Effects of Different Plant Growth Regulators on the Grain Filling Characteristics and Grain Weight in Wheat

Huaimai 25,a semi-winter wheat cultivar,was used to study the effect of different plant growth regulators on the grain filling characteristics and grain weight in wheat.The grain filling process of wheat with different plant growth regulators treatments was fitted by Logistic equation in order to explain the changes of grain dry matter,grain filling rate and grain weight.The correlations between grain filling parameters and grain weight in wheat were discussed by correlation analysis.The results showed that the increment of grain dry matter in wheat with the different plant growth regulators treatments presented aScurve change.The grain filling process could be extremely well described by the logistic model,since the determination coefficients of Logistic equation were between 0.998and 0.999,which achieved a significant level.Correlation analysis indicated that there was a significantly positive correlation between Tmax,T,Rand grain weight.Furthermore,the correlation between grain weight and Twas greater than R.Additionally,the grain weight positively correlated withgrain filling rate of gradual increasing-stage(R1),filling duration of rapid increasing-stage(T2)and slow increasing-stage(T3)significantly.The fitted maximum 1000-grain weight consisted with the change of 1000-grain weight of strong grain at the end of filling.JF and GA3treatments enhanced the final 1000-grain weight significantly,while Paclobutrazol,Cobalt nitrate and Ethephon treatments significantly reduced the final 1000-grain weight.Therefore,the exogenous JF and GA3treatments at the initial-heading stage of wheat could increase grain filling rate of gradual increasing-stage(R1),extended filling duration of rapid increasing-stage(T2)and slow increasing-stage(T3),improved grain filling parameters,finally enhanced the grain weight.