SCREENING OF PGPR ISOLATES FROM SEMI-ARID REGION AND THEIR IMPLICATION TO ALLEVIATE DROUGHT STRESS

During the present study isolation of 24 plant growth promoting rhizobacteria isolates were made from rhizosphere soil of maize collected from semi-arid region of Kahuta, Pakistan having 12% soil moisture. These isolates varied considerably on the basis of colony morphology, Gram's test and catalase test. Most efficient bacterial isolates were screened on the basis of their positive activity for siderophore production, P-solubilization and bacteriocin production. The PGPR isolate 9K showed maximum P-solubilization index. Siderophore production was exhibited by 1K (1Kahuta) and KB (KahutaB) while (KahutaB) showed bacteriocin production also. The PGPR isolates1K, KB and 9K were selected for re-inoculation studies on maize under induced drought stress condition. The PGPR isolate 9K increased drought tolerance in maize plants by enhancing root proliferation and improving relative water content of leaves, significant (26%) increased in root to shoot dry weight ratio as compared to inoculated control. The PGPR isolate 9K can be selected in the formulation of bio-fertilizers for alleviating drought effects in arid and semi-arid region.