Ohta Shoji
Professor emeritus, Department of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Matsuoka-Kenjojima, Eiheiji, Yoshida, Fukui 910-1195, Japan.
Breed Sci. 2022 Jun;72(3):198-212. doi: 10.1270/jsbbs.21060. Epub 2022 Jun 29.
Seed dormancy, a vital strategy for wild plant species to adapt to an unpredictable environment in their natural habitats, was eliminated from cereals during the domestication process. Intraspikelet differences in grain size and seed dormancy have been observed in wild emmer wheat. To elucidate the genetic variation of these intraspikelet differences and to determine their genetic control, grain weight ratio (first florets/second florets) (GWR), germination rate, and germination index (GI) were analyzed in 67 wild and 82 domesticated emmer wheat accessions, as well as F hybrids, F populations, and F-F populations derived from reciprocal crosses between wild and domesticated lines. Only the grains on the first florets of two-grained spikelets in wild accessions had varying degrees of dormancy with GI ranging from 0 to 1, which positively correlated with their GWR. This implies that wild emmer populations comprised genotypes with varying degrees of dormancy, including nondormant genotypes. According to segregations observed in F populations, the intraspikelet grain weight difference was controlled by two independently inherited loci. Furthermore, low-GWR populations with low or high GI values could be selected in F and F generations, implying that the major loci associated with dormancy might be independent of intraspikelet grain weight difference.
种子休眠是野生植物物种在其自然栖息地适应不可预测环境的重要策略，在驯化过程中从谷类作物中消失了。在野生二粒小麦中观察到小穗内粒重和种子休眠存在差异。为了阐明这些小穗内差异的遗传变异并确定其遗传控制，对67份野生和82份驯化二粒小麦种质以及F1杂种、F2群体以及野生和驯化品系正反交产生的F1-F2群体的粒重比（第一小花/第二小花）（GWR）、发芽率和发芽指数（GI）进行了分析。野生种质中双粒小穗第一小花上的籽粒仅具有不同程度的休眠，GI范围为0至1，且与它们的GWR呈正相关。这意味着野生二粒小麦群体包含不同休眠程度的基因型，包括非休眠基因型。根据在F2群体中观察到的分离情况，小穗内粒重差异由两个独立遗传的位点控制。此外，在F2和F3代中可以选择具有低或高GI值的低GWR群体，这意味着与休眠相关的主要位点可能独立于小穗内粒重差异。
