Effects Of Plant Density On Lodging Resistance Of Different Maize Hybrid

Increasing planting density appropriately is one of the important ways to increase maize yield,and lodging is the main limiting factor for increasing population density of maize.Five hybrids of Denghai 661?DH661?,Denghai 618?DH618?,Denghai 605?DH605?,Xianyu 335?XY335?,Zhengdan 958?ZD958?were selected in this study.Six densities of 15,000,45,000,60,000,75,000,90,000 and 105,000 plants hm^-2 were set up.In this paper the effects of density on lodging resistance and agronomic traits of stems were studied.Results are as follows:1.Among the five hybrids,DH618 has the best lodging resistance,and ZD958 has the worst lodging resistance.The results showed that the XY335 anti-reverse ability was moderate in the all test hybrids,but it actually fell over a large area at 75000 hm^-2.This reason requires analysis of the plant type and population lodging resistance.2.The plant lodging force increases with the increase of the inclination angle and begins to decrease after reaching the peak and then the plant breaks.The toughness of DH618increases with the increase of density.The toughness and density of other hybrids are less correlated.The lodging resistance of different hybrids decreases with increasing density and is more variable at low density.3.The plant height of maize increases with the increase of density,the increasing trend gradually slows down,and increases to peak when it begins to decrease.The effect of density on the ear position height is more obvious.The effect of density on ear position is due to the increase of the number of nodes in high density and the elongation between nodes.The lodging resistance ability of maize decreased with the increase of ear position of plant.The high ear position had a great influence on the resistance to inversion of the same hybrid,but the comparison between hybrids,the high ear position and high plant height to a certain extent did not mean that the variety had poor lodging resistance ability.4.The fresh weight of the plant had little effect on the lodging resistance ability.The development of stalk continued after the spitting period,and the effect of density on the dry matter of the upper stem of the spikelet was positively correlated,and the dry matter of the lower stem of 45,000 plant ha^-1 density of all cultivars was greater than 15,000 plant ha^-1.The stem of the plant was given priority in the low density,and the stalk of 45,000 plant ha^-1 could maintain continuous development,possibly because there were not enough nutrients at high density to supply stalk development and ear development at the same time.Stems of lodging resistance hybrids develop earlier.5.With the increase of density,the density of vascular bundle increased gradually,and the thickness of cortical thickness and thick wall cells of vascular bundle decreased.The non-lodging resistance hybrid shows a higher sensitivity to density.The stem mechanical tissue development of lodging resistance hybrid is better than that of non-lodging resistance,thus showing high tightness and inversion resistance.