Most high-yielding, semi-dwarf wheat (Triticum aestivum L.) grown around the world contains either Rht1 or Rht2 genes. The success of these high-yielding cultivars is greatest in the most productive farming environments but provide marginal benefits in less favorable growing conditions such as shallow soils and low-precipitation dryland farming. Further, growing evidence suggests semi-dwarf genes not only affect early seedling growth but limit grain yield, especially under abiotic stress conditions. There are 23 other reduced-height mutants reported in wheat, most of which have not been functionally characterized. We evaluated these mutants along with their parents for several traits affecting seedling emergence, early seedling growth, and photosynthetic efficiency. Two- to seven-fold differences in coleoptile length, first leaf length, root length, and root angle were observed among the genotypes. Most of the mutations had a positive effect on root length, while the root angle narrowed. Coleoptile and first leaf lengths were strongly correlated with emergence. A specialized deep planting experiment identified Rht5, Rht6, Rht8, and Rht13 with significantly improved seedling emergence compared to the parent. Among the mutants, Rht4, Rht19 and Rht12 ranked highest for photosynthetic traits while Rht9, Rht16 and Rht15 performed best for early seedling growth parameters. Considering all traits collectively, Rht15 showed the most promise for utilization in marginal environments followed by Rht19 and Rht16. These wheat mutants may be useful for deciphering the underlying molecular mechanisms of understudied traits in breeding programs in arid and semi-arid regions where deep planting is practiced. This article is protected by copyright. All rights reserved.

中文翻译：

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表征影响幼苗生长过程中非生物胁迫和光合作用的性状的低矮小麦突变体

世界各地种植的大多数高产半矮小麦（Triticum aestivum L.）都含有 Rht1 或 Rht2 基因。这些高产栽培品种在生产力最高的农业环境中取得的成功最大，但在较不利的生长条件（例如浅层土壤和低降水量的旱地农业）中提供边际效益。此外，越来越多的证据表明，半矮化基因不仅影响早期幼苗生长，而且限制谷物产量，尤其是在非生物胁迫条件下。在小麦中还报告了 23 种其他高度降低的突变体，其中大部分尚未进行功能表征。我们评估了这些突变体及其父母的几个影响幼苗出现、幼苗早期生长和光合效率的性状。胚芽鞘长度、第一叶长度、在基因型中观察到根长和根角。大多数突变对根长有积极影响，而根角变窄。胚芽鞘和第一片叶的长度与出苗密切相关。一项专门的深植实验发现，与亲本相比，Rht5、Rht6、Rht8 和 Rht13 的出苗率显着提高。在突变体中，Rht4、Rht19 和 Rht12 的光合性状排名最高，而 Rht9、Rht16 和 Rht15 的早期幼苗生长参数表现最好。综合考虑所有特征，Rht15 在边缘环境中的利用潜力最大，其次是 Rht19 和 Rht16。这些小麦突变体可能有助于破译深耕的干旱和半干旱地区育种计划中未被研究的性状的潜在分子机制。本文受版权保护。版权所有。