Influence of Pseudomonas corrugata inoculation on root colonization and growth promotion of two important hill crops

Two isolates of Pseudomonas corrngata, P. corrugata 1 (a rhizosphere associ ate from subtropical region) and P. corrugata 7 (a rhizoplane associate fro m temperate region) were tested for their ability to improve growth and yie ld in two target plants. Amaranthus paniculatus and Eleusine coracana, grow n at the higher altitudes, were taken as test crops. Azotobacter chroococcu m, an established inoculant, was also used for comparison. The bacterial in oculations influenced plant growth and the nitrogen content of various plan t parts. Though the root colonization was also found to be stimulated, the majority of non-fluorescent pseudomonads isolated from the stimulated rhizo sphere or rhizoplane did not resemble the antibiotic resistance pattern of the inoculated bacteria. This indicated that the plant growth promotion due to introduced bacteria was largely due to stimulation of native microbial communities of the rhizosphere/rhizoplane region. Besides plant-microbe com patibility, the original habitat of the bacterial isolates was also found t o be important for the establishment and subsequent influence on plant grow th.