Optimizing application strategies of prohexadione-calcium·uniconazole composite regulator to improve lodging resistance and grain yield in rice cultivation in East China

IF 5.6 1区农林科学 Q1 AGRONOMY

Field Crops Research Pub Date : 2025-04-26 DOI:10.1016/j.fcr.2025.109931

Dengke Ma , Yimin Ding , Yifan Liu , Lin Du , You Mo , Ali Dai , Junyan Xu , Dalu Gu , Liusheng Duan , Weiming Tan

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引用次数: 0

Abstract

Context or problem

Rice (Oryza sativa L.) is a major staple crop worldwide. Yet, its grain yield is frequently constrained by lodging, which disrupts the canopy structure, reduces photosynthetic efficiency, lowers grain quality, and hampers mechanical harvesting. The application of plant growth regulators (PGRs) can mitigate lodging risks; however, the individual use of uniconazole and prohexadione-calcium presents certain limitations, such as panicle development issues and high costs, respectively.

Objective or research question

This study aimed to determine the optimal application timing and concentration of a composite PGR, prohexadione-calcium·uniconazole (PCU), to enhance stem traits and grain yield components, thereby improving rice lodging resistance and yield.

Methods

A two-year field experiment was conducted to assess the effects of different PCU concentrations (90, 120, and 180 g ha⁻¹) applied at two critical growth stages: the tillering stage (I) and the jointing stage (when the first elongating internode of 50 % of plants reached 1 cm, designated as II). A water-treated control (PCU0) was included. The study evaluated plant height, stem characteristics, lodging index (LI), endogenous hormone levels, and grain yield parameters.

Results

Foliar application of PCU at 120 g ha⁻¹ during the jointing stage (PCU120-Ⅱ) significantly reduced the LI by 25.0–36.5 % and increased grain yield by 8.1–9.3 %. Compared with PCU0-Ⅱ, PCU120-Ⅱ markedly shortened the basal internode length while increasing the culm diameter and culm wall thickness. Additionally, PCU120-Ⅱ significantly reduced endogenous gibberellin A₃ (GA₃) levels in the second internode (I-2), leading to a reduction in plant height and center of gravity height. Conversely, the elevated endogenous zeatin content promoted cell division in stem tissues, contributing to increased culm wall thickness in the basal internodes. Furthermore, PCU120-Ⅱ enhanced the accumulation of key cell wall components, including cellulose and lignin, thereby strengthening stem rigidity. According to the random forest importance ranking, culm wall thickness, lignin content, culm diameter, and cellulose content emerged as key traits for breeding lodging-resistant rice. Moreover, PCU120-Ⅱ significantly increased both the number of panicles per unit area and grain weight, which were the primary contributors to the observed yield improvement.

Conclusions

Applying PCU at 120 g ha⁻¹ during the jointing stage is the optimal strategy for improving rice lodging resistance and grain yield. This effect is achieved through modifications in stem morphology, hormonal balance, and grain yield components.

Implications or significance

This study elucidates the mechanism by which the novel composite PGR, PCU, enhances rice lodging resistance and optimizes its application strategies in terms of timing and dosage. The findings provide a promising approach to improving rice production efficiency and yield stability, offering valuable insights for both agronomic management and breeding programs.

查看原文本刊更多论文

优化丙己酮-钙·单康唑复合调节剂在华东地区水稻抗倒伏和增产中的应用策略

水稻（Oryza sativa L.）是世界范围内的主要粮食作物。然而，其籽粒产量经常受到倒伏的限制，这破坏了冠层结构，降低了光合效率，降低了籽粒质量，阻碍了机械收获。植物生长调节剂（pgr）的应用可以降低倒伏风险；然而，单康唑和丙己二酮钙的单独使用分别存在一定的局限性，如穗发育问题和成本高。目的或研究问题本研究旨在确定复合PGR - prohexadione-calcium·uniconazole （PCU）的最佳施用时间和浓度，以改善水稻茎秆性状和籽粒产量成分，从而提高水稻抗倒伏能力和产量。方法采用2年的田间试验，评价不同浓度（90、120、180 g ha⁻¹）在分蘖期(I)和拔节期（当50% %的植株第一个伸长节间达到1 cm时，称为II）的施用效果。研究评估了植株高度、茎秆特性、倒伏指数、内源激素水平和籽粒产量参数。结果拔节期叶面施PCU120 g ha - 1 （PCU120-Ⅱ）可显著降低土壤LI 25.0 ~ 36.5% %，增产8.1 ~ 9.3 %。与PCU0-Ⅱ相比，PCU120-Ⅱ显著缩短了茎秆基部节间长度，增加了茎秆直径和茎壁厚度。此外，PCU120-Ⅱ显著降低了第二节间（I-2）内源赤霉素A3 （GA3）水平，导致株高和重心高度降低。相反，内源玉米素含量的增加促进了茎组织的细胞分裂，导致基部节间茎壁厚度增加。此外，PCU120-Ⅱ增强了关键细胞壁成分（包括纤维素和木质素）的积累，从而增强了茎的刚性。根据随机森林重要性排序，茎秆壁厚、木质素含量、茎秆直径和纤维素含量是选育抗倒伏水稻的关键性状。此外，PCU120-Ⅱ显著增加了单位面积的穗数和粒重，这是观察到的产量提高的主要原因。结论拔节期施用120 g ha−1的PCU是提高水稻抗倒伏和籽粒产量的最佳策略。这种效果是通过改变茎形态、激素平衡和籽粒产量成分来实现的。本研究阐明了新型复合PGR PCU增强水稻抗倒伏能力的机理，并从施用时机和用量方面优化了其施用策略。这些发现为提高水稻生产效率和产量稳定性提供了一种有希望的方法，为农艺管理和育种计划提供了有价值的见解。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Field Crops Research 农林科学-农艺学

CiteScore

9.60

自引率

12.10%

发文量

307

审稿时长

46 days

期刊介绍： Field Crops Research is an international journal publishing scientific articles on: √ experimental and modelling research at field, farm and landscape levels on temperate and tropical crops and cropping systems, with a focus on crop ecology and physiology, agronomy, and plant genetics and breeding.