Evaluation of Inoculation Methods and Standardization of Erwinia chrysanthemi Inoculum Concentration for Germplasm Screening against Stalk Rot in Sorghum

Prachi Singh* and Yogendra Singh

Department of Plant Pathology, College of Agriculture, G. B. Pant University of Agriculture and Technology, Pantnagar – 263 145, U.S. Nagar, Uttarakhand, India.

Received on 11 May 2016 and accepted on 28 July 2016

 

ABSTRACT

Stalk rot caused by Erwinia chrysanthemi (Ech) is one of the most destructive diseases of sorghum crop. The bacterium was isolated from infected sorghum plants collected from livestock research centre, G.B. Pant University of Agriculture and Technology, Pantnagar, India. Evaluation of inoculation methods viz. leaf whorl inoculation, stem injection method, root tip cut dip method and tooth pick method was done in glasshouse by inoculation from 24 h old culture of Ech adjusted to 1×106 cfu/ml, 1×107 cfu/ml and 1×108 cfu/ml by adding sterilized distilled water and 0.7% (v/v) of tween-40 (surfactant). Leaf whorl inoculation, stem injection and root tip cut and dip method which showed significant results in glass house were further used for field experimentation. Root tip cut and dip method was observed to be the best inoculation method both in glasshouse and field experimentation and the optimum infection was reported at 1×107 cells/ml (cfu).

Keywords : 

Stalk rot, Erwinia chrysanthemi, leaf whorl inoculation, stem injection method, root tip cut dip method, tooth pick method.