Interaction between fungi and plant growth-promoting Rhizobacteria and their role on red bean (Phaseolus vulgaris L.) cultivars

Introduction Nowadays, in conventional farming systems, due to the limited amount of cultivated land and the need for most of communities to increase the production of agricultural products, unbalanced fertilizers, especially nitrogen and phosphorus, have been consumed. The study of nitrogen (N), phosphorus (P2O5) and potassium (K2O) fertilizers use in 2014 indicates that the average total consumption of these fertilizers worldwide is 85.5, 2.3 and 20.4 (kg. ha-1), an increase of 31.7, 28.1 and 12% respectively compared to 2000. On the other hand, increasing the health and security of food products produced in agricultural systems is essential for maintaining the dynamism of ecosystem resources based on ecological principles. Unbalanced consumption and excessive demand for chemical inputs (fertilizers and pesticides) have caused instability in farmland systems and the irreparable economic and environmental consequences of their consumption in agriculture all over the world. Sustainable agriculture relies on the reduction or elimination of chemical inputs for agricultural production, with the aim of achieving long-term sustainable production and adaptation to the environment. The main objective of sustainable agriculture is to increase the efficiency of the internal cycle of soil nutrients and the use of organic and organic fertilizers as an alternative to chemical fertilizers in order to improve the stability of grain yield and quality, while maintaining the proper utilization of soil and water resources in agricultural ecosystems. Researchers have shown that more attention to soil management and the beneficial potential of microorganisms from plant to soil can enhance biodiversity, health and, consequently, the dynamics of soil elements. So, in order to achieve a sustainable agricultural system, it is necessary to use inputs that improve plant ecological aspects in addition to meeting plant needs and reduce the negative effects of chemical inputs.   Materials & Methods This experiment was conducted as factorial layout based on a randomized complete block design with four replications during growing season of 2016 at the experimental field of Beiranshahr city of Khorramabad in Lorestan Province, Iran (48° 31' E, 33° 40' N and 1653m above the sea level). Before conducting the experiment to determine the physical and chemical properties of soil samples were collected from 0-30 and 30-60 cm depth of soil. During this experiment effects of three factors were studied: 1. Inoculation with Arbuscular Mycorrhizal M (Glomus etunicatum, G. Intraradices, G. mossea) in tow levels (M1= inoculation, M2= no inoculation), 2. Inoculation with Azotobacter chroococcum (strain 15) A, in tow levels (A1= inoculation, A2= no inoculation) and 3. Different Cultivars of Red Bean (Phaseolus vulgaris L.) in three levels (V1: Beiranshahr landrace, V2: Akhtar and V3: Goli varieties). The seeds were inoculated with mentioned biological compounds before culturing. Traits such as: number of pods per plant, seeds per pod, number of seeds per plant, 100 seed weight, seed yield, biological yield and harvest index were measured.   Results & Discussion The results showed that the effect of Azotobacter and Mycorrhiza, number of pods per plant, 100 seed weight, harvest index in the red bean cultivars were significantly increased, and as well as the effect of the Mycorrhiza and cultivars, the number of seeds per pod, 100 seed weight, biological yield and harvest index Bean cultivars were significantly increased. Azotobacter and Mycorrhizal inoculation, 12.4 and 24.5 percent, respectively Bean plant yield was increased compared to control treatment. The highest grain yield in Goli varieties were compared to the 45.2 and 51.1 percent, Akhtar varieties and Beiranshhr landrace, respectively.   Conclusions Obtained results of this experiment showed that the yield and yield components of Red Bean cultivars were influenced by applied treatments.  It seems that the use of biological fertilizers (Mycorrhizal and Azotobacter) through better root and shoot growth, the balance between vegetative and reproductive development and improvement of bean pods per plant, seeds per pod, number of seeds per plant and 100 seed weight, could bean cultivars to significantly increase of economic performance. In this experiment, avoiding the use of chemical fertilizers, especially nitrogen and phosphorus was reduced traits significantly. That biological fertilizers cooperative could this decrease was caused by created nutritional, compensation. In general, the use of these microorganism’s favorable conditions for improving the yield and yield components of Bean plant provides. Generally, the application of these microorganisms provided the best conditions for improving the yield and yield components of bean plants, which, in view of the objectives of sustainable production of this plant, as well as to reduce the use of fertilizers in stable indigenous agricultural systems, could be used to be placed.