Fruit set in some species of citrus is greater on mixed shoots (leafy inflorescences) than on generative shoots (leafless inflorescences). Combination treatments involving water stress, cool winter night temperatures, and branch pruning were used to manipulate the number of shoots and ratios of the three shoot types in containerized `Tahiti' lime (Citrus latifolia Tan.) plants. Plants were water stressed in a greenhouse for five weeks, pruned after rewatering, transferred to the open environment, and observed three weeks later. Appropriate control plants were carried along with treated ones. Combination treatments of all three variables increased the number and ratio of mixed shoots four fold over the non-stressed, non-pruned controls. More shoots formed on non-pruned, water stressed plants than on controls. Both formed predominantly generative shoots. Shoots of pruned, non-stressed plants were predominantly vegetative. Non-pruned non-stressed plants were typical of those growing in the field exposed to cool winter nights.
T. L. Davenport and M. Codallo
A.A. Abdul-Baki, H.H. Bryan, G.M. Zinati, W. Klassen, M. Codallo, and N. Heckert
Prolific flowering is essential for economic seed production in sunn hemp (Crotalaria juncea L.). Since flowers appear as racimes on the distal portions of secondary branches and since the branching is restricted by a strong apical dominance, lifting the apical dominance by cutting the tops of plants should induce more branches and more flowers per plant. We evaluated this concept in a field experiment conducted in 1999 at the Tropical Research and Education Center, Univ. of Florida, Homestead, by cutting main stems of 100-day-old plants in a dense stand (113,000 plants/ha) at 30, 60, and 90 cm above the soil surface. Cutting at all heights induced more branching and flowering than the control. The highest positive response was in plants in which the main stem was cut at 90 cm above soil surface.