بررسي اثر تنش آبي بر روي تبخير تعرق و شاخص هاي توليد گياه گندم زمستانه

Investigation of the effect of water stress on ET and yield criteria of winter wheat

To investigate the effect of water stress on ET and yield criteria of winter wheat, an experiment was conducted in Mashhad region. A complete randomized block design with 9 treatments and 3 replications were used. The first treatment (control treatment) was irrigated in all growth stages of the plant, six treatment were irrigated on the basis of no watering in a specific growth stage (germination, tillering, jointing, flowering, seeding and ripening) and the two remaining treatments were irrigated on the basis of 20 and 60 percentages of their potential water needs. The amounts of actual evapotranspirations were determined in different experimental treatments by using the water balance equation. The results showed that water stress caused plant could not reach their potential evapotranspirations after the end of stress period. In addition to that, water stress caused the reduction in the amount of plant coefficient and leaf area index. the results show that there is significant difference in the amount of seed yield, harvest index, water use efficiency and the component of yield between control treatment and other treatments (p<0.05). As well water stress affected yield mainly via reduction in the weight of 1000 seeds and the number of seed in spike more than the number of spike per area unit.