Effect of different strains of rhizobia on the growth and yield of two cultivars of common bean

A field study was conducted at Karaj Soil and Water Research Station to evaluate the effects of bean nodulating rhizobia on the growth and yield of two bean cultivars. The experiment was carried out using two cultivars of bean, Faculty white and Naz red as well as four strains of rhizobia, one nitrogen (100 kg N/ha) as urea and a control treatment in a randomized complete block (RCBD) split plot design in four replicates. The strains were grown in YMB to obtian population density of 2108 cfu/ml and then packed following the injection to 25 g of powdered perlite. Seeds of bean were moistened with a 20% solution of Arabic gum and treated with the inocula before planting. N-fertilizer as urea was used in three equal applications at planting, flowering and pod filling. Control treatment included no inoculation or N- fertilization. Plants were sampled at flowering and physiological maturing stages. The leaf area, plant height, nodule dry weight and N-uptake of the shoots were measured at the first sampling time. With the second sampling, number and weight of the pods per plant, number of the seed per plant, 100-seeds weight, biological yield and protein content of the seeds were measured. Results showed that the inoculation increased is significant in the noduledry weight, leaf area, plant height, N- uptake of the Shoots, number and weight of poods per plant, number of the seed per plant, biologic yield, seed yield and protein content of the seeds than Control and one nitrogen (100 kgN/ha), and so L-100 strong of rhizobia has most seed yield. The cultivars had significant differences and the cultivar Naz red was superior in the measured indices.