Understanding Reaction of Potato (Solanum tuberosum) to Ralstonia solanacearum and Relationship of Wilt Incidence to Latent Infection

Bacterial wilt caused by Ralstonia solanacearum is one of the most important diseases affecting more than 200 plant species, including solanaceous crops. The pathogen is known to cause complicated symptoms ranging from visible to latent ones. Understanding crop's reaction to the pathogen and the underlying relatedness of latent infection to wilt incidence is of paramount importance. Thus, a number of potato cultivars including improved and otherwise were evaluated under greenhouse and field conditions. Accordingly, twenty‐eight of the cultivars tested under greenhouse conditions were resistant to the pathogen with scores ranging from 0.77 to 1.17 of 5. Nonetheless, under field conditions, only 2 of 28 cultivars found to be ‘resistant’ under greenhouse conditions, showed adequate resistance to the pathogen, indicating the significant impact of environment on the activity of the pathogen and reaction of the crop. Percentage wilt incidence and latent infection showed significant (P < 0.05) positive correlation, with r = 0.9438. Thus, evaluation of crop's performance based on the combination of the parameters like field wilt incidence and proportion of latent infection gave us better picture of the overall crop feat, than using wilt incidence as a sole parameter of evaluation as has been the case in most studies. Moreover, the established correlation of latent infection with field wilt incidence will also help us understand the disease epidemiology and design effective management measures, accordingly.