Alleviation of terminal drought stress in wheat by foliar application of zinc and manganese

In order to study the effect of drought stress and foliar application of micronutrients on agronomical properties of wheat cultivar Sirvan, the experiments were carried out at the Agricultural Research Field of Islamic Azad University of Kermanshah during the 2015-16 and 2016 -17 growing seasons. The experiments were performed in a split-plot format in a randomized complete-block design based on 4 replications. The main plots included irrigation treatments at three levels: I1- normal irrigation, I2- irrigation withdraw from the beginning of the flowering stage to the end of the growth period, and I3- irrigation withdraw from the beginning of the grain filling stage to the end of the growth period and the sub-plots included foliar application treatments at four levels: S0 - foliar application of water, S1 - foliar application of zinc, S2 - foliar application of manganese and S3 - foliar application of zinc and manganese. Significant interaction between stress levels and foliar application showed that the number of spikes per plant in treatment where irrigation withdraw at flowering and irrigation withdraw at the grain filling stage was affected by both zinc and manganese foliar application treatments and increased with irrigation water compared to foliar application treatments. The number of grains per spike followed the same trend and no significant difference was found between treatments at different levels of stress and foliar application regarding 1000 grain weight. A significant interaction between stress and foliar application levels on grain yield and harvest index showed that wheat Sirvan cultivar behavior in two years of experiment is different from that of foliar application levels at each level of stress. In general, the results of the experiments revealed that the tolerance of wheat cultivar Sirvan under terminal drought stress conditions increased with zinc and manganese foliar application and had a high yield stability.