Evaluation of tomato rootstocks resistant to the fungal wilt disease caused by Fusarium oxysporum f. sp. lycopersici

Fusarium oxysporum f. sp. lycopersici (FOL) is one of the most destructive diseases of tomatoes in Iran, causing severe yield losses and quality reduction. However, not many studies have been conducted to explore the use of resistant rootstocks for managing this disease and minimizing production losses in the region. In this study the level of resistance of multiple tomato cultivars and lines were evaluated against FOL. The most FOL-resistant cultivars were then selected as possible rootstocks and two resistant scions were grafted onto them. FOL was inoculated and the resistance of grafted plants was assessed using several indices, including disease incidence (DI), disease severity (DS), and area under the disease progress curve (AUDPC). In addition, stem length and diameter of the grafted samples were measured. Out of 29 lines and cultivars, only nine, including, Koper, 1616, TOM5, IR.SR3, 1626, 1631, IR.SA1 and the resistant Maxifort and Beaufort check cultivars, found to be the most resistant against FOL and were subsequently used for rootstocks. Koper and 1616 rootstocks exhibited the lowest percentages of AUDPC, DS and DI compared to the grafted plants as well as the susceptible and two resistant checks. They also exhibited relatively greater stem length and diameter. The results in this study suggest the potential of resistant rootstocks in preventing disease progression, which also provide possibilities for control of wilt disease and low-input sustainable horticulture in the region.