Improving sesame (Sesamum indicum L.) seed characteristics and vigor under drought stress by seed zinc and boron enrichment

Drought stress on maternal plant can negatively affect germination characteristics of produced seeds, and micronutrients application in this circumstance may mitigate drought impacts and leads to seeds with higher vigor. This research was conducted as two experiments in 2015 in seed laboratory of Yasouj University. At first experiment the seeds obtained from a former experiment included of three irrigation levels (after 75, 110 and 145 mm evaporation from class A pan) and four foliar applications included of water, zinc sulfate 3000 ppm, boric acid 2000 ppm and mixture of zinc sulfate and boric acid, were evaluated in germination experiments in 30°c. Second experiment was a factorial based on RCD with three replications. First factor was drought stress, by PEG 6000, in three levels (0, -0.2 and -0.4 Mpa), and second factor in eight levels included of seed soaking in water, ZnSo4, H3Bo3 and ZnSo4 + H3Bo3 and seed with high content of Zn , B and Zn+ B and a dry seed as control. First experiment results showed that with delaying in irrigation time, foliar application of micronutrients, compared to water foliar application, significantly increased germination traits. In second experiment, although seed soaking in nutrients, significantly decreased germination indices, but seed with high zinc and boron contents positively affected on germination vigor and antioxidant activities especially under drought stress condition.