Assessment and Validation of Resistance to Bacterial Wilt ( Ralstonia Solanacearum ) Through Field and Molecular Studies in Bell Pepper

Bacterial wilt, caused by Ralstonia solanacearum species complex, is one of the most serious and widespread diseases across the globe. No single control method has yet been effective against this pathogen despite the use of several control strategies. The best approach to manage this disease is breeding for resistant varieties, which requires the identification of resistant sources and continuous pathogen screening. There is a lack of knowledge about resistance to bacterial wilt in the available pepper germplasm in India, despite the availability of identified molecular markers for marker-assisted selection of resistance against bacterial wilt. The objective of this study was to assess the degrees of resistance of 21 bell pepper genotypes grown in R. solanacearum contaminated field soils by evaluating the disease incidence per genotype and validate the results by PCR using specific SSR primers associated with bacterial wilt resistance, marker CAMS 451. Those genotypes were previously developed through hybridization with bacterial wilt resistant lines. Two parental resistant lines were included as resistant controls and "California Wonder" variety as susceptible control. Sixteen of the genotypes evaluated showed variable high-level resistance evidenced by disease incidences below 13.33%, while four lines were completely resistant with zero disease incidence. The genotypes were confirmed by PCR. Further, the fruit yield data for the mentioned genotypes was assessed under field conditions which showed a heterotic effect in the recombinants over the parental genotypes. In summary, these genotypes could be used as donors in developing new disease-resistant bell pepper varieties which contribute to the availability of resistant bell pepper germplasm to bacterial wilt.