The potential of EDAH in promoting kernel formation and grain yield in summer maize

Context or problem

Enhancing crop yield by increasing planting density has long been a widely accepted agricultural practice. However, high-density planting is prone to problems, such as increased intraspecific competition. Growth regulators are often used to mitigate the challenges posed by heightened intraspecific competition and the negative effects on kernel setting and final yield associated with dense planting. However, the exact mechanisms of these growth regulators in kernel formation remain unclear.

Objective

The aim of this study was to investigate the regulatory effects of EDAH on spike differentiation and fertilization in summer maize.

Methods

Denghai605 (DH605) and Xianyu335 (XY335) were used as the experimental materials at two planting densities (D1:60,000 plants ha⁻¹ and D2:90,000 plants ha⁻¹), and EDAH was sprayed at different stages (6th, 9th, and 12th leaf stages). Spike differentiation characteristics, grain-filling characteristics, SPAD, stalk cross-sectional area, and yield were determined.

Results

Spraying EDAH at a high planting density (D2) significantly increased the yield of maize, especially after spraying at 9th leaf stage (S2), and the yields of XY335 and DH605 increased by 21.55 % and 12.64 %, respectively, compared with CK. Spraying EDAH accelerated the ear differentiation process and fertilization rate, with the percentage of male tasseling increasing from 3.29 % to 10.33 % and the percentage of female silking increasing by 4.12–15.98 %. The fertilization rate of florets increased by 4.39–7.77 %, and the number of grains per ear increased significantly. In addition, EDAH spraying increased the SPAD value by 1.67–7.70 %, and the cross-sectional area of the third internode increased by 7.83–26.22 %.

Conclusion

Spraying EDAH to promote ear differentiation and optimize physiological characteristics is beneficial for improving the grain-filling rate and ultimately increasing yield. The most significant increase in yield was achieved by spraying EDAH at the 9th leaf stage and was particularly pronounced in the lodging-susceptible variety (XY335).

Implications or significance

These results provide new insights into high-efficiency cultivation methods for varieties with high yield potential but poor density tolerance.