Foliar application uniconazole enhanced lodging resistance of hybrid indica rice by altering basal stem quality under poor light stress

Abstract

Poor light stress causes lodging risks in hybrid indica rice (Oryza sativa L.) in Sichuan Basin, China. However, the effective way of improving lodging resistance of hybrid indica rice by plant regulation strategy under poor light stress has not yet been investigated. A 2‐yr field study, comparing the three foliar application uniconazole rates under normal light and shading condition, was conducted to determine the lodging resistance and its physiological mechanism by using two hybrid rice varieties (Yuxiang203 [YX203] and Cliangyouhuazhan [CLYHZ]). The results showed that shading significantly decreased grain yield, but, increased lodging index (LI) due to poor stem breaking strength (M). Also, shading increased the non‐structural carbohydrates (NSC), but reduced structural carbohydrate (SC), especially for lignin in basal culm and thus, weakened the stem stiffness. Grain yield was first increased, and then declined with increasing foliar uniconazole rates. And, LI decreased sharply owing to improvement of M while reduction of bending moment by whole plant (WP). Larger section modulus (SM) of YX203 and higher bending stress (BS) of CLYHZ were contributed to higher M. Correlation analysis showed that M was significantly correlated with culm diameter, culm wall thickness and SC content for YX203, and that with SC content for CLYHZ, respectively. The results indicated that foliar application of uniconazole increased lodging resistance of hybrid indica rice for larger M and SC accumulation in basal stem. Uniconazole foliar application at 40 mg L–1 can increase lodging resistance while maintaining grain yield of hybrid indica rice in the Sichuan Basin, China.

An R2R3‐MYB network modulates stem strength by regulating lignin biosynthesis and secondary cell wall thickening in herbaceous peony

“…The lodging and bending caused by insufficient stem strength seriously affect the yield and quality of plants, and reduce their commercial value. The thickening and development of the secondary cell wall provides stronger mechanical support for plant stems (Shah et al., 2019; Zhang, Yao, et al., 2022; Zhong et al., 2019). Thus, understanding the transcriptional regulatory network of secondary cell wall thickening and development in is crucial for lodging or bending resistance.…”

“…It is worth noting that secondary cell walls also provide mechanical strength for structural support. Stem strength was significantly positively correlated with stem secondary wall thickness in crops such as rice ( Oryza sativa ; Zhang, Yao, et al., 2022) and wheat ( Triticum aestivum ; Khan et al., 2020), and in ornamental plants such as herbaceous peony ( Paeonia lactiflora Pall. ; Zhao, Shi, et al., 2020).…”

“…Paeonia lactiflora is one of the commercially important ornamental species that is usually used for weddings as a high‐grade cut flower. Similar to crops such as rice, wheat and maize, whose yield and quality are limited worldwide due to lodging (an important agronomic trait; Khan et al., 2020; Yang, Geng, et al., 2022; Zhang, Yao, et al., 2022), bending of the stems of P. lactiflora due to lack of mechanical support reduces its cut‐flower quality and commercial value. The lodging and stem strength are dependent on the lignin deposited in the plant secondary cell walls (Tang et al., 2022; Zhao, Luan, et al., 2020; Zhao, Luan, et al., 2022).…”

Management of Seeding Rate and Nitrogen Fertilization for Lodging Risk Reduction and High Grain Yield of Mechanically Direct-Seeded Rice under a Double-Cropping Regime in South China

“…Because lodging can result in lower grain yields, reduced grain quality, more difficult mechanical harvesting, lower harvest efficiency, and increasing production costs, it is one of the most important factors influencing DSR grain yield potential [2][3][4]. Previous studies have shown that lodging can be caused by many internal and external factors, including rice variety, wind, rain, planting patterns, seeding rates, N fertilization approach, light, any phytohormones [5][6][7][8][9][10].…”

“…Presently, N fertilization recommendations for DSR focus on fertilizer type; the fertilizer rate or ratio, especially coupled with SR, is less well-researched. Additionally, excessive N application not only causes serious environmental problems such as soil acidification and water eutrophication [16,17], but also increases crop lodging risk [5][6][7][8]10]. Farmers employing a DSR approach often combine high SR with high N fertilization rates, both of which result in higher lodging risk.…”