population biology of magnaporthe grisea and analysis of host plant resistance in foxtail millet against blast disease

Abstract

newline Millets are known as Smart food crops and nutri-cereals . Foxtail millet is the newlinemost nutritive small grained millet. Copious constraints occur during cultivation of newlinefoxtail millet crop, among which blast disease incited by Magnaporthe grisea causes newlineeconomic deprivation to the farmers. Outbreak of foxtail millet blast disease is a serious newlineand recurrent problem in all foxtail millet growing regions of the world and its newlinemanagement is arduous. newlineThe present study consists of collection and isolation of Magnaporthe grisea newlineisolates, characterization through cultural, morphological and molecular approaches, newlineanalysis of genetic diversity using SSR markers, identification of mating type and grass newlinehopper repeat element, correlation and regression analysis of disease severity with newlineweather parameters and identification of resistant genotypes against the blast disease. newlineA detailed survey was undertaken to assess the severity of blast disease of newlinefoxtail millet in the farmer s fields of ten districts viz., Tiruvannamalai, Vellore, newlineDharmapuri, Salem, Erode, Namakkal, Dindigul, Madurai, Virudhunagar and newlineThoothukudi of Tamil Nadu, India. The blast disease was recorded to an extent of 72.19 newlineand 70.16 per cent, respectively in the foxtail millet varieties namely Co(Te) 7 and newlineCo(Te) 5. newlineThirty two isolates of Magnaporthe were isolated from infected plant parts newlinecollected from different foxtail millet growing areas. Among the different culture media newlineused, potato dextrose medium was found to be the best for the growth of newlineM. grisea followed by tenai seed extract medium which recorded significantly the newlinemaximum mycelial growth of 9.0 cm on 15 DAI of the pathogen. Pathogenicity tests newlinewere performed with the field collected isolates of M. grisea on susceptible variety newlineCo(Te) 7. The blast conidia sporulation was not observed on culture media. To get more newlinesporulation of the blast pathogen, stem bits of the weed Paspalum distichum were used newlineas medium. Phenotypic characterization including mycelial growth, colony newlinem