The effect of planting date and symbiotic Mycorrhiza fungi on physiological and growth characteristics of three cultivars of potato

In order to investigate the effect of planting date and Mycorrhiza fungi on the physiological, growth characteristics and yield of three cultivars of potato tuber, the treatments were planting date as the main plot at three levels (May 15th, June 1st and June 15th) and the consisted of a factorial combination of three potato cultivars (Agria, Santhe and Arinda) and two levels with and without mycorrhiza as subplots. The results showed that the highest yield of potato tuber cultivars achieved with Arinda in the early cultivating date (May 15th) (38 t ha-1). It was determined that the planting date of May 20th due to the interaction of stages of plant growth (especially flowering) with the maximum temperature of the region was affected by environmental stresses that had a negative effect on the physiological characteristics associated with the photosynthetic pigments. As a result, decreased potato tuber yield in Fereydoun Shahr area. Mycorrhiza has a positive effect on root development, improves the pigments and increases the dry weight of the roots, leaves and shoots. It seems that Agria have less tolerance to environmental stresses due to less production of non-enzymatic (carotenoid) and enzymatic (catalase, peroxidase and ascorbate peroxidase) anti-oxidant, resulting in lower tuber yield in all three planting dates in presence or absence of mycorrhiza.