FACTORS AFFECTING THE HORMONE-INDUCED SETTING OF COX APPLE

Experiments were carried out on mature Cox's Orange Pippin trees on M9 rootstock. In 1980, pollination was prevented by the use of decapitated flowers: In other years, enclosing the trees in muslin cages stopped cross-pollination. Bourse clusters and clusters on 2yr wood were reduced to two flowers in 1980, and all clusters to one flower in other experiments. The hormone mixture, containing 200ppm gibberellic acid, 300ppm NN'-diphenylurea and 50ppm 2-naphthoxyacetic acid was applied as an aqueous spray at petal fall in all experiments, except those in which times of application were being compared.