Genetic resistance and silicon in the control of stem rot in Capsicum spp.

Abstract

Pepper stem rot is a disease caused by Sclerotium delphinii, a necrotrophic pathogen and a natural soil inhabitant. Identifying genotypes of Capsicum resistant to the pathogen and applying silicon (Si) can be effective management measures. The objective of the study was to identify sources of resistance in 24 accessions of Capsicum spp. against S. delphinii, and to evaluate the potential of sodium silicate (Si) to induce resistance. Two experiments were conducted: In Experiment I, the resistance reaction of Capsicum in a greenhouse was evaluated. The experiment was conducted in two periods of the year (July and November 2019). In Experiment II, the effect of Si on Capsicum resistance was evaluated. The experimental design used in Experiment I employed randomized blocks in a factorial design of 2 (isolates) x 24 (accessions), with five replications. For Experiment II, six accessions were selected with contrasting resistance responses observed in Experiment I, in a factorial design of 1 (isolate) x 6 (accessions) x 4 (doses: 0.0, 0.025, 0.05, and 0.1 mL per vase). Accessions BGH 71 and BAGC 134 showed greater resistance to the pathogen. Accession BAGC 134 demonstrated high resistance stability in both periods and against the two isolates tested. Si doses had no significant effect on the resistance reaction. Therefore, the genotypes BGH 71 and BAGC 134 have the potential to be used in breeding programs for Capsicum for resistance to S. delphinii for control of stem rot.