Banded sheath and leaf blight (BSLB) disease resistance Screening and biochemical responses of baby corn and sweet corn lines

Abstract

Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice. Apart from being used as grain, animal feed, for production of corn ethanol, starch, syrup etc. it has been widely used as vegetable in the form of baby corn and sweet corn (Zea mays L.). Rhizoctonia solani causes banded sheath and leaf blight (BSLB) disease in baby corn and sweet corn. Worldwide, the disease causes huge economic losses. Use of resistant cultivars is among the most effective, economic and environmentally safe strategy. To identify resistance source, 47 baby corn and 35 sweet corn inbred lines were screened under field conditions as well under artificially controlled condition following artificial inoculation. The experiment was conducted during the kharif season of 2017-18 at ICAR-IIVR, Varanasi. Out of 82 inbred lines IIVRBC-13 and CML-323 gave resistant and moderately resistant disease responses respectively and rest of the germplasm lines gave susceptible responses. Biochemical analysis revealed higher content of lignin, phenol, protein and carbohydrate in resistant (IIVRBC-13) and moderately resistant (BC-62) germplasm in comparison to highly susceptible (IIVRBC-19) germplasm. The findings indicate presence of high level of pre-infectional barriers in the resistance lines. Further, higher level of defence related enzymatic activities of peroxidase and poly phenol oxidase between 24 hour to 72 hours of post inoculation were detected in the resistant inbred lines. Similar trend was observed for level of electrolyte leakage also. Whereas, the relative water content first declined in around 24 hour post inoculation and it shoots up near 48 hours post inoculation. The study clearly shows the presence of effective pre-infection barriers and induced biochemical defence mechanisms operating in the resistant inbred lines. Identified resistant lines can be used in BSLB disease resistance breeding programmes.