The dwarfing gene Rht15 can significantly reduce plant height and improve lodging resistance, but has some negative effects on yield traits. Rht15 is a gibberellin-responsive (GAR) dwarfing gene that causes dwarfism by blocking the Gibberellin (GA) synthesis pathway in plants, and application of exogenous GA3 can increase the plant height phenotype. The aim of this study was to investigate whether exogenous GA3 could compensate for the negative effect of Rht15 on yield while maintaining good lodging resistance. The F5, F6 and F7 lines derived from reciprocal crosses between Durox (Rht15 donor) and Langdon were used to explore the response of Rht15 to exogenous GA by comparing the effects of Rht15 dwarf lines, Rht15 dwarf lines-GA3 and tall lines on grain filling related traits, yield traits, plant height and lodging resistance traits in durum wheat. The results showed that exogenous GA3 could significantly improve the grain filling dynamics, significantly increase the maximum grain filling rate (Gmax) and the average grain filling rate (Gave), and advance the occurrence time of maximal grain-filling rate (Tmax) earlier. The 1000-kernel weight and grain yield of the Rht15 dwarf lines with-GA3 were significantly increased and were not significantly different from the tall line. Plant height and internode length of the Rht15 dwarf lines increased significantly after exogenous GA3 treatment, but were still slightly shorter than those of the tall lines. The lodging resistance of the Rht15 dwarf lines-GA3 was reduced, but still had significant advantages over the tall lines. This study provided a new idea for dwarf breeding: using plant hormones to improve the negative effects of dwarfing genes on wheat.

中文翻译：

---

外源 GA3 显著改善了硬粒小麦 Rht15 矮秆品系的灌浆过程和产量性状


矮化基因 Rht15 可以显著降低株高并提高抗倒伏性，但对产量性状有一定的负面影响。Rht15 是一种赤霉素反应性 （GAR） 矮化基因，通过阻断植物体内赤霉素 （GA） 合成途径引起侏儒症，应用外源 GA3 可增加株高表型。本研究的目的是研究外源 GA3 是否可以在保持良好倒伏抵抗性的同时补偿 Rht15 对产量的负面影响。采用 Durox （Rht15 供体） 和 Langdon 之间互惠杂交的 F5 、 F6 和 F7 品系，通过比较 Rht15 矮秆品系、Rht15 矮秆品系-GA3 和高大品系对硬粒小麦灌浆相关性状、产量性状、株高和抗倒伏性状的影响，探讨 Rht15 对外源 GA 的响应。结果表明，外源GA3能显著改善籽粒灌浆动态，显著提高最大籽粒灌浆速率（Gmax）和平均籽粒灌浆速率（Gave），提前实现最大籽粒灌浆速率（Tmax）的发生时间。添加-GA3 的 Rht15 矮秆品系的 1000 粒重和产量均显著增加，与高品系无显著差异。外源 GA3 处理后，Rht15 矮秆系的株高和节间长显著增加，但仍略短于高系。Rht15 矮秆品系-GA3 的抗倒伏性降低，但与高品系相比仍具有显著优势。这项研究为矮秆育种提供了新思路：利用植物激素来改善矮化基因对小麦的负面影响。