Response of Tuber Yield and Some Physiological Growth Indices of Potato to Phosphate and Mycorrhizae under Moisture Stress

In order to study the effect of mycorrhizae and phosphate fertilizer on some physiological indices of growth and tuber yield of potato under moisture stress conditions, a field experiment was conducted in spring and summer of 2018 in Hamedan, west of Iran. This research was done as a factorial with three factors in a randomized complete block design with three replications. The first factor was moisture stress at three levels of irrigation after 60 (control), 80 and 100 mm evaporation from class A evaporation pan, the second factor was mycorrhizae (Glomus mossea) at two levels of application and non-application and the third factor was phosphate fertilizer at two levels of application and non-application. The results showed that in the absence of moisture stress, the maximum leaf area index decreased by 10.5% with use of mycorrhizae, but in moderate and severe moisture stress, the use of mycorrhizae increased it by 12.3% and 18.8%, respectively. Under severe moisture stress, mycorrhizae increased net assimilation rate and crop growth rate by 43.6% and 76%, respectively. At all three levels of moisture stress, the presence of mycorrhizae increased phosphorus agronomic efficiency. The presence of mycorrhizae in no-moisture stress had no effect on tuber yield, but at moderate and severe moisture stress, mycorrhizae improved it by 16.4% and 34.7%, respectively. In severe moisture stress condition, the application of phosphate increased tuber yield by only 15.8% compared to non-application of phosphate. Therefore, for potato production in conditions of moisture stress, the use of mycorrhizae with phosphate fertilizer is suitable.