Some factors influencing flowering and fruit-set of clementine mandarin

A four-year research study conducted in center Sardinia on clementine mandarin has evidenced that flowering and subsequent fruit-set can be affected by several factors, i.e., growth substances, light intensity and temperature before flowering. Particularly it has been shown that gibberellic acid sprayed during flower differentiation reduced the number of flowers/ square meter of canopy,but increased the number of leafy inflorescences and the fruit-set percentage. Alar sprayed in the same conditions increased the number of flower/square meter and reduced the number of leafy inflorescences and the fruit-set percentage. Low light intensity obtained by shading trees with large cages covered with nets of black nylon decreased the number of flowers and leafy inflorescences, but no clear effects were found on the fruit-set percentage. Warm temperatures before flowering increased the number of flowers/square meter, but decreased the fruit-set percentage.