多效唑对杂交中稻不同密肥群体产量和抗倒伏性的影响

为探究高产稻田中防止倒伏发生的早期诊断技术,2015-2016年,以大面积推广的杂交中稻高产新品种蓉18优1015为试验材料,设计3因素完全因子试验,研究不同密肥群体下喷施多效唑对稻谷产量和抗倒伏性的影响。结果表明,随着施氮量和移栽密度的增加,稻谷产量提高,植株抗倒力下降,以施氮量150 kg·hm^-2和移栽密度18.75 万穴·hm^-2的产量较高。不同密肥群体下施用多效唑对产量和植株抗倒伏性有显著影响,施用多效唑后植株抗倒力增强,但产量因穗粒数下降而减少。不同密肥处理下施用多效唑对产量影响各异。于水稻最高苗期施用多效唑使植株重心高度、弯曲力矩、倒伏指数显著降低,折断弯矩则明显提高,穗粒数平均减少5.24~7.87粒。多效唑对产量的影响表现为低施氮量下因穗粒数减少而减产;中施氮量下产量差异不显著;高施氮量下植株未倒伏、籽粒灌浆结实正常,因结实率和千粒重高而增产。综上所述,肥力水平和施氮量高的稻田于最高苗期施用多效唑有利于水稻产量提高和控制后期倒伏。本研究为指导大面积水稻高产稳产提供了科学依据。

Effects of Paclobutrazol on Yield and Lodging Resistance With Different Dense-fertilizer Population in Mid-season Hybrid Rice

In order to explore the early diagnostic techniques for lodging prevention in high-yielding paddy fields, a new high-yielding hybrid rice variety "Rong 18 You 1015", which was widely popularized, was used to design a three-factor complete factor experiment in 2015-2016, and to study the effects of Paclobutracol spraying on rice yield and lodging resistance under different dense-fertilizer population. The results showed that with the increase of nitrogen application rate and transplanting density, rice yield increased and plant lodging resistance decreased. The yield of 150 kg hm^-2 N application and 187.5 million holes hm^-2 transplanted was higher. The application of Paclobutrazol in different dense-fertilizer population had significant effects on yield and lodging resistance of plants. After application of paclobutrazol, plant resistance increased and yield decreased with the decrease of grain number per panicle. However, the effect of Paclobutrazol on yield was different under different dense-fertilizer treatments. The application of Paclobutrazol at the highest seedling stage of rice significantly reduced the height of plant center of gravity, bending moment and lodging index, but significantly increased the breaking strength Average number of grains per panicle decreased by 5.24-7.87 grains. The effects of Paclobutrazol on yield were as follows: yield decreased with the decrease of grain number per panicle under low nitrogen application rate; yield difference was not significant under medium nitrogen application rate; plant lodging was not observed under high nitrogen application rate; grain filling was normal; and yield was increased due to high seed setting rate and 1 000-grain weight. In summary, the application of Paclobutrazol at the highest seedling stage in paddy fields with high fertility level and nitrogen application rate is conducive to the improvement of rice yield and the control of late lodging.