Intercropping and mixed cropping of maize varieties enhances flowering-stage heat tolerance and grain yield

Li Shuyan; Li Junling; Dong Wanlin; Pang Xinyue; Li Hongping; Shao Ruixin; Liu Tianxue

doi:10.13522/j.cnki.ggps.2025226

Abstract：[Objective]Summer maize is sensitive to heat stress during its flowering stage.This paper explored the efficacy of intercropping and mixing various maize cultivars in improving their tolerance to heat stress during the flowering stage and enhancing population grain yield.[Method]A field experiment was conducted in 2017 in Xuchang City,Henan Province.The Dedan 5,a high-yield variety with strong heat tolerance,was intercropped or mix-cropped with four matching varieties:Zhengdan 958,Xianyu 335,Weike 702,and Denghai 605.During the experiment,we measured plant height,ear height,ear morphological traits,yield components,individual yield,and population grain yield.[Result]The plant height of Dedan 5 was significantly reduced when intercropped with Zhengdan 958 or mixe-cropped with the other four varieties,but markedly increased when intercropped with Xianyu 335.Change in ear height was consistent with the change of plant height in all treatments.Intercropping or mix-cropping did not induce significant alteration in yield components of Dedan 5,but significantly improved the phenotypic traits of other matching varieties.Compared with monoculture,intercropping and mixed-cropping significantly increased the ear length of Xianyu 335 and Weike 702 by 9.3%-18.0%,while reducing the bald tip length of Zhengdan 958 and Weike 702 by 0.1-0.9 cm.Intercropping with Weike 702,intercropping and mix-cropping with Xianyu 335,and mix-cropping with Zhengdan 958 and Denghai 605 increased the kernel number per ear of Dedan 5 by 8.5%-20.8%.Except for the Dedan 5-Xianyu 335 intercropping,intercropping or mix-cropping with Dedan 5 increased the 100-kernel weight of other varieties by 4.2%-5.4%.Overall,intercropping and mix-cropping increased the yield of the matching varieties by 2.1%-21.9%.Intercropping or mix-cropping Dedan 5 with Weike 702 and Xianyu 335,and mix-cropping Dedan 5 with Denghai 605 reached a land equivalent ratio of 1.1.[Conclusion]Intercropping Dedan 5 with Weike 702 or Xianyu 335,and mix-cropping Dedan 5 with Weike 702,Xianyu 335 and Denghai 605 effectively improved maize population yield.These combinations can be used as optimized cultivation practices to enhance flowering-stage heat tolerance and increase population yield of summer maize production in the region.