Triticum (Aegilops) tauschii in the natural and artificial synthesis of hexaploid wheat
Triticum (Aegilops) tauschii in the natural and artificial synthesis of hexaploid wheat
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DOI：
10.1071/ar07352
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发表时间：
2008-01-01
影响因子：
--
通讯作者：
Lagudah, E. S.
中科院分区：
文献类型：
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作者：
Halloran, G. M.;Ogbonnaya, F. C.;Lagudah, E. S.
本文讨论了粗粒小麦（Triticumtauschii（Ae.）tauschii）以及野生和栽培形式的四倍体小麦。一个概括提出了可能的基因型和表型状态的新出现的天然六倍体和可能的杂交从哪里产生的路径。T. tauschii对小麦改良的影响表明，从T. tauschii并没有在其与小麦的自然和农业联系中出现。这一点已经在比较研究中得到证实，揭示了T。与六倍体小麦的D基因组进行了比较，并提出了一个扩大T. tauschii基因库概念的例子。tauschii的变异用于小麦改良，并提出了二级基因库的概念，以包括T. tauschii，因为它出现在几种多倍体形式的“草小麦”中。可能的分化的生长习性形式，条件是春化（即。e. vrn）基因在六倍体小麦合成中的作用，以及这些基因在六倍体小麦中的相互作用。推测在四倍体-六倍体混合体（可能是早期农业小麦作物的常见组成）中，以及在新石器时代农业向西北欧和中亚的高纬度、寒冷环境的传播中，生长习性分化对六倍体的产量贡献和存活具有重要意义。tauschii的独特的碾磨和面包制作性能的六倍体小麦进行了讨论，根据罗马的识别，其更接近的要求，发酵面包制作相比，四倍体小麦。T. tauschii的小麦进化似乎已经大大延迟（约6500年），因为六倍体小麦直到罗马时代才得到单独的关注和栽培，从那里它逐渐流行起来，最终达到其目前的卓越地位。tauschii的小麦改良，利用传统和遗传分析和当代基因组工具，主张。后一种方法是特别重要的数量性状在植物表型的广泛分歧，从六倍体小麦的代表。
An account is given of the possible time(s) and place( s) of the origin of hexaploid wheat from natural hybridisation between Triticum tauschii (Ae. tauschii) and both wild and cultivated forms of tetraploid wheat. A recapitulation is presented of the likely genotypic and phenotypic status of the newly arisen natural hexaploid and the likely path of hybridisation from whence it arose. Recent substantial contributions of T. tauschii to wheat improvement indicate the likelihood that introgession en masse from T. tauschii has not occurred throughout its natural and agricultural associations with wheat. This has been substantiated in comparative studies revealing higher levels of genetic variation in T. tauschii compared with the D genome of hexaploid wheat.A case is made for a widening of the concept of the gene pool of T. tauschii for wheat improvement and the notion of a secondary gene pool is proposed to include variation in T. tauschii as it occurs in several polyploid forms of 'grass Triticum'. The likely differentiation of growth habit forms, conditioned by vernalisation (i. e. vrn) genes, in hexaploid wheat synthesis, including the interaction of these genes in hexaploid wheat, is discussed. It is speculated that growth habit differentiation was of significance to the hexaploid's yield contribution and survival in tetraploid-hexaploid mixtures ( likely to be a common constitution of wheat crops of early agriculture), and in the Neolithic spread of agriculture to the higher latitude, and colder environments of NW Europe and central Asia.The significance of the contribution of T. tauschii to the unique milling and bread-making properties of hexaploid wheat is discussed in the light of Roman discernment of its closer fulfilment of the requirements of leavened bread-making compared with tetraploid wheat. The significance of the contribution of T. tauschii to the evolution of wheat appears to have been much delayed ( by similar to 6500 years) in that hexaploid wheat did not receive singular attention and cultivation until during the Roman era, from whence it gradually rose in popularity to eventually achieve its current pre-eminent status.Continuing systematic evaluation of genetic variation in both the primary and secondary gene pools of T. tauschii for wheat improvement, using both conventional and genetic analysis and contemporary genomic tools, is advocated. The latter approach is particularly important for quantitative traits in the light of wide divergence in plant phenotype of their representatives from that of hexaploid wheat.