Genes and QTLs controlling inflorescence and stem branch architecture in Leymus (Poaceae: Triticeae) wildrye

Grass inflorescence and stem branches show recognizable architectural differences among species. The inflorescence branches of Triticeae cereals and grasses, including wheat, barley, and 400–500 wild species, are usually contracted into a spike formation, with the number of flowering branches (spikelets) per node conserved within species and genera. Perennial Triticeae grasses of genus Leymus are unusual in that the number of spikelets per node varies, inflorescences may have panicle branches, and vegetative stems may form subterranean rhizomes. Leymus cinereus and L. triticoides show discrete differences in inflorescence length, branching architecture, node number, and density; number of spikelets per node and florets per spikelet; culm length and width; and perimeter of rhizomatous spreading. Quantitative trait loci controlling these traits were detected in 2 pseudo-backcross populations derived from the interspecific hybrids using a linkage map with 360 expressed gene sequence marker...禾本科植物的花序与茎分枝在不同物种间存在可区分的形态结构差异。小麦族（Triticeae）谷类作物与草本植物（包括小麦、大麦以及400~500个野生种）的花序分枝通常收缩为穗状结构，其每节的开花分枝（小穗，spikelets）数目在物种及属内保持恒定。赖草属（Leymus）的多年生小麦族草本植物则具有独特的性状特征：其每节小穗数目存在变异，花序可具圆锥花序分枝，且营养茎可形成地下根状茎（rhizomes）。灰赖草（Leymus cinereus）与L. triticoides在花序长度、分枝结构、节数与密度、每节小穗数及每小穗小花（florets）数、秆（culm）的长宽，以及根状茎扩展范围等性状上均存在显著差异。研究人员通过包含360个表达基因序列标记（expressed gene sequence marker）的遗传连锁图谱（linkage map），在由上述种间杂种（interspecific hybrids）衍生的2个伪回交群体（pseudo-backcross populations）中，检测到控制这些性状的数量性状位点（Quantitative trait loci）。