Spraying Ethephon Effectively Increased Canopy Light Transmittance of Densely Planted Summer Maize, Thus Achieving Synergistic Improvement in Stalk Lodging Resistance and Grain Yield

Abstract

Increasing planting density is an effective way to improve maize yield, but high plant populations often cause a lodging problem. This experiment was conducted to investigate the effect of increasing planting density on stalk lodging resistance and grain yield, and to explore the effects on stalk and yield properties of spraying ethephon in densely planted summer maize. The summer maize hybrid, Xundan20 (XD20), was used as experimental material. It was grown by spraying water (CK) or ethephon (E) at BBCH (BASF, Bayer, Ciba-Geigy and Hoechst) 17 under three different planting densities of 60,000 plants ha−1 (L), 75,000 plants ha−1 (M) and 90,000 plants ha−1 (H) in order to explore the possibility of synergistic improvement in stalk lodging resistance and grain yield. The results from this experiment suggested that the gravity center height of densely planted summer maize was significantly increased, the stem diameter, area and number of vascular bundles were significantly decreased and the dry weight per unit internode was significantly decreased, thereby weakening the stalk rind penetration strength and bending performance, resulting in a significant increase in lodging percentage. The ear height was significantly decreased and the SPAD (soil and plant analysis development) and canopy light transmittance were increased after spraying ethephon; then, the internode dry weight per unit length was increased and the stalk rind penetration strength and bending performance were enhanced so as to significantly reduce the lodging percentage and increase the grain yield. The correlation analysis further showed that lodging percentage was significantly negatively correlated with stem diameter, area and number of vascular bundles and stalk bending performance, but there were no strong relationships with grain yield. This suggested that the synergistic improvement in stalk lodging resistance and grain yield was not contradictory. Under the experiment conditions, the effect of spraying ethephon was most significant when the planting density was 90,000 plants ha−1. At the time, the lodging percentage and grain yield were 12.2% and 11,137.5 kg ha−1, which were decreased by 44.6% and increased by 8.0% compared with the control treatment. Scientific chemical regulation could significantly improve the stalk lodging resistance and grain yield of densely planted summer maize.

The Effect of Plant and Row Configuration on the Growth and Yield of Multiple Cropping of Soybeans in Southern Xinjiang, China

“…Therefore, the number of nodes on the main stem is one of the important indexes in the process of soybean seed testing. Some scholars have shown that the number of main stem nodes decreases with the increase in density due to the serious deterioration of individual nutrition, light, and growth space after the exceeding of a certain density [29]. In this experiment, under the conditions of the M2 treatment, the number of main stem nodes of the H2 treatment was the highest, reaching 11.1, which was 3.74% higher than that of the H1 and H3 treatments.…”

“…Reducing the planting density can significantly increase the stem diameter, but when the planting density is too high, the change in stem diameter is not obvious. This may be due to the high planting density, the fierce competition for nutrients and space between plants, and the death of some plants because of weak competitiveness; so, the change in soybean stem diameter is small [28,29]. The H1M1 treatment had the largest stem diameter, indicating that the H1M1 treatment had the best effect on the growth of soybean stem diameter and was the most conducive to the growth of soybean stem diameter and the better shaping of the soybean plant type.…”

“…The leaf area index determines the productivity of crops and affects the interaction between the surface and the atmosphere, and it is closely related to canopy photosynthesis, transpiration, and productivity [25,29]. Studies have shown that the LAI increases with the increase in density [9,14].…”

UV-B irradiation-activated E3 ligase GmILPA1 modulates gibberellin catabolism to increase plant height in soybean

“…Plant height is an important feature of plant ideotypes. The application of semi dwarf varieties has significantly improved crop yield by increasing the planting density and the lodging resistance 1 , 2 . The gains in grain productivity during the Green Revolution were a direct consequence of optimal plant height 3 .…”