanding of factors controlling chromosome inheritance and recombination in wheat group interspecific hybrids, as well as effective utilisation of new and developing genetics and genomics technologies, have great potential to improve the agronomic potential of the bread wheat D genome.
尽管 Ae. tauschii 已被广泛用于小麦育种，但包含 D 基因组的异源多倍体在很大程度上尚未得到利用。在这篇综述中，我们讨论了可以用来利用不同的 Aegilops 物种的 D 基因组来改良普通小麦的方法。异源六倍体普通小麦（Triticum aestivum，2n = AABBDD）的 D 基因组是三个小麦基因组中最少多样化的，而且无疑比二倍体祖先 Ae. tauschii（2n = DD）的 D 基因组多样化程度低。在含有 D 基因组副本的每个小麦族物种中，也存在有用的遗传变异和表型特征：异源多倍体 Ae. cylindrica（2n = DDCC）、Ae. crassa 4x（2n = DDXX）、Ae. crassa 6x（2n = DDXXDD）、Ae. ventricosa（2n = DDNN）、Ae. vavilovii（2n = DDXXSS）和 Ae. juvenalis（2n = DDXXUU）。尽管 Ae. tauschii 已被广泛用于小麦育种，但包含 D 基因组的异源多倍体在很大程度上尚未得到利用。其中一些 D 基因组似乎相对于普通小麦和 Ae. tauschii D 基因组有所改变，而其他存在于异源多倍体中的基因组也可能由于适应异源多倍体、多基因组环境而包含有用的变异。我们总结了每个 D 基因组物种中存在的遗传关系、核型变异和表型特征，这些特征可能与普通小麦改良有关，并讨论了可以用来改良普通小麦的不同 Aegilops 物种的 D 基因组的方法。更好地了解控制小麦族种间杂种染色体遗传和重组的因素，以及有效利用新的和发展中的遗传学和基因组学技术，有可能提高普通小麦 D 基因组的农艺潜力。
