COMBINED EFFECT OF DIFFERENT POTATO ASSOCIATED Pseudomonas STRAINS FOR IMPROVED BIO CONTROL OF Rhizoctonia solani

Potato (Solanum tuberosum L.) is a cash crop belonging to family Solanaceae having dicotyledonous and genetically diverse crop. There are about 90 genera and 2,800 known species of potato across the world. Potato is cultivated in 149 countries with annual production is about 72 million tons. Number of pathogens like fungi, bacteria, viruses and nematodes are responsible for causing more than 40 different diseases in potato crop. Rhizoctonia solani (Thanatephorus cucumeris) has a wide range of host. The fungus isolates are separated into subgroups which are closely related but genetically different R. solani known strains have 13 anastomose groups and the most notable anastomose classes are AG-4, AG-3 and AG-2. Anastomose class 3 (AG-3) is responsible for the development of sclerotia on potato tubers. Pseudomonas is known of having fast-growing character and used as a biological control of R. solani. Different antimicrobial compounds are produced by Pseudomonas like phenazine-1-carboxylic acid (PCA), pyoluteorin (Plt), hydrogen cyanide (HCN) and pyrrolnitrin (Prn).Maximum inhibitory efficiency was observed by Pseudomonas strains IUB310 (98.4%) while the KAR1220 (59.2%) showed minimum control efficiency against R. solani. Completely randomized design CRD was used in lab. For comparing the differences between the means least significant difference test (LSD) was used at the 5% variation. In vivo experiments biocontrol adequacy and percent yield increment by different bacterial antagonists were assessed. Measurable examination showed that both Pseudomonas strains IUB310 and Ck2020 were the best with 78.64 and 76.16 percent biocontrol adequacy, just as 59.12 and 54.32 percent yield increment, separately. The ultimate aim of present research is to replace synthetic chemicals by using Pseudomonas strains to control R. solani that cause sclerotic in potato.