The Effect of Application of Plant Growth Regulators on Yield and Yield Components of Two Bread Wheat Cultivars under Different Irrigation Regimes

In order to study the effect of cytokinin, gibberellin, and cycocle on yield and yield components of two wheat cultivars under different irrigation regimes, a study was conducted as a split-split experiment based on a randomized complete block design with three replications at the Agricultural Research Station of Kurdistan University in 2016. There, the irrigation factor at four levels: dryland, irrigation at booting stage, irrigation at booting + flowering and irrigation at booting + flowering + grain filling stages have served as the main plots, two wheat cultivars (Sirvan and Homa) as sub-plots, and levels of plant growth regulators foliar application including, i.e. control, gibberellin (100 µm), cytokinin (100 µm), and cycocel (3gr. lit-1) at the wheat stem elongation and grain filling stages as the sub-sub plots. Results show that in the foliar application during the stem stage, compared to the dryland treatment, yield increase in one, two, and three irrigation treatments have been 29%, 33%, and 43%, and at the grain filling stage; 22%, 28%, and 33%, respectively. Homa cultivar produced higher yield compared to Sirvan. In the foliar application during the stem stage, the highest grain yield (504 g m-2) belongs to application of three irrigation treatments as well as addition of cytokinin, and at the grain filling stage, the highest grain yield (477.6 g m-2) has been obtained from Homa cultivar under three times irrigation condition and cycocel consumption. Therefore, using even one stage irrigation and the application of cytokinin and cycocel can increase the grain yield of wheat.