粒重对氮素的响应及其与子粒灌浆参数的相关与通径分析

连续两年采用正交设计，研究了大喇叭口期追施氮肥、开花期浇水、不同氮肥施用量以及施用时期对不同品种粒重的影响效应。结果表明：品种自身的遗传特性是导致粒重差异的主要因素，高淀粉玉米品种对氮素的需求量高于普通玉米，粒重对氮肥施用量的反应较氮肥施用时期敏感。Logistic方程拟合表明，处理间单粒重的差异主要在授粉40 d之后，受处理方式影响幅度较大的3个灌浆特征参数为缓增期灌浆速率、最大灌浆速率和快增期灌浆速率，较小的3个特征参数为灌浆持续期、缓增持续期和最大灌浆速率出现时间。相关及通径分析表明，粒重主要受平均灌浆速率的直接影响，较高的平均灌浆速率是获得高粒重的前提，而平均灌浆速率提高的根本在于提高渐增期灌浆速率；灌浆持续期对粒重的直接影响效应非常小，其对粒重的影响主要是通过其他灌浆参数间接实现。

Response of Grain Weight to Nitrogen and Correlation and Path Analysis on Grain Filling Parameters

Effects of N fertilizer application at floret differentiating, irrigation at flowering, rate and timing of N fertilizer application on grain weight by orthogonal design in two years. The results showed that the genetic character was the key factors influencing on grain weight. The requirement for N fertilizer of high-starch corn was higher than that of normal corn. The sensitivity of grain weight to nitrogen application amount was higher than that to nitrogen application period. The grain-filling processes of different treatments were modeled with Logistic equation, which showed that the difference of grain weight among the treatments was mainly occurred at 40 days after pollination. But for grain filling parameters, the change scale of different treatments meet the fact that slight-increase period filling rate, max filling rate and Fast-increase period filling rate were much higher than filling duration, duration of slight-increase period and occurrence time of maximal. Filling rate, correlation and path analysis showed that the direct effect of mean filling rate on grain weight was significantly higher than filling duration, which mainly indirect affect the grain weight by slow-increase period filling rate. However, the root of increased in mean filling rate was to increase slow-increase period filling rate.