DUGi

Compositional analysis of correlation of weather parameters with russet of ’Golden Delicious’ apples

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The development of russet on ’Golden Delicious’ apples is a problem of concern to growers of freshmarket apples. Russeting is considered to be due to untimely divisions of cells in the epidermis of thefruit initiated by environmental or cultural conditions. The etiology of nonculturally induced russetis intimately associated with the presence of water on the surface of the fruit. The initiation of russetclearly occurs during the first 30 days of fruit development, and is frequently visible at the end ofthat period. Creasy (1980) concluded that high relative humidity was positively correlated with thedegree of incidence of russeting, especially 16-25 days after full bloom of apple trees. This study wasconducted to establish the correlation between weather parameters and the incidence of russeting onapples.We have recorded the incidence rates of russeting on ’Golden Delicious’ grown in ’Mas Badia’ fieldstation (La Tallada, Girona), from 1986 to 2002. Each year a sample of apples was picked at random.Each fruit was evaluated for the percent of surface area covered with russet which was categorizedinto five ordinal categories. In this way we have the percentage of each russeting-category for eachyear. Simultaneously we have the annual meteorological data recorded hourly at the meteorologicalstation of ’Mas Badia’. From this information we will use CODA to analyze the correlation betweenthe annual percentages of russeting in apples and the humidity and rainfall recorded during the 30days after full bloom of apple trees in the corresponding year

Universitat de Girona. Departament d’Informàtica i Matemàtica Aplicada