Flowering in the sweet orange.

Abstract

Anthesis in Navels and Valencias in the Mildura district normally takes place over a period of 5-6 weeks from late September to the end of October. The first flowers to open are terminal (distal) on leafless shoots. Flowers on leafy shoots are generally open about I week later. Terminal flowers open early, except solitary flowers on leafy shoots. The lowest (proximal) buds are next to attain anthesis, and subterminal flowers are last. Late-opening flowers have a better chance of producing fruit than those which open early, and in consequence most fruit are developed from subterminal flowers, or from those buds just below the subterminal. Most fruiting flowers open not earlier than the fourth week of the flowering season. Flowers which are slow to reach anthesis, but do not produce fruit, remain on the tree longer than flowers which develop early. Drop of flowers after blossoming is a continuous process; there does not appear to be any particular time or period of development which is critical. Flowers on the shaded side of the tree open about 1 week later than those exposed to the sunshine, but this does not result in a better set of fruit on the shaded side.