Dormência da nogueira-pecã (Carya illinoinensis (Wangenh) K. Koch) pelo método biológico

Abstract

The climate is one of the main factors influencing the development of the pecan tree, and the cold during the dormancy period is one of the limiting reasons, since, according to the literature, the pecan tree needs low temperatures to be able to induce and overcome dormancy and then start a new growth cycle. Problems related to lack of cold present themselves with different intensities. Thus, the objective of the study was to estimate the need for cold hours to induce bud sprouting in different pecan cultivars submitted to natural cold and to evaluate the response of cultivars subjected to artificial cold, using the biological method with cuttings of isolated nodes. For the objectives to be met, three studies were carried out. The first consists of a literature review that is focused on addressing dormancy in culture. In the second study, an experiment was carried out to evaluate the cooling requirement of seven pecan cultivars (Farley, Success, Barton, Desirable, Jackson, Mohawk and Melhorada) submitted to natural cold, with monthly collections carried out from June to September 2019. In the third, the response of 12 cultivars (Success, Shoshoni, Farley, Elliott, Mohawk, Jackson, Desirable, Barton, Importada, Shawnee, Choctaw and Melhorada) was evaluated, exposed to artificial cold, where 0, 250, 500, 750 and 1000 hours of cold, in the years 2017 and 2018. The chilling requirement of the pecan cultivars surveyed in the studies varies with the approach and in the developed location, not showing a consensual and definitive pattern. Based on the results obtained, it is possible to conclude that the cultivar Mohawk is more demanding in terms of cold and the need for cold of the other cultivars varies between the years of evaluation, making it necessary to conduct more studies. Furthermore, it was possible to conclude that perhaps the test of isolated knot cuttings is not the most adequate method to determine the chilling requirement of the pecan tree