Effect of mycorrhiza application on plant growth and yield in potato production under field conditions

The effect of mycorrhiza fungi was studied on growth and yield of potato (Solanum tuberosum L.) in Fereidoonshahr, Esfahan, Iran during 2013 growing season. The experiment treatments were arranged in a factorial design based on a complete randomized block design with three replications. Four phosphorus fertilizer levels of 25%, 50% 75% and 100% P recommended with two levels of Mycorrhiza: with and without Mycorrhiza (control) were assigned in a factorial combination. Results showed that tuber size, number of tuber per plant, tuber yield, and starch yield were significantly higher in inoculated plants than in non-inoculated plants. Tuber size, number of tuber per plant, tuber weight per plant, number of tuber in m2, tuber yield, and starch yield increased with increasing P level above 75% P recommended in non-inoculated plants, whereas no significant difference was observed between 75% and 100% P recommended. The positive effect of mycorrhizal inoculation decreased with increasing P levels due to decreased percentage of root colonization at higher P levels. According to the results of this experiment, application of mycorrhiza in the presence of 50% P recommended had a favorable result and could increase tuber yield and starch production to an acceptable level. Therefore, mycorrhiza could be considered as a suitable substitute for chemical phosphorus fertilizer in organic agricultural systems.