Evaluation of inoculation methods for screening of germplasm against Dickeya Zeae inciting stalk rot of maize
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Date
2022-07
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G.B. Pant University of Agriculture and Technology, Pantnagar, District Udham Singh Nagar, Uttarakhand. PIN - 263145
Abstract
Bacterial stalk rot (BSR) of maize caused by Dickeya zeae is one of the devastating diseases of maize rop in India especially in tarai region of Uttarakhand. Present study were carried out for identification and characterization of test bacterium, evaluation of different inoculation methods to artificially create disease under field and glasshouse conditions and to find out best susceptible for disease screening programme. The bacterium was found to be gram negative, oxidase negative, KOH positive, catalase positive and latin liquification positive. Bacterium produced red colonies on Logan’s media, deep pit on CVP media and blue pigment on NGM media. These tests along with molecular identification indicated that the isolated bacterium was Dickeya zeae. Under glasshouse conditions 4 genotypes CM 600, PSM 6, Chakrata Local, and Rasi 4212 were inoculated with 4 different inoculation methods. Maximum disease incidence and severity (PDI) was observed in syringe inoculation followed by tooth method. Highest disease incidence and severity was found in Chakrata Local followed by CM600 while lowest in PSM 6. In germplasm screening 10 different genotype such as ADV 7022, IIMR PBT POOL, RCRMH 41, CM 500, CM 600, PSM 6, Early Composite, Surya, Chakrata Local, and Rasi 4212 of maize were evaluated by syringe inoculation. PSM 6 showed lowest disease incidence and severity while maximum incidence and severity found in Chakrata Local. Under field trail different inoculation methods were evaluated over 2 genotypes - PSM 3 and DKC 9106. Highest disease incidence and severity was found in stem injection followed by tooth-pick. Based on above findings syringe inoculation method was found to be best inoculation method for artificially creating BSR of maize and Chakrata Local found as most susceptible genotype.