Unclenching the potentials of global core germplasm for root nodulation traits for increased biological nitrogen fixation and productivity in chickpea (Cicer arietinum L.)

Chickpea being an important food legume crop is able to fix the atmospheric nitrogen and form root nodules that support biological nitrogen fixation- a sustainable alternative for nitrogen supply to agriculture worldwide. In order to support findings on nodule formation in chickpeas, a diverse core set of 300 chickpea genotypes, including four checks, was evaluated for morphological and nodulation traits in four different environments. The maximum genotypic and phenotypic coefficient of variation was observed for a number of nodules, nodule fresh weight, shoot fresh weight, and number of seeds per plant. The heritability for most of the characters ranged from 26.56 for days to 50% flowering to 99.61 for a number of pods per plant. The genotypic and phenotypic correlation coefficient analysis revealed that the number of nodules was positively correlated with seed yield. Further, seed yield was partitioned into direct and indirect effects at genotypic and phenotypic levels through path coefficient analysis. Significant genotypic correlations and direct positive effects were exhibited by a number of nodules and number of pods per plant on grain yield. Based on the D2 statistics, the number of seeds per plant, number of pods per plant, shoot fresh weight and number of nodules have been identified as top-ranking yield contributing traits. The genotypes ICC1013 and ICC16569 for a number of nodules and ICC1049 for the trait number of seeds per plant were identified as potential stable donors for the respective traits with high mean yield, heritability and genetic advance across the locations and can be used as donors in the chickpea breeding programs for increasing biological nitrogen fixation and enhancement of the crop productivity.