2.1. Biological material
The common bean genotypes were CocoT and Flamingo. The
first one was selected as a pure line from the local cultivar
Coco whereas Flamingo was selected on the basis of its tolerance
to salinity (Jebara et al., 2001) among a collection initially supplied by B. Voyesset from CIAT (Colombia). Seeds were
surface-sterilized with 1.3% calcium hypochloride for 15 min
with constant stirring, and subsequently washed with sterile
distilled water. They were germinated on 0.8% sterile agar
plates for 3 days at 28 C in the dark, with a germination rate
of 80%. Rhizobial inoculation was performed by soaking the
seedlings of common bean for 45 min within a freshly prepared
suspension of Rhizobium tropici CIAT899 containing 108 bacteria
ml1