Department of Plant Sciences, University of California, Davis, CA 95616, USA.
J Hered. 2012 May-Jun;103(3):426-41. doi: 10.1093/jhered/esr152. Epub 2012 Feb 29.
It is widely believed that hexaploid wheat originated via hybridization of hulled tetraploid emmer with Aegilops tauschii (genomes DD) and that the nascent hexaploid was spelt, from which free-threshing wheat evolved by mutations. To reassess the role of spelt in the evolution of Triticum aestivum, 4 disomic substitution lines of Ae. tauschii chromosome 2D in Chinese Spring wheat were developed and one of them was used to map the Tg locus, which controls glume tenacity in Ae. tauschii, relative to simple sequence repeat (SSR) and expressed sequence tag loci on wheat chromosome 2D. The segregation of SSR markers was used to assess the presence of Tg alleles in 11 accessions of spelt, both from Europe and from Asia. Ten of them had an inactive tg allele in the D genome and most had an active Tg allele in the B genome. This is consistent with spelt being derived from free-threshing hexaploid wheat by hybridization of free-threshing wheat with hulled emmer. It is proposed that the tetraploid parent of hexaploid wheat was not hulled emmer but a free-threshing form of tetraploid wheat.
人们普遍认为，六倍体小麦是由皮燕麦四倍体与节节麦（基因组 DD）杂交形成的，而初生的六倍体是斯佩耳特小麦，其通过突变进化为自由脱粒小麦。为了重新评估斯佩耳特小麦在普通小麦进化中的作用，我们培育了中国春小麦中 2D 号染色体上的 4 个节节麦二体异附加系，并利用其中一个系将控制节节麦颖壳韧性的 Tg 基因座定位到小麦 2D 号染色体上的简单重复序列（SSR）和表达序列标签（EST）基因座上。SSR 标记的分离用于评估 11 个来自欧洲和亚洲的斯佩耳特小麦品种中 Tg 等位基因的存在情况。其中 10 个在 D 基因组中具有无活性的 tg 等位基因，大多数在 B 基因组中具有活性 Tg 等位基因。这与斯佩耳特小麦是由自由脱粒六倍体小麦与皮燕麦杂交形成的自由脱粒小麦衍生而来的观点一致。因此，六倍体小麦的四倍体亲本不是皮燕麦，而是四倍体小麦的自由脱粒形式。
