ESPECIFICIDADE SIMBIÓTICA ENTRE RIZÓBIOS E ACESSOS DE FEIJÃO-CAUPI DE DIFERENTES NACIONALIDADES

Abstract

This work aimed to evaluate nodular occupancy rate of rhizobium strains inoculated in different cowpea accesses (Vigna unguiculata (L.) Walp) from Brazil, USA and Nigeria and their relationship with the symbiotic specificity. The identification of strains in nodules was done using Enzyme-Linked ImmunoSorbent Assay (Indirect-ELISA). It was observed that the nodule number and weight were influenced by the origin of cowpea accesses. The inoculation was able to promote a significant increase in the number of nodules occupied by serogroup of inoculant strain. In agreement with the cowpea accesses origin, the Brazilian accesses presented the largest of nodule occupancy rates, followed by those of Nigeria and USA. The largest occupation percentage, in 6 of the 10 tested cowpea, was due to the innoculation with the BR 3273 strain, and the smallest one was due to BR 3269 strains, in 8 of the 10 cowpea accesses. These data suggests that specificity exists between rhizobium inoculant strains and cowpea accesses.