Response of some agronomic traits of some wheat genotypes to cut of terminal irrigation with zinc foliar application

In regions of Iran with Mediteranean climate, drought stress generally occurs in terminal wheat growth stages. Using tolerant varieties and some agronomic operations may decrease the damage of this stress. In order to study the reaction of 11 wheat genotypes to terminal drought stress under two zinc consumption conditions, the study conducted during 2011-2013 crop season at Isfahan. Genotypes were WS-82-9, Sirvan, WS-86-14, Pishtaz, Parsi, Back-cross-Roshan, Arg, Roshan, Pishgam, Alvand and Mahdavi were evaluated under three treatments, normal irrigation, no irrigation after heading and also no zinc application, and no irrigation after heading and two times foliar application of zinc at vegetative growth stages. Results showed that all studied traits except no. of spikes per m2 and days to anthesis decreased under terminal drought stress. Drought stress decreased grain yield of genotypes between 36.2-59%. Among the yield components, the most reduction occurred in thousand kernel weight. Grain yield increased by an average of 7.3% under zinc foliar application. But the reaction of genotypes varied between 5.2% to 9.8%. Zinc application caused significant increase in grain weight via improved grain filling rate, so thousand kernel weight and grain filling rate were 2.4 gr and 0.091 mg grain-1day-1 greater than no-zinc application. Varieties Pishgam and Sirvan can be recommended for cultivation in areas with probability of terminal drought strees.