Inoculation with Trichoderma virens and Piriformospora indica for Improving the Morphological and Physiological Traits Related to Grain Yield of Rice under Different Rates of Phosphorus Fertilizer

Environmental protection and safity of agricultural products are two major goals in sustainable agriculture. Hence, using plant growth promoting rhizobacteria may be effective to reduce chemical inputs. Therefore, a field split plot experiment based on a randomized complete block design (RCBD) was conducted at Ghaemshahr, Mazandaran Province in 2015. Treatments were consisted of three levels of phosphorus (P) fertilizer (0 or control, 50 and 100 kg.ha-1 as triple super phosphate) and coinoculation of rice seed and seedling with Trichoderma virens and Piriformospora indica fungi with four levels (uninoculated control, inoculation of seed or seedlings and seed seedlings inoculation). Results indicated that inoculation with these fungi significantly and positively affected the morpho-physiological traits and paddy yield of rice plant in all P levels. When, 0, 50 and 100 kg.ha-1 was applied, seed inoculation resulted in significant increase of panicle number per plant (33, 19 and 40 percent, respectively), filled seeds per plant (21, 45 and 58 percent, respectively), biological yield (31, 6 and 18 percent, respectively) and paddy yield (37, 48 and 43 percent, respectively). Also, fungi inoculation of rice seeds, seedlings and seeds seedlings improved paddy yield up to 48, 53 and 53 percent and 43, 44 and 15 percent when 50 and 100 kg.ha-1 of P was applied, respectively. In general, results indicated that all three methods of fungi inoculation had positive effect on rice plants under all P levels, which could be related to those fungi ability to improving the parameters under study such as panicle number per plant and biological yield. In conclusion, the positive effects of using both microorganisms and P were more pronounced than using P alone.