Geng Wenjie, Sun Zhichao, Ren Baizhao, Ren Hao, Zhao Bin, Liu Peng, Zhang Jiwang
State Key Laboratory of Crop Biology, College of Agronomy, Shandong Agricultural University, Tai'an 271018, China.
Plants (Basel). 2022 Aug 26;11(17):2219. doi: 10.3390/plants11172219.
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 (L), 75,000 plants ha (M) and 90,000 plants ha (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. At the time, the lodging percentage and grain yield were 12.2% and 11,137.5 kg ha, 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.
增加种植密度是提高玉米产量的有效途径，但高种植密度往往会导致倒伏问题。本试验旨在研究增加种植密度对夏玉米茎倒伏抗性和籽粒产量的影响，并探讨喷施乙烯利对密植夏玉米茎秆和产量特性的影响。选用夏玉米杂交种浚单20（XD20）作为试验材料，在60000株/公顷（低密度，L）、75000株/公顷（中密度，M）和90000株/公顷（高密度，H）三种不同种植密度下，于玉米生长的BBCH 17期（BASF、拜耳、汽巴 - 嘉基和赫斯特联合制定的物候期标准）喷施清水（对照，CK）或乙烯利（E），以探索协同提高茎倒伏抗性和籽粒产量的可能性。本试验结果表明，密植夏玉米的重心高度显著增加，茎粗、维管束面积和数量显著减少，单位节间干重显著降低，从而削弱了茎秆表皮穿刺强度和弯曲性能，导致倒伏率显著增加。喷施乙烯利后，穗位高度显著降低，叶片叶绿素含量（SPAD值）和冠层透光率增加；然后，单位长度节间干重增加，茎秆表皮穿刺强度和弯曲性能增强，从而显著降低倒伏率并提高籽粒产量。相关性分析进一步表明，倒伏率与茎粗、维管束面积和数量以及茎秆弯曲性能显著负相关，但与籽粒产量没有强相关性。这表明协同提高茎倒伏抗性和籽粒产量并不矛盾。在试验条件下，种植密度为90000株/公顷时喷施乙烯利的效果最为显著。此时，倒伏率和籽粒产量分别为12.2%和11137.5千克/公顷，与对照处理相比，倒伏率降低了44.6%，籽粒产量提高了8.0%。科学的化学调控可以显著提高密植夏玉米的茎倒伏抗性和籽粒产量。
