| Iran is located in arid and semi-arid areas and has limited water resources that yield reduction due to low irrigation in these areas can be inhibited by programming and wise facilities usage. Supplemental irrigation is an approach that can lead to satisfactory and sustainable yield in dryland. The effects of supplemental irrigation on growth and yield of rainfed wheat (Var. Azar2) were investigated in at Dryland Research Station of Shirvan, during growing season of 2008-2009. Four sensitive stages of wheat to drought stress are A) germination, B) tillering, C) flowering, and D) seed set. Single or combined irrigation patterns in these four stages created 16 combinations. That it carried out based on randomized complete block design with 4 replications. These treatments included single irrigation in each stage (A, B, C, and D), two times irrigation (AB, AC, AD, BC, BD and CD), three times irrigation (ABC, ACD, ABD and BCD), four times irrigation (ABCD) and control (No irrigation). The results showed that supplemental irrigation had no significant effect on plant height, but its effect was significant on spike length, tillers and fertile tillers number, seed number per spike, 1000-seed weight, grain yield, harvest index and dry weight of wheat. The highest yield was obtained from 2 times irrigation in flowering and seed set stages (CD with 2009.2 kg/ha) which had no significant difference with 2 times irrigation in tillering and flowering stages. The lowest yield was obtained from no irrigation treatment (NO with 1045.2 kg/ha). The highest seed number per spike was obtained from BC and highest 1000-seed weight from AD. According to the result of this study, it could be concluded that supplemental irrigation in dryland wheat had significant effect on yield and can increase dryland wheat yield. So, it seems that enough water in flowering stage can increase the yield to a satisfactory level. |
