Investigating the effect of water stress and plant density on some physiological characteristics and water use efficiency in two ecotypes of Thymbra spicata L.

In order to investigate the effect application of mycorrhizal fungus and potassium fertilizer on trait of Black Cumin (Nigella sativa) in different irrigation levels, an experiment was conducted as split factorial based on randomized complete block design (RCBD) with 3 replications during 2018-2019 in Marvdasht city. Four irrigation levels with 100, 75, 50 and 25% of field capacity were considered as the main plot and application and non-application of mycorrhizal fungus, application and non-application of potassium fertilizer as a factorial in the sub-plot. Analysis of variance indicated that the effects of irrigation, mycorrhiza, potassium, and also the interaction between irrigation and mycorrhiza on the studied traits were significant. With increasing of drought stress, plant height, number of lateral branches, number of follicles per plant, grain yield, biological yield and oil yield was decreased. The highest grain yield related to irrigation 100% of field capacity in the application of mycorrhizal (856 kg/ha) and the lowest grain yield was obtained irrigation with 25% field capacity in non-application mycorrhizal (174 kg/ha). Also, the results indicated that the application of mycorrhizal in treatment irrigation with 75% of field capacity led to an increase in traits of Black Cumin and there was no significant difference with 100% field capacity irrigation and no application of mycorrhizal treatment. In the 25% field capacity of irrigation, no significant difference was observed between the application and non-application of mycorrhizal for most traits of Black Cumin.