Potential of Hawaii 7996 hybrid as rootstock for tomato cultivars

Grafts have been used in horticultural crops, to overcome soilborne plant pathogens, and thus minimize yield losses of susceptible cultivars. This work aimed at to evaluate growth and yield of tomato plants grafted on to a hybrid resistant to Ralstonia solanacearum, as compared to non-grafted seedlings. Seedling production and grafting were done in nursery and grafted plants essayed Cruz das Almas, State of Bahia, Brazil, from October of 2003 to February of 2004. Cleft graft was used on to Hawaii 7996 hybrid as rootstocks, and Santa Clara, Santa Cruz Kada and Debora Plus, susceptible to the disease were used as scion. The experimental design was a completely randomized blocks with six treatments and five replicates (3 scion-rootstock combinations and 3 types of non-grafted seedlings). The following characteristics were evaluated: stem diameter, plant and first inflorescence height, distance between inflorescences and commercial fruit yield. Plant growth, average fruit weight and yield did not differ between grafted treatments and non-grafted seedlings. There was no incompatibility between the rootstock and the scion plants. Santa Cruz Kada showed more sensitivity to the agroecological conditions of Cruz das Almas, which reflected negatively in the yield and average fruit weight. The hybrid Hawaii 7996 is a promising rootstock allowing the growth of tomato crop bacterial wilting susceptible cultivars, in areas infested with R. solanacearum.