Niger seed (Guizotia abyssinica Cass.) is a multipurpose plant that has imported to Iran as a bird seed and doesn't have any scientific report in Iran. In order to evaluate the agronomic and physiological characters of Niger seed (as an oil seed and medicinal plant) in different seasons and sowing dates, some acts such as authentication of this species was done. Niger seed has been sown in autumn, spring and summer. Also in summer the effect of sowing date in a completely randomized design with 4 replications and 3 treatments (9 June, 21 June and 3 July) was evaluated in Isfahan province in 2010. According to the results, autumn and spring were not suitable season of cultivation of this plant and it can be grown in summer successfully. The effect of various summer sowing date, on most of the measured traits were significant. The best planting date was about the third planting date in Isfahan climatic conditions. The highest value of the number of capitula per plant (59.07), 1000 seed weight (3.39), seed yield per hectare (874.7 kg), number of seeds per plant (1510), seed oil (47.33) were obtained from the third sowing date. While the highest plant height (150.1cm), days to 50% flowering (67), days to 80% maturity (110) was recorded from the first sowing date.

In order to investigate the effects of mycorrhizal fungi on yield and water use efficiency of eight sesame (Sesamum indicum L.) genotypes in different levels of drought stress, an experiment was conducted using a factorial split plot with three replications in the research field of the Urmia agricultural high school in 2014. The main factor was consisted of different levels of irrigation as: normal irrigation (irrigation after 70 mm evaporation of the crop (ETc), moderate drought stress (irrigation after 90 mm ETc) and severe drought stress (irrigation after 110 mm ETc), and two species of mycorrhiza fungi (Glomus mosseae, Glomus intraradices) and non-inoculated (control). 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. Results showed that the effect of irrigation, mycorrhiza fungi and genotypes on studying traits was significant. Mean comparisons showed that with increasing severity of drought stress, grain yield, biological yield, water use economic and biotic efficiencies decreased significantly. Severe drought stress reduced water use economic and biotic efficiencies about 62 and 49 percent, respectively. Using two species of mycorrhizal fungi (Glomus mosseae, Glomus intraradices) in comparison with non-inoculated (control) had significant effect on all studied traits. Inoculation with G. mosseae improved seed yield, biological yield and water use economic efficiency compared to control with 33, 42 and 33 percent, respectively. Moghan landrace and Zanjan Tarom landrace based on yield and water use efficiency, had superiority on other landraces. Mycorrhiza led to improve yield of landraces and in severe drought stress conditions, sesame plants showed a higher mycorrhizal dependency.