Abstract
The main objective of this research was to elucidate the flowering, fruit drop patterns and fruit set in Tankan (Citrus tankan Hayata) ‘Tarumizu 1 go’ to determine the physiological and environmental effects and how they relate to tree productivity. Fruiting shoots were separated on the basis of the number of subtending leaves, (leafy and leaf-less flowers) and data on flower emergence and fall patterns were collected. The results obtained showed that normal distribution curve of flowering, starts at end of April and peaking in mid-May. Tankan has flower types that range from those that have no new leaves subtending them (leaf-less flowers) to those that have up to 7 leaves. In terms of flowering, leaf-less flowers and flowers having up to 3 leaves flowered much earlier than flowers having 4 or more leaves. Two flower/fruit drop peaks were observed. The first one occurred from end of April and peaking in mid-May and the second one was of less intensity and occurred 40 to 60 days after anthesis and peaking in mid-June. The drop of flower bud was reduced to very low values. Although leaf-less flowers made up more 50% of the total flower number most of them abscised and less than 1% of the leaf-less flower set fruit. For leafy flowers, fruit set increased with increase in number of leaves. Comparatively more flowers dropped in the first fruit drop cycle than in the second fruit drop cycle. The results illustrated the importance of leafy flowers in ensuring high fruit set and productivity.
