Performance of eggplant cultivars grafted on wild and cultivated rootstocks in bacterial wilt infected field

ABSTRACT Bacterial wilt (BW) causes extensive loss in yield of eggplant (Solanum melongena L.) under tropical and humid subtropical conditions. Grafting commercial cultivars onto selected rootstocks is an effective approach to control wilt disease without requiring extensive breeding to develop resistant varieties. Wild and cultivated eggplant genotypes were screened for tolerance to BW disease (Ralstonia solanacearum Biovar IIIA) in artificially created infested beds. Two each of S. torvum Sw. genotypes (BCB ST 1 and IARI ST 1) and cultivated varieties ‘Utkal Anushree’ and ‘Utkal Madhuri’ were identified as most compatible (graft survival was high) rootstocks. Two widely cultivated, susceptible cultivars, ‘Bidhan Suphala’ and ‘Bidhan Supreme’ were grafted as scions on rootstocks and reproductive growth, fruit quality and disease incidence of grafted plants in the bacterial wilt infected experimental and grower fields determined. Although grafted plants had lower mortality and higher yield, fruit quality was not improved. Solanum torvum Sw.-grafted plants exhibited some negative effects on yield and economics compared to cultivated rootstocks, indicating reduced post-transplant compatibility. The ‘Bidhan Suphala’ grafted on cultivated rootstock ‘Utkal Anushree’ had the highest yield and economic return than those grafted on wild rootstocks. ‘Utkal Anushree’ could be effectively used as a rootstock for controlling eggplant wilt through grafting. Grafting eggplant cultivars on rootstock of a cultivated variety over wild species increased yield, extended the harvest and was effective in reducing crop loss caused by BW disease.