State Key Laboratory of Crop Stress Biology for Arid Areas and College of Agronomy, Northwest A&F University, Yangling, Shaanxi, China.
PLoS One. 2013 Apr 26;8(4):e62285. doi: 10.1371/journal.pone.0062285. Print 2013.
Opportunities exist for replacing reduced height (Rht) genes Rht-B1b and Rht-D1b with alternative dwarfing genes, such as the gibberellin-responsive gene Rht12, for bread wheat improvement. However, a comprehensive understanding of the effects and mode of action of Rht12 is lacking. In the present study, the effects of Rht12 were characterized by analyzing its effects on seeding vigour, seedling roots, leaf and stem morphology, spike development and carbohydrate assimilation and distribution. This was carried out in the four genotypes of F2:3 lines derived from a cross between Ningchun45 and Karcagi (12) in two experiments of autumn sowing and spring sowing. Rht12 significantly decreased stem length (43%∼48% for peduncle) and leaf length (25%∼30% for flag leaf) while the thickness of the internode walls and width of the leaves were increased. Though the final plant stature was shortened (40%) by Rht12, the seedling vigour, especially coleoptile length and root traits at the seedling stage, were not affected adversely. Rht12 elongated the duration of the spike development phase, improved the proportion of spike dry weight at anthesis and significantly increased floret fertility (14%) in the autumn sowing experiment. However, Rht12 delayed anthesis date by around 5 days and even the dominant Vrn-B1 allele could not compensate this negative effect. Additionally, grain size was reduced with the ability to support spike development after anthesis decreased in Rht12 lines. Finally, grain yield was similar between the dwarf and tall lines in the autumn sowing experiment. Thus, Rht12 could substantially reduce plant height without altering seeding vigour and significantly increase spikelet fertility in the favourable autumn sowing environment. The successful utilization of Rht12 in breeding programs will require careful selection since it might delay ear emergence. Nonetheless, the potential exists for wheat improvement by using Rht12.
存在将矮化基因 Rht-B1b 和 Rht-D1b 替换为替代矮化基因（如赤霉素反应基因 Rht12）的机会，用于改良面包小麦。然而，对 Rht12 的作用及其作用模式缺乏全面的了解。本研究通过分析 Rht12 对种子活力、幼苗根、叶片和茎形态、穗发育以及碳水化合物同化和分配的影响，来表征 Rht12 的作用。这项研究是在两个秋季和春季播种实验中，对源自宁春 45 和 Karcagi（12）杂交的 F2:3 系的四个基因型进行的。Rht12 显著降低了茎长（花梗 43%∼48%）和叶长（旗叶 25%∼30%），而节间壁的厚度和叶片的宽度增加。尽管 Rht12 使最终植株高度缩短（40%），但幼苗活力，特别是幼苗期的胚芽鞘长度和根特性，没有受到不利影响。Rht12 延长了穗发育阶段的持续时间，提高了开花期穗干重的比例，并显著增加了秋季播种实验中的小花育性（14%）。然而，Rht12 使抽穗期延迟了大约 5 天，即使显性 Vrn-B1 等位基因也无法弥补这种负面影响。此外，Rht12 系的穗发育后期支持能力下降，导致粒重减小。最终，在秋季播种实验中，矮秆和高秆系的籽粒产量相似。因此，Rht12 可以在不改变种子活力的情况下显著提高小穗育性，在有利的秋季播种环境中大幅度降低植株高度。在选育计划中成功利用 Rht12 需要仔细选择，因为它可能会延迟穗的出现。尽管如此，利用 Rht12 仍有可能改善小麦。
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