Impact of foliar application of growth hormones at stages of yield components formation of two wheat cultivars under dry-land conditions

In order to investigate the effect of exogenous application of different growth regulators (IAA, GA3and 6-BAP) and distilled water (control) at different stages of spike growth and development (double ridge, booting, grain filling and booting grain filling) of two wheat cultivars spike (Rijaw and Azar-2), a biennial experiment as factorial based on randomized complete blocks design with three replications under dry-land conditions was conducted at the research field of Campus of Agriculture and Natural Resources of Razi University. The results of the experiment showed that each of yield component under the effect of certain hormone and timing of hormone consumption treatments changed. As the influence of 6-BAP and IAA at booting early of grain filling and booting stages , respectively, had the highest number of seeds and 6-BAP hormone in the initial stage of the grain filling had the greatest impact during grain filling on one-thousand grain weight with the averages of 41.8 and 37.4 gram in both years of the experiment. The highest final grain yield was obtained by application of 6-BAP and GA3and at booting early stage of grain filling. There was a high and positive correlation between the grain number and grain yield. The obtained results of bi plot analysis showed that the grain number trait could have different response to the type of used hormone in different years but this reaction was constant for the growth stage and cultivar and also, the changes in one-thousand grain weight and number of grain per spike for the best selected treatment combination have less reactivity than the other traits.