Tasmanian Institute of Agriculture, University of Tasmania, Private Bag 1375, 7250, Prospect, TAS, Australia.
CSIRO Agriculture and Food, 4067, St Lucia, QLD, Australia.
BMC Plant Biol. 2022 Jun 24;22(1):305. doi: 10.1186/s12870-022-03694-7.
Carbohydrate accumulation of photosynthetic organs, mainly leaves, are the primary sources of grain yield in cereals. The flag leaf plays a vital role in seed development, which is probably the most neglected morphological characteristic during traditional selection processes.
In this experiment, four flag leaf morphological traits and seven yield-related traits were investigated in a DH population derived from a cross between a wild barley and an Australian malting barley cultivar. Flag leaf thickness (FLT) showed significantly positive correlations with grain size. Four QTL, located on chromosomes 1H, 2H, 3H, and 5H, respectively, were identified for FLT. Among them, a major QTL was located on chromosome 3H with a LOD value of 18.4 and determined 32% of the phenotypic variation. This QTL showed close links but not pleiotropism to the previously reported semi-dwarf gene sdw1 from the cultivated barley. This QTL was not reported before and the thick leaf allele from the wild barley could provide a useful source for improving grain yield through breeding.
Our results also provided valuable evidence that source traits and sink traits in barley are tightly connected and suggest further improvement of barley yield potential with enhanced and balanced source and sink relationships by exploiting potentialities of the wild barley resources. Moreover, this study will provide a novel sight on understanding the evolution and development of leaf morphology in barley and improving barley production by rewilding for lost superior traits during plant evolution.
光合作用器官（主要是叶片）的碳水化合物积累是谷类作物产量的主要来源。旗叶在种子发育中起着至关重要的作用，而在传统选择过程中，这可能是最被忽视的形态特征。
本实验在野生大麦和澳大利亚麦芽大麦品种杂交衍生的 DH 群体中，研究了四个旗叶形态特征和七个与产量相关的特征。旗叶厚度（FLT）与籽粒大小呈显著正相关。在 1H、2H、3H 和 5H 染色体上分别鉴定到四个与 FLT 相关的 QTL。其中，一个主要的 QTL 位于 3H 染色体上，LOD 值为 18.4，决定了 32%的表型变异。该 QTL 与先前报道的来自栽培大麦的半矮秆基因 sdw1 紧密连锁但无表型多效性。该 QTL 以前没有报道过，野生大麦的厚叶等位基因可以通过育种提供一个有用的来源来提高籽粒产量。
我们的研究结果还提供了有价值的证据，表明大麦的源性状和汇性状紧密相连，并通过挖掘野生大麦资源的潜力，进一步提高大麦的产量潜力，改善源和汇之间的平衡关系。此外，本研究将为理解大麦叶片形态的进化和发育提供新的视角，并通过重新引入在植物进化过程中丢失的优良特性来提高大麦的产量。
