Fruit colour and correlations with orchard factors and post-harvest characteristics in apple cv. Mutsu

Abstract

SummaryTo improve the quality of `Mutsu' apples after storage, relationships were studied between various orchard factors and fruit quality in an orchard survey performed in 1996 and 1997. Quality aspects included were fruit colour as related to fruit firmness and contents of starch, sugar and acid. Fruit colour was strongly correlated with firmness and sugar content, whereas starch and acid content correlations were not consistent from green to intermediate and yellow fruit. Compared with 1996, yields were higher and the development of fruit colour poorer in 1997, probably caused by climatic variations. No correlations were found between ratings for tree density, tree vigour and tree openness vs. fruit colour, whereas crop load was highly correlated to both green, intermediate and yellow fruit colour, respectively. In addition, significant correlations were found between leaf N, leaf K, and fruit colour. It is suggested that possible cultural practices for obtaining good fruit quality of `Mutsu', therefore, may be a low to moderate supply of nitrogen, a relatively high supply of potassium and thinning to achieve an optimal crop load.