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Abstract：
Establishment of seedlings is a key factor in achievement of uniform field stands and, consequently, stable yields. Under Mediterranean conditions, soil moisture in the upper layer is limited and seedlings may be exposed to frequent dehydration events. The presence of the Reduced height (Rht)-B1b and Rht-D1b semi-dominant dwarfing alleles results in insensitivity to gibberellin (GAI) and, hence, poor emergence from deep sowing. Introduction of alternative dwarfing genes and, thereby, preservation of the gibberellin response (GAR) and coleoptile length, contributes to better emergence from deep sowing. Initially 47 wheat cultivars carrying different Rht alleles were screened for their ability to emerge from deep sowing, and then 17 of them were selected for detailed physiological characterization in the field. The modern wheat lines containing GAI alleles showed significantly lower percentages of emergence from deep sowing than the GAR lines, i.e., 52 and 74%, respectively. Differences in early developmental stages were associated with grain yield, as indicated by a reduction of 37.3% in the modern GAI cultivars. Our results demonstrate the potential of alternative dwarfing genes for improving seedling establishment and grain yields in Mediterranean-like environments.
摘要：
幼苗的建立是实现均匀田间林分的关键因素，因此,稳定的产量。在地中海条件下，上层的土壤水分有限，幼苗可能会频繁脱水。高度降低（Rht）-B1b和Rht-D1b半显性矮化等位基因的存在导致对赤霉素（GAI）不敏感，因此，从深播中脱颖而出。引入替代矮化基因，因此，保持赤霉素反应（GAR）和胚芽鞘长度，有助于更好地从深播中脱颖而出。最初，筛选了47个携带不同Rht等位基因的小麦品种，以确定它们从深播中出现的能力，然后选择其中的17个用于该领域的详细生理表征。含有GAI等位基因的现代小麦品系显示出深播种的出苗百分比明显低于GAR品系，即，52％和74％，分别。早期发育阶段的差异与谷物产量有关，现代GAI品种减少了37.3%。我们的结果证明了替代矮化基因在地中海样环境中改善幼苗建立和谷物产量的潜力。
