Pollen Viability of Clerodendrum

Abstract

The genus Clerodendrum belongs to the family Verbenaceae of which there are over 400 tree, shrub, and vine species. Species of Clerodendrum vary in leaf size, shape and texture; inflorescence shape; and flower shape, size and color. There is commercial interest in developing hybrids with desirable floricultural attributes. Interspecific hybridization could be used to increase variability in flower color, inflorescence shape, plant vigor, leaf color and shape for selection. Pollen viability among species is in question because of absence of seed set on many selected plants. The need for assessing viability of pollen used is important in determining the strategies to be used in hybridization. Clerodendrum floribundum, C. speciosissimum, C. splendens, C. × speciosum (C. thompsonia × C. splendens) and C. quadriloculare grown in a greenhouse under natural daylight were used as pollen sources. Pollen was collected from recently opened anther, placed in a scintillation vial on ice, and brought into the laboratory. A peroxidase test, dehydrogenase test, and the fluorescein diacetate procedure were used to determine percent viability of pollen before, during and after anthesis for each Clerodendrum species.