Role of Zinc on Drought Tolerance in Some Wheat (Triticum aestivum L.) Cultivars under Reduced Soil Water

Abstract

Received 09/11/2021; Accepted 10/1/2022 DOI : 10.21608/agro.2022.105221.1291 ©2021 National Information and Documentation Center (NIDOC) involved in many biochemical pathways (Alloway, 2009; Cakmak et al., 2017). The presence of some micronutrients needed for plant growth may alleviate the effect of dehydration. Interestingly Zn, B, and Mn applications raise the resistance of plants to drought stress (Khan et al., 2004; Movahhedy-Dehnavy et al., 2009). Otherwise, drought stress has exerted a negative effect on relative water content of leaves (RWC), and durum wheat under water stress loses much more water than the bread wheat. Larbi et al. (2004), Akram (2011) and Keyvan (2010) indicated that increase in the intensity of drought stress decreased RWC, total chlorophyll and increased proline content. Also, Tale & Haddad (2011) stated that drought stress closes stomata, inhibits photosynthesis and damages the chlorophyll contents. Furthermore, Almeselmani et al. (2012) recorded reduction in all physiological traits, yield and yield component in D is a serious abiotic stress affects crop production in Egypt and worldwide. Two experiments were carried out under drought stress and normal irrigation during the seasons of 2018/19 and 2019/20 to study the effect of foliar application of Zn to alleviate drought stress. The soil texture is clay. The genetic materials were three Egyptian cultivars; Sakha 69, Giza 68 and Gemmieza 11. The levels of foliar spray of zinc oxide were 500ppm, 250 ppm, water and control (no treatment), sprayed two weeks before and at anthesis. Mean squares of the combined data was significant (P≤ 0.01) for Zn levels and for yield traits except for spike length. The differences among cultivars were significant (P≤ 0.01) except for yield under irrigation. This confirms the concept of “selection for yield under stress is better than under favorable environment”. The traits plant height (PH), number of spikes/plant (NS/P), biological yield/plant (BY/P), grain yield/plant (GY/P) and 100GW showed the best performance at the higher Zn level 500ppm. Water deficit exerted negative effects on RWC% and chlorophyll. The reduction % (the difference between irrigation and drought stress relative to irrigation performance) in all traits was the lowest at 500ppm of Zn and increased ascendingly by decreasing the Zn level. Sakha 69 significantly showed the best performance for PH, NS/P and BY/P under both, drought stress and normal irrigation. It could be concluded that Zn foliar application alleviated drought stress, and Sakha 69 was the most stable cultivar in GY/P and gave the best performance under drought stress.