Effect of fertilization dose and sowing density on grain-filling in different winter wheat cultivars

Multi-factor Randomized Complete Block Design (RCBD) experiment was conducted to analyze the effect of fertilization dose and sowing density on the characteristics of grain-filling in three hi-quality winter wheat cultivars (“Longjian301”, “Ningmai5” and “1R17”). Variance analysis on the three factors of fertilization dose, sowing density and cultivar was then conducted based on the fitting result of grain-filling process via Logistic Growth Equation (LGE). The results indicate that grain-filling of 3 winter wheat cultivars best fits LGE under different fertilization dose and sowing density, with an S-like breakthrough curve of slow-fast-slow trend. The levels of fertilization and sowing density influence 12 grain-filling parameters of winter wheat cultivars, with both affected parameters and degree of effect varying with cultivar type. Yields of “Longjian301” and “Ningmai5” under high sowing density and fertilization treatment are highest (4 188.09 kg·hm^-2 and 3 789.89 kg·hm^-2 respectively). Under medium fertilization and high sowing density treatment, yield of “1R17” is highest (3 018.18 kg·hm^-2) and grain-filling achieves the best state. Interaction between fertilization and sowing density is significant and apparently positive. In order to increase grain yield, fertilization dose and sowing density determination should be based on the characteristics of different wheat cultivars.