关键词: 玉米大豆带状复合种植, 生长调节剂, 夏玉米, 茎秆特性, 产量

Abstract:

【Objective】 This study clarified the physiological basis of the effects of growth regulators on the stem characteristics and yield of summer maize under maize-soybean strip intercropping, with the aim of providing the technical support and theoretical basis for improving the lodging resistance of summer maize and ensuring stable and high yield in the intercropping system. 【Method】 In 2023-2024, using maize variety of Denghai 605, soybean varieties of Heidou 22 and Andou 203 as test materials, under the strip intercropping pattern of 4 rows of maize and 6 rows of soybeans, six treatments were designed (CK, treatment with water; T1, 300 mg·L^-1 ethepene+0.03 mg·L^-12, 4-epibrassinolide; T2, 300 mg·L^-1 ethepene+0.03 mg·L^-1 aminosterol; T3, 300 mg·L^-1 ethylene glycol+0.03 mg·L^-1 2, 4-epibrassinolide+0.03 mg·L^-1 aminosterol; T4, 300 mg·L^-1 ethylene glycol+2 g·L^-1 chlorpyritin+ 0.03 mg·L^-1 2, 4-epibrassinolide; T5, 300 mg·L^-1 ethoxylenol+2 g·L^-1 chlorpyritin+0.03 mg·L^-1 2, 4-epibrassinolide +0.03 mg·L^-1 aminosterol) at the V7 (7-leaf) stage. The maize plants were sprayed with either water or different combinations of these growth regulators. The effects of various combination treatments on the morphology of intercropped maize plants, lignin, hemicellulose, and cellulose content in the third internode from the base, as well as on yield, were investigated. 【Result】 Compared with CK, the application of growth regulators increased the stem diameter, lignin, cellulose, and hemicellulose content in the maize third internode from the base, while reducing maize plant height and length of the third internode, thus improving the lodging resistance of intercropped maize. In addition, the growth regulators increased the leaf area index (LAI), number of ears per hectare, and ear tip length of maize, while reducing its plant height, ear length, number of kernels per ear, 1000-grain weight, and grain yield in the maize-soybean strip intercropping system. The decrease in yield was primarily due to the reduction in the number of kernels per ear and thousand kernel weight caused by the growth regulators. The T3 and T5 treatments had higher leaf area index, stem diameter, and lignin content in the third internode, with a yield reduction of 0.38%-1.53% (T3) and 1.40%-3.03% (T5), indicating that the combination treatments of ethephon, 2,4-epibrassinolide, and aminocyclopropane carboxylic acid (T3 and T5) were beneficial to maize yield formation in the intercropping system. 【Conclusion】 After the application of growth regulators, the stem diameter and lignin content of intercropped maize in the maize-soybean strip intercropping system increased, resulting in enhanced lodging resistance. Under the experimental conditions, the combination of ethephon (300 mg·L^-1), 2,4-epibrassinolide (0.03 mg·L^-1), and aminocyclopropane carboxylic acid (0.03 mg·L^-1) was found to be the most effective growth regulator formulation for improving the lodging resistance of maize stalks in the maize-soybean strip intercropping system while conducive to the stable yield of intercropping maize.

Key words: maize-soybean strip intercropping, growth regulators, summer maize, stem characteristics, yield