Genetic approaches to develop bacterial wilt resistant tobacco cultivars

One of the most notorious pathogens affecting tobacco production is tobacco bacterial wilt (TBW), caused by Ralstonia solanacearum. Controlling TBW is a global issue, and developing more resistant cultivars is one of the solutions. Therefore, this study investigated the effectiveness of recurrent selection (RS) as a breeding strategy to enhance resistance to R. solanacearum in tobacco. We also aimed to identify the appropriate progeny type for RS. The trials were carried out in an area where the pathogen is known to occur, with seedlings inoculated with R. solanacearum to assure the presence of the pathogen. The incidence of the pathogen was evaluated over two seasons. In the first year, we utilized 100 S1:2 progeny from the original population (cycle 0) and 108 half-sib progeny of cycle I. In the subsequent year, we evaluated 196 S0:1 progeny of CI and 176 half-sib progeny of cycle II. Additionally, to ensure the presence of the pathogen, we inoculated R. solanacearum 40–45 days after transplanting the seedlings. The incidence of the pathogen was assessed based on the number of plants showing symptoms (%). Although the difference between cycle 0 and cycle II was relatively small, the results suggest that recurrent selection was successful in accumulating resistance alleles, as reflected in the positive association between disease resistance and agronomic traits.