Ameliorating effect of zinc and manure application on the growth of Macrophomina phaseolina (Tassi) goid infected genotypes of Arachis hypogea L.

Peanut [Arachis hypogea (L.)] is a valuable legume crop that is widely cultivated in Northern Nigeria. The yield of this crop is affected by root rot disease caused by the fungal pathogen (Macrophomina phaseolina). This study was carried out to assess the efficacy of Zinc (Zn) (1.76, 3.59, 4.71 and 6 mg kg(-1)) and Manure [M (2% and 4%)] in a complex interaction to manage the disease and improve yield. Two genotypes of peanut were selected for this study on the basis of their susceptibility to M. phaseolina (severely infected UGA 2) and (moderately infected ICGV 86015). The results showed that M. phaseolina suppressed the plant defense action through the activities of malionaldehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) thereby hindering identification of the pathogen elicitor. It was observed that manure enhanced the microbial activity and physicochemical properties of soil, which induced plant defense and antimicrobial protein against reactive oxygen species (ROS) thereby reducing the susceptibility of the pathogen to the peanut plant. The co-factor ability of Zn enhanced the activities of antioxidant enzymes to scavenge ROS molecules in the pathogen stressed cells, improve photosynthetic efficiency and prevent the plant from death. Therefore, this study has revealed that Zn and manure inhibits the multiplication of M. phaseolina in the peanut seedlings.