Pecan cultivation in Puglia region, southeastern Italy: fruits and truffle production

In Italy, suitable pedo-climatic conditions for pecan (Carya illinoinensis (Wangenh.) K. Koch) cultivation can be found in the Po Valley, Puglia, and Sicily regions. Considering the rising interests of growers and consumers for healthy food and diversified diets, pecan has the potential to be an alternative and valuable fruit crop to diversify fruit production. However, there is very limited scientific information regarding pecan cultivation in Puglia or other regions with similar pedo-climatic conditions in Italy (Mediterranean climate). The aim of this study was to 1) evaluate a few quantitative and qualitative characteristics of fruits selected from established pecan cultivars over two years, and 2) conduct preliminary studies to assess the potential of pecan seedlings (‘Shoshoni’ and ‘Shawnee’) as suitable to establish ectomycorrhizal symbiosis with truffles (Tuber borchii, T. aestivum and T. melanosporum) collected in Puglia. During the two-year-long investigation, mature ‘Wichita’, ‘Shoshoni’, ‘Stuart’ and ‘Pawnee’ pecan trees reached yields as high as ≈30 kg tree-1 in the ‘on’ year, and a kernel dry weight >3 g, with lower values in the ‘off’ year. The other cultivars investigated (‘Shawnee’, ‘Choctaw’, ‘Cheyenne’, ‘Green River’, ‘Kiowa’, ‘Mohawk’, and ‘Peruque’) showed lower yields and stronger alternate bearing, with a very low production in the ‘off’ year. Kernel percentage was higher than 50% and in-shell dry weight between 5 and 7 g for many cultivars. The mycorrhization positively affected both plant height and stem diameter, and to a lesser extent the number of leaves and the SPAD values. The rate of mycorrhization assessed 12 months after the inoculation was greater than 50%, thus indicating that ‘Shoshoni’ and ‘Shawnee’ pecan seedlings are suitable hosts to establish ectomycorrhizal symbiosis with T. aestivum, T. borchii, and T. melanosporum cultivation under Puglia climatic conditions. The cultivation of pecan, especially of plants mycorrhized with commercial truffles, could be an important alternative to recover the rural marginal areas in Mediterranean regions and to improve organic farming production, sustainability, and biodiversity.