A Preliminary Evaluation of Symbiotic N Fixation in Mungbean


  •  Charles Salley    
  •  Harbans L. Bhardwaj    

Abstract

We are interested in developing mungbean [(Vigna radiata (L.) R. Wilczek] as a short duration summer crop to be produced in rotation with winter wheat due to its’ increasing popularity and potential for Symbiotic N Fixation (SNF). However, scarcity of mungbean SNF information is limiting to support its use as an N-fixing crop. We conducted a greenhouse study with ten mungbean genotypes and twelve Bradyrhizobium strains. The objective was to study nodule traits (number and size) and chlorophyll concentration in leaves using Minolta SPAD meter using a CRD design with six replications. Eight to ten seeds of each of the 120 combinations were planted in vermiculite and inoculated with the bacterial strains. Upon germination, plants were thinned to six plants per pot. The data were recorded on approximately 40-day old plants. Results indicated that variation for nodule traits was not significant. However, significant effects of bradyrhizobial strains and mungbean genotypes on SPAD readings were observed. Results indicated existence of specificity between mungbean genotypes and bradyrhizobial strains, as indicated by significant interaction for SPAD values. We identified three bradyrhizobial strains (Strain-11 isolated from partridge pea, Strain-12 isolated from Baptisia sp., and Strain-3-CB 756, wide range type strain from Australia) to be highly efficient. Three mungbean genotypes (MB-80, TexSprout, and MB-84) were identified to be best for SNF. The results provide basic information to support future detailed SNF research in mungbean.



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