Effects of preharvest weather conditions on firmness of 'McIntosh' apples at harvest time.

摘要

Apple fruit firmness is 1 of the main attributes indicating fruit quality at harvest. It is affected by numerous factors during the entire growing season. Effects of weather conditions during apple development are often mentioned as a result of their impact on attributes linked to fruit firmness: fruit size, Ca concn., water content, etc. In this study, effects of weather conditions on McIntosh apple firmness at harvest time were analysed. Fruit were harvested at 9 sites in Quebec and Ontario, Canada, over 15 yr (1996-2011). For each case, weather parameters were analysed from full bloom until harvest, either in monthly subperiods from May until Sept. or in terms of days from full bloom (DFB) until harvest. Regression results highlighted the negative effect of lower air temp. conditions from 31 to 60 DFB, higher air temp. conditions and precipitations from 61 to 90 DFB, and higher temp. conditions from 91 DFB until harvest on McIntosh apple firmness level at harvest. Precipitation from 61 to 90 DFB alone explained 39% of McIntosh apple firmness variation at harvest time. Prediction of apple firmness at harvest time could be helpful for producers to adjust their marketing and storage strategies according to apple quality level.