FLORAL BIOLOGY AND BREEDING-BEHAVIOR IN THE BAMBOO DENDROCALAMUS-STRICTUS NEES

Floral biology and breeding behavior were studied in the bamboo Dendro calamus strictus Nees. The inflorescence in this species is a large br anching panicle. Fertile florets are intermixed with smaller sterile o nes. There are six stamens. The ovary is stipitate and turbinate. The style is long and the stigma is bifid and plumose. Dendrocalamus stric tus is typically dichogamous and protogynous. The gynoecium matures 3- 4 days before the androecium, effectively preventing self pollination. Flower bloom, which took place over a period of 2 to 3 h, was depende nt on air temperature and only occurred between 0600 and 1300 h. Dendr ocalamus strictus is anemophilous. Flowers in the male phase were visi ted by insects. These insects completely neglected the flowers at the female phase. The insects fed on the pollen and were not pollen vector s. When wind was excluded by enclosing the inflorescences in bags ther e was no seed set, indicating that cross pollination by wind is necess ary for fertilization and that parthenocarpy and apomixis are not occu rring in this species. Pollen fertility was about 98% as indicated by staining fresh pollen at the time of anther dehiscence and pollen rele ase with Alexander's stain (Alexander 1969). When placed on a modified Brewbaker-Kwak medium containing 1% glucose, the pollen grains germin ated well, and the pollen tubes grew to 15-20 times the diameter of ma ture pollen grains. Although profound protogyny has its disadvantages in times of sporadic flowering, it can be useful in breeding programs because it eliminates the need for emasculation.