春玉米拔节孕穗期倒伏发生特点及内在成因分析

Root and shoot characteristics associated with lodging resistance of spring maize during the jointing-booting stage

适当提高玉米种植密度是目前挖掘我国玉米高产潜力的关键措施之一,但种植密度的提高增加了倒伏发生的风险。倒伏使玉米产量降低,品质变劣,并且给机械收获带来困难。本研究以春玉米为对象,针对玉米拔节孕穗期倒伏发生特点、抗倒伏植株和倒伏植株基部茎节及较高茎节上的次生根的相关力学特征开展研究。结果显示,调查区域内玉米倒伏严重。不同倒伏类型比较,根倒伏发生频率显著高于茎倒伏,二者分别占总数的90.4%和4.9%。根倒伏的发生以中度和重度为主,轻度倒伏发生频率较低。与不抗倒伏植株相比,抗倒伏植株基部茎节的节间直径、惯性矩以及抗弯截面系数高;同时抗倒伏植株较高茎节上的节根数量和最大拉力较倒伏植株高。

To intense the planting density of maize is one of the key factors to increase yield potential. However,higher planting density would take a risk of maize lodging,which may decrease yield and quality of maize with machine harvest problems. The jointing-booting stage is susceptible to lodging in maize,thus a field experiment was conducted to investigate root and shoot characteristics associated with resistance to strong wind-and rain-induced lodging. The results showed that experimental maize was with a heavy lodging. Root lodging was more frequently than shoot lodging,accounting for 90. 4% and 4. 9% of the total,respectively. As for root lodging,major was with middle and heavy lodging rather than light lodging. Compared with lodging maize,lodging resistant maize was with wider diameter of base internodes,higher moment of inertia and section modulus bending; also,lodging resistant maize was with more nodal roots and stronger root maximum tension in higher internodes.