Early growth of pecan cultivars under organic production

Organic pecan production may offer not only a chance to increase economic returns-due to its increased product value-but also to avoid pesticide applications. This contributes to the growth of residue-free food and protects the environment. However, there is limited data on the performance of pecan cultivars in ecologically-based systems, especially regarding growth and susceptibility to scab (Venturia effusa) during the early developmental stages of orchards. This study aimed to evaluate the early growth of pecan cultivars in an organic production system in Pelotas, Rio Grande do Sul State, Brazil. The cultivars evaluated were Melhorada, Imperial, Success, Importada, Barton, Farley, Shawnee, Chickasaw, Desirable, Cape Fear, Choctaw, Elliot, Mahan, Sioux, Stuart, and Sumner. Their phenology, vegetative growth, and susceptibility to scab were assessed from 2018 to 2022. Sumner, Stuart, Desirable, Success, and Imperial exhibited the highest early growth under experimental conditions. Chickasaw, Desirable, Sioux, and Cape Fear were the most precocious cultivars in terms of bud break, while Barton, Farley, Stuart, and Sumner were the latest. In terms of scab susceptibility, Cape Fear, Chickasaw, Choctaw, Mahan, and Sioux were the most susceptible cultivars, whereas Barton, Elliot, and Stuart were the least susceptible under experimental conditions. In the early stages, Barton, Elliot, Success, Stuart, Sumner, Desirable, and Imperial were the standout cultivars in the organic production system.