Three strains of plant growth promoting fluorescent Pseudomonads (HPR6, RRLJ008 and RRLJ134) were studied
for their effect on growth and yield of French bean (Phaseolus vulgaris L.) under field conditions. The effect of
these strains on nature of root development and leaf palisade tube length were also examined. The strains induced
positive response on growth and physiological parameters resulting in higher yield in P. vulgaris. Strain HPR6
produced the most promising results in thickening of leaf palisade layer, spreading of lateral roots and production
of root hairs. The increase in specific leaf weight (SLW), net assimilation rate (NAR) and relative growth rate
(RGR) by these strains were 68%, 152% and 167%, respectively. The growth and yield parameters were also
significantly improved compared to the uninoculated control. Antibiotic resistant mutant strains demonstrated that
these bacteria effectively colonized the rhizosphere of French bean. The results suggest that the strains could be
developed for field application on a large scale
