Yield and yield components of four maize hybrids with different stomata resistance in response to drought stress

This study was conducted in order to evaluation of stomata resistance response, transpiration volume for canopy temperature regulation and leaf rolling under drought stress condition for some new hybrids of maize. The experiment was laid out as a factorial design based on randomized complete block with three replications in 2015 and 2016 at Seed and Plant Improvement Institute, Karaj. Three Irrigation levels, include Irrigation after 60, 90 and120 mm cumulative evaporation from evaporation pan class A and four hybrids include KSC 703, KSC704, KSC705 and KSC706 were considered as the factors. The lower stomata resistance and canopy temperature were obtained in KSC 706 and caused not to have any leaf rolling in vegetative stage even under heat condition at noon, on the other hand grain weight was lower in KSC 706 in comparisons to other hybrids under mid and severe drought stress. The maximum and minimum of grain yield were obtained under normal irrigation and severe drought stress condition with average 7.64 and 3.34 ton/he respectively. Difference of grain yield in the hybrids were not significant but the most grain moisture was obtained from KSC 706 with average 17.61%. On the base of this experiment, KSC 706 due to opening the stomata and wasting moisture in environment around root zone via transpiration, may be sensitive to drought stress and it is not recommend for the areas where have limitation in irrigation water, although it can be recommended for tolerate to heat stress under optimum water irrigation condition.