Performance of graft combinations of Passiflore spp. under tropical semi-arid conditions in Brazil

The agronomic performance and Fusarium wilt incidence of two yellow passion fruit (Passiflora edulis) varieties (BRS Rubi do Cerrado and HFOP-08) grafted on four rootstocks (HFOP-08, P. nitida, P. alata, and P. gibertii) were assessed in three producing locales under tropical sem-iarid conditions in Brazil (Brumado, Cruz das Almas, and Guanambi in Bahia state; the last two with a history of Fusarium wilt). Non-grafted seedlings were evaluated as controls. Autografted and non-grafted P. edulis plants had similar performance overall. Plants grafted on the alternative species had a reduced growth rate even though the survival rate was 85% (mean life expectancy of 508 days), while mortality caused by Fusarium wilt was high in autografted (98%) and non-grafted (95%) P. edulis plants (mean life expectancy of 191 days). The productivity of the combination P. edulis/P. gibertii was 66% lower in areas free of the pathogen, but 78% higher than the autografted either non-grafted P. edulis plants in areas affected by Fusarium wilt. The wild species were less affected by the disease when used as rootstocks, but P. nitida did not induce adequate plant growth. Fruit quality was not greatly altered by rootstock/scion/locales interactions, but fruit weight, shape and pulp content varied. The leaf concentrations of K, Ca, Mg, B, Mn, and Zn were rootstock-dependent, with increased contents mainly in P. edulis/P. nitida. HFOP-08 presented potential as an alternative yellow passion fruit variety while P. gibertii was the rootstock with the best overall performance under the evaluated conditions.