CPPU control of fruit morphogenesis in apple

Abstract

CPPU, a cytokinin-like substance derived from phenylurea, was applied to shoots, fruits, and to shoots + fruits of mature trees of apple cultivars ‘Golden Delicious’ clone B and ‘Red Delicious’ clone Clear Red 25 days after full bloom. While no influence on fruit morphogenesis was detected for the shoot only treatment, the fruit only and shoot + fruit applications enhanced fruit size and weight, though often inducing irregular elongation, a slight delay in colouring and a lower sugar content. No differences were recorded in the contents and degradation of pectic substances.