Screening of sorghum genotypes and biochemical changes for resistance to damage caused by Macrophomina phaseolina

Abstract

Charcoal rot, caused by Macrophomina phaseolina, is the most common yield reducing constraint in sorghum. In the present study, eight cultivars of Sorghum bicolor were screened against M. phaseolina to determine its effects on several growth parameters as well as the content of phenols, salicylic acid (SA), total protein and peroxidase activity and were examined for their relationship, with disease resistance. Out of the eight cultivars tested, PJ-1430 was the most resistant and SU-1080, the most susceptible. The roots of plants were more affected by the pathogen than the shoots. The cultivar PJ-1430 produced a higher plant root and shoot dry mass and was associated with higher polyphenols, SA, peroxidases and thus sustained less oxidative damage whereas SU-1080 experienced maximum oxidative damage, so was considered susceptible to charcoal rot. A positive relationship was observed among various biochemical parameters and disease resistance of cultivars PJ-1430 and SU-1080.