عنوان مقاله [English]
Background and objectives: Drought is one of the most important factors limiting crop production and one of the main problems in many parts of the world. Sesame is one of the oilseeds due to the high content oil (52-47%) and high quality (low in cholesterol and some anti-oxidants), an important role in human health. The use of bio-fertilizers to reduce the use of chemical fertilizers and increasing yield, are an important issue in order to move towards sustainable agriculture. Arbuscular mycorrhizal fungi are one of the main components of bio-fertilizers and main part of the flora of plant roots in natural ecosystems. One of the mechanisms that enhance the stability of plants to drought stress use of symbiotic relationship of mycorrhiza is. There is still limited information about the sesame plant symbiosis with fungi in drought stress conditions. Therefore, this study was conducted to identify sesame tolerant landraces to drought stress using productivity effort, quantity and quality yield in presence or absence of different species of mycorrhizal in Urmia.
Materials and methods: This study was done using factorial split plot design with three replications in research field of Urmia agricultural high school that is located in the 12 km road Urmia - Mahabad. Longitude of site is 45 degrees and 2 minutes, and latitude 37 degrees 32 minutes and the average height of 1332 meters above sea level. The main factor was consisted different levels of irrigation, normal irrigation (irrigation after 70 mm evaporation of crop (ETc)), moderate drought stress (irrigation after 90 mm ETc) and severe drought stress (irrigation after 110 mm ETc), sub plots including two kinds of mycorrhizal fungi Glomus mosseae, Glomus intraradices (10 grams of fungi treatments are thrown in per hole then the fungi covered with soil as much as two centimeters with soil, then seeds were sown on the soil and then the seeds were covered with soil about three cm) and non-inoculated (control). Sub-sub plots consisted of eight landraces of sesame names Jiroft13, Zanjan Tarom landrace, Moghan landrace, several branches Naz, TC-25, TS-3, Darab 14 and Dashtestan 5. Traits of studied in this research were grain yield, grain yield per plant, biological yield, total dry weight per plant, harvest index, productivity effort, the oil yield and chlorophyll.
Results: According to the results, the effect of drought stress and mycorrhiza on all traits except harvest index and productivity effort was significant. Interaction of irrigation and genotypes on all traits except for productivity effort was significant. Interaction of mycorrhizal and genotypes only on biological yield and plant dry weight were significant. Landraces studied in different levels of drought stress and mycorrhiza had different reactions.
Conclusion: Mean comparison showed that with intensity of drought stress, all traits were significantly reduced. Severe drought stress reduced grain yield and biological yield about 63 and 52 percent, respectively. Use of two species of mycorrhizal fungi in comparison with control (lack of mycorrhiza) increased all traits. The landraces of sesame examined in this study, landraces Moghan and Zanjan Tarom for studied traits were superior to other landraces. According to the results, to improve grain yield of sesame landraces using mycorrhizal fungi especially species G. mosseae was recommended.