MICROBIAL POPULATION CHANGES IN THE RHIZOSPHERE OF TOMATO SOLANUM LYCOPERSICUM VARIETIES DURING EARLY GROWTH IN GREENHOUSE

Abstract

The microbial population changes in the rhizosphere of two varieties of tomato: cherry and plum were studied. They were grown in a greenhouse for five weeks. Standard microbiological procedures were applied. Biochemical and cultural characteristics revealed the presence of Bacillus, Enterococcus, Staphylococcus, Rhizobium as bacterial species and Penicillium, Mucor and Saccharomyces as fungal species. Total Heterotrophic Bacterial Counts (THBC) ranged from 1.0 x 106 to 4.8 x 107 cfu/g; 7.0 x 107 to 4.5 x 109 cfu/g and 5.4 x 107 to 3.0 x 109 cfu/g for bare soil, rhizosphere soil of cherry tomato and rhizosphere soil of plum tomato respectively. Total Fungal Counts (TFC) were lower and ranged from 1.3 x 106 to 6.5 x 106 cfu/g, 1.2 x 106 to 8.7 x 106 cfu/g and 1.0 x 106 to 1.2 x 106 cfu/g for bare soil, rhizosphere soil of cherry tomato and rhizosphere soil of plum tomato respectively. The microbial succession pattern further revealed that Bacillus sp, Enterococcus sp, Rhizobium sp, Mucor sp and Saccharomyces sp were the predominant microorganisms present in bare soil and rhizosphere soils of cherry and plum tomatoes. The presence of plant growth promoting rhizobacteria e.g. Bacillus sp and Rhizobium sp, is of great advantage to the early growth of tomato plants as they play important roles in increasing soil fertility, plant growth , and suppression of phytopathogens for healthy plant development and sustainable agriculture.