Phenological evaluation of different fruiting habits of 'Gala' and 'Fuji' apples in the Southern Brazil/Avaliacao fenologica das diferentes estruturas de frutificacao das macieiras 'Gala' e 'Fuji' na regiao de Cacador-SC

Apple shows two distinct phases that characterizes its annual cycle: dormancy and vegetative/ reproductive growth. The importance of knowing the influence of climate conditions on tree reproductive processes and furthermore, developing technologies that minimize the future effects increases upon the global warming predictions becomes concerning. The goal of this study was to characterize the behavior of the main phenological events of apple, from bud break to harvest, on different fruiting habits under the subtropical climatic conditions of the South of Brazil. The experiments were carried out on nine year old 'Gala' and 'Fuji' apples in the Experimental Station of EPAGRI (Brazil--26°50'S, 50°58'W, altitude 950m) during two different growing seasons, 2011/12 and 2013/14. Date and days after dormancy breaking treatment and heat requirements of the main phenological stages from bud break to harvest were evaluated. Evaluations were performed on each fruiting habit: spur buds, terminal and axillary buds on long shoots. Differences found on the onset of bud break and flowering among fruiting habits greatly depended on climate conditions of the particular year. High temperatures conditions after the dormancy breaking treatment induced to a phenological synchrony among fruiting habits, and vice versa. From dormancy breaking treatment, spur buds, especially 'Gala' buds, required less heat accumulation to bud break. Terminal buds of long shoots required higher amount of heat than spur buds to start flowering. Index terms: Malus domestica Borkh., degree-days, bud break, flowering. A macieira apresenta duas fases que caracterizam seu ciclo anual: a de repouso hibernal e a de crescimento vegetativo e reprodutivo. A importancia em se conhecer a influencia das condicoes climaticas sobre os processos reprodutivos das plantas e em desenvolver tecnologias que minimizem os possiveis efeitos aumenta a medida que as projecoes de aquecimento global se tornam preocupantes. O objetivo deste trabalho foi caracterizar o comportamento dos principais eventos fenologicos da macieira, da brotacao a colheita, nas diferentes estruturas de frutificacao, sob as condicoes climaticas do Sul do Brasil. O estudo experimental foi conduzido na Estacao Experimental da Epagri (26°50'S, 50°58'W, altitude 950 m), durante os ciclos de 2011/12 e 2013/2014. As cultivares estudadas foram Gala e Fuji, com nove anos de idade, ambas sobre o porta-enxerto M9. O desenvolvimento fenologico foi observado nas