INFLORESCENCE TYPES AND FRUITING PATTERNS IN HAMLIN AND VALENCIA ORANGES AND MARSH GRAPEFRUIT

The structural, flowering, and fruit-setting patterns of inflorescences of mature Hamlin and Valencia orange and Marsh grapefruit trees were studied for three years. Several development patterns were found, some of which were relatively consistent for the different varieties or years of study. The sequence of anthesis on an inflorescence was: apical flower first, then basal flower, then the subapical flower. Terminals on which the earlier flowers appeared tended to have more inflorescences than those on which flowers appeared later. Inflorescences on which earlier flowers appeared also produced more flowers than those which began flowering later. Inflorescences that began flowering later were more likely to have leaves or have a greater number of leaves than earlier inflorescences. More than half of the inflorescences carried no leaves, and most of these had one flower. No evidence of a relationship between number of flowers and length of the inflorescence was found. Fruit set occurred primarily during the latter part of the flowering period. Many fruit were set on inflorescences without leaves, but on the basis of percent of flowers setting fruit, inflorescences with leaves were more productive. The greatest fruit set occurred in the subapical position on the inflorescence. With growth changes these fruit often appeared to be developing in the apical position. These patterns generally differed little from year to year. Variations may have been due to the differences in the number of flowers produced by the trees. Results were also similar between Hamlin and Valencia oranges. Patterns on Marsh grapefruit resembled those for the oranges but were frequently less consistent.