Black pepper grafting in Piper wild species

Fusarium is the main disease of black pepper (Piper nigrum L.) in Brazil, and grafting using resistant rootstocks can be a sustainable management strategy. Several wild Piper species have been considered resistant to infection. However, further studies on the grafting process are needed to generate a safe technical recommendation for farmers. This research was carried out with the objective of evaluating the initial compatibility of grafting through the interaction between two techniques (top cleft and side cleft) and six rootstocks. The P. nigrum 'Bragantina' was grafted onto four wild Piper species (Piper aduncum Link, Piper tuberculatum Jacq., Piper marginatum Jacq., and Piper hispidum Kunth) and two black pepper cultivars ('Kottanadan Broto Branco' and 'Bragantina'-homograft). P. tuberculatum and P. marginatum were incompatible with P. nigrum 'Bragantina' in the two grafting techniques. There was total suppression of leaf development with incompatible rootstocks inside cleft grafting. The wild rootstocks had twice as many shoots at the base of the seedling than the cultivars in the top cleft grafting. Side cleft grafting was able to suppress by half the shoots at the base of the rootstock, while the aerial part was maintained. Top cleft grafting provided greater survival, shooting, and leaf emission, which was more evident when using P. aduncum species as rootstock, reaching practically twice the shooting (59.3%) in comparison with the side grafting (30.6%). Therefore, the top method and the use of P. aduncum as rootstock for the production of grafted black pepper seedlings is recommended.