The introduced strain Mesorhizobium ciceri USDA 3378 is more competitive than an indigenous strain in nodulation of chickpea in newly introduced areas of China.

The present study aimed to compare the competitive advantage of two chickpea nodulating rhizobia strains (an indigenous strain Mesorhizobium muleiense CCBAU 83963 and an introduced strain Mesorhizobium ciceri USDA 3378) in different soils originated from new chickpea cultivation areas of China. The results showed that USDA 3378 had a significant competitive advantage in nodulation, with nodulation occupation rates ranging from 84·6% to 100% in all the sampled soils. According to the efficiency of symbiosis under single inoculation, chickpea plants inoculated with USDA 3378 showed better symbiotic performance based on the plant dry weight, leaf chlorophyll content and nodule numbers. The chickpea plants inoculated with USDA 3378 formed nodules about 2 days earlier than those inoculated with CCBAU 83963 . The higher growth in media and the stronger adsorption on chickpea roots of USDA 3378 when mixed with CCBAU 83963 may explain why USDA 3378 shows a competitive advantage. The results from this study will contribute towards the development of effective chickpea rhizobial inoculants for soil conditioning and more environmentally friendly production of chickpeas in China.