Analysis of pathotypic variability of Xanthomonas oryzae pv.oryzae, the bacterial blight pathogen of rice and identification of new sources of resistance

Abstract

Bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is becoming a major production constraint worldwide. In India, the disease is causing considerable yield loss in all rice producing states. In Kerala, the disease is appearing in an epidemic form in recent years in Palakkad, Thrissur and Alappuzha districts. Host plant resistance offers a viable option for the management of the disease. Understanding the pathogen population prevailing in a geographical area is essential for the development of varieties having broad spectrum resistance. The present study was undertaken to analyse the pathotypic variability of Xoo in major rice growing areas of Kerala and to identify new sources of resistance.