Leaf area index (LAI) and radiation use efficiency (RUE) are important ecophysiological characteristics for the realization of crop growth, development, and radiation absorption. A factorial field experiment was carried out base on a randomized complete block design with three replications. Two mung bean genotypes (Dezfouli and Indian) were planted under six fertilization treatments during 2017 and 2018. Six fertilization treatments include: 1- free-living nitrogen fixating bacteria (NFB), 2- phosphorus solubilizing bacteria (PSB), 3- potassium solubilizing bacteria (KSB), 4- free-living nitrogen fixating bacteria + phosphorus solubilizing bacteria + potassium solubilizing bacteria (NFB+PSB+KSB), 5- nitrogen fertilizer (source of urea 46%) and 6- Control (without biological and chemical fertilizers). The maximum LAI was recorded in NFB+PSB+KSB treatment in Dezfouli genotype that compared with controls, increased by 37, and 42% respectively in 2017 and 2018. The maximum absorbed radiation at NFB+PSB+KSB treatment increased by 20, and 12% compared to the control in 2017 and 2018. Also, maximum radiation was proportional to the time of maximum LAI. During 2017 and 2018, the highest Radiation use efficiency (1.21 and 1.03 g MJ-1 m-2, respectively) obtained from Indian genotype in the NFB+PSB+KSB application. The greatest effects of plant growth-promoting rhizobacteria (PGPR) was observed in the NFB+PSB+KSB treatment compared to other treatments. The PGPR could promote mung bean biomass via increasing of LAI and radiation use efficiency.

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