EFFECT OF ENDOPHYTIC BACTERIA ON THE RHIZOSPHERE MICROFLORA OF MULBERRY (MORUSALBA L.) INOCULATED WITH ROOT ROT PATHOGEN RHIZOCTONIA BATATICOLA (TAUB.) BUTLER.

摘要

Mulberry (Morus alba L.) the only food plant for silkworm (Bombyx mori L.) is grown in 200 000 ha. Under different agro-climatic conditions. In recent past root rot disease caused by Rhizoctonia bataticola has become one of the major threat to mulberry cultivation in all mulberry growing areas. For the suppression of the disease talc based bioforniulations of rifampicin resistant endophytic bacteria viz., Burkholderia cepadcia, Bacillus subtilis and Pseudomonas aeruginosa were developed. The persistence of endophytic bacteria inside the root system and its effect on rhizosplane and rhizosphere microflora has been evaluated in glass house conditions under challenge inoculation method in pot culture experiments. Talc based bioformulations of endophytic bacteria and R.bataticola multiplied on sorghum seed were inoculated simultaneously to potting soil @ 0.4 % and 6.2 % w/w of soil respectively and filled in earthen pots. V-l variety mulberry saplings @ 2/pot were planted in inoculated pots. Persistence of endophytic bacteria in root system was evaluated at monthly intervals and rhizoplane and rhizosphere microflora after nine months. The rhizoplane and rhizosphere soil was dominated by Aspergillus species in all treatments and the pathogen R.bataticola was completely suppressed, whereas in pathogen control and absolute control pots the pathogen was recorded at a frequency of 47.4 % and 8.3% respectively on the rhizoplane. The root endophytic bacteria were isolated on rifampicin @ 100 pg / ml amendedLB agar and confirmed the persistence of bacteria in root system for long period and also its effect on control / suppression, of disease.