Genetic analysis of bacterial wilt resistance in chilli (Capsicum annuum L.)

Bacterial wilt, caused by Ralstonia solanacearum, is a major concern for chilli production, leading to substantial yield losses. As a highly destructive soil-borne pathogen, R. solanacearum poses a significant threat to hot pepper (Capsicum annuum L.) cultivation worldwide. In India cultivated pepper fields, the relentless spread of R. solanacearum is exacerbated by global warming, posing a serious threat to crop productivity. The most sustainable strategy to combat bacterial wilt lies in the development of resistant pepper varieties. However, resistance to bacterial wilt is quantitatively inherited and varies depending on specific R. solanacearum isolates. Thus, this study aimed to assess the inheritance pattern of bacterial wilt resistance by analyzing an F 2 population of 157 plants along with their parental varieties, B-HP-143 and B-HP- 144. In addition, disease reactions in 100 recombinant inbred lines (RILs) from the F 5 population were screened to evaluate disease susceptibility. The severity and progression of bacterial wilt were quantified using the area under the disease progress curve (AUDPC). The analysis of bacterial wilt resistance confirmed a polygenic inheritance pattern in the F 2 population. Several RILs such as, 84, 101, 106, 149, 155, 196, 210, 220, 232, 242, 283, 301, 307, 315, 324, 333, 336, 340, and 342 along with the resistant parent B-HP-143, exhibited complete resistance to bacterial wilt with no signs of infection. In contrast, B-HP-144 displayed a 70% incidence of bacterial wilt. The calculated AUDPC value for the F 2 generation was 545.54, while B-HP-143 and B-HP- 144 had values of 0.00 and 735, respectively. These results highlight B-HP-143 as a promising source of high resistance. The incorporation of resistant RILs into breeding programs can greatly enhance the development of bacterial wilt-resistant hot pepper varieties. The findings of this study provide a crucial foundation for integrating bacterial wilt resistance into elite commercial hot pepper genotypes, contributing to future crop improvement efforts.