AN EFFICIENT AND QUICK in-vitro METHOD OF EVALUATION OF POTATO GENOTYPES AGAINST Ralstonia solanacearum
KAJAL THAKUR
Central Potato Research Institute, Shimla, H.P., India and Lovely Professional University, Phagwara, Punjab, India.
VINAY SAGAR
Central Potato Research Institute, Shimla, H.P., India.
SUNDARESHA SIDDAPPA *
Central Potato Research Institute, Shimla, H.P., India.
NEHA SALARIA
Central Potato Research Institute, Shimla, H.P., India and Lovely Professional University, Phagwara, Punjab, India.
UMESH GOUTAM
Lovely Professional University, Phagwara, Punjab, India.
SANJEEV SHARMA
Central Potato Research Institute, Shimla, H.P., India.
*Author to whom correspondence should be addressed.
Abstract
Potato is an important food crop and its seed production has zero tolerance policy for bacterial wilt caused by Ralstonia solanacearum. It is a soil-borne pathogen which can limit potato production and cause high yield losses. The prerequisite for the development of wilt resistance is efficient method of evaluation of germplasm against R. solanacearum. In present study, an in-vitro bioassay was developed for screening the potato genotypes for R. solanacearum resistance. The resistance against wilt was checked in wilt resistant and susceptible potato plants. The resistant plants showed resistance to R. solanacearum for a prolonged period as compared to control plants which started wilting after two days of inoculation. The resistance was validated through bacterial count and virulence analysis. The results revealed bacterial count was high in control plants and low in resistant plants. Avirulent colonies were obtained for resistant plants while susceptible (control) plants showed virulent colonies. These results showed that the developed in-vitro bioassay can be used successfully in detecting and evaluating germplasms resistance against R. solanacearum. Therefore, the advantage of this in-vitro method makes it quick, simple and feasible in lab. The method also ensures containment of pathogen avoiding escape and does not provide false positive results. This method will help in identification and screening of large number of germplasm against R. solanacearum and help in future efforts for development of wilt resistant potato varieties.
Keywords: Ralstonia, in-vitro screening, virulence, potato