Screening Capsicum annuum Accessions for Resistance to Six Isolates of Phytophthora capsici

Abstract

Phytophthora blight caused by Phytophthora capsici Leon. is one of the most important diseases of bell peppers (Capsicum annuum L.) in Georgia. The level of resistance in commercial bell pepper cultivars is not effective in managing this disease in moist and humid conditions, and new sources of resistance are needed. A mixture of six Georgia isolates of P. capsici was used for greenhouse mass screening of 2301 accessions of Capsicum annuum. From the initial screening, 77 accessions were identified as resistant to P. capsici-induced root rot. From those 77 accessions, 28 accessions were selected for seed increase and further replicated root inoculation tests. Replicated tests confirmed the resistance of 14 of the 28 accessions, although genetic variability within the accessions hampered the analysis of resistance in some accessions. Two accessions, PI 201237 and PI 640532, demonstrated consistently high levels of resistance to root rot. These two accessions are potential sources of resistance genes that can be incorporated into commercial bell pepper cultivars.