Characterization and Flowering Behavior of Eleven Philippine Native Phalaenopsis Species and Gamma Irradiation Effects on Phalaenopsis aphrodite

Abstract

Eleven species of Phalaenopsis or butterfly orchids collected from different places in the country were characterized for flower traits, leaf characters, growth habit, and capsule maturity, length, and width; evaluated for flowering behavior; and tested for self-compatibility and capsule setting under ambient conditions in Los Baños, Laguna, Philippines. Also, Phalaenopsis aphrodite was used for mutation breeding via gamma irradiation. Subjecting self-fertilized progenies to irradiation will generate mutants with potential for breeding and selection. The eleven Phalaenopsis species studied flowered consistently under ambient conditions for two years with degrees of self-compatibility and capsule setting varying from 3.8 to 50%. P. aphrodite and P. hieroglyphica embryos cultured in vitro germinated successfully at 80–90% within 3–4 wk after explanting. Germinating embryos of P. aphrodite subjected to different levels of gamma irradiation at 10, 15, 20, and 25 Gy responded differently to the treatments. The number of complete regenerants, and those regenerants with shoot only, also differed significantly among the treatments. In addition, leaf length, width, and thickness differed significantly among the treatments after 2 yr of growth. Early flowering was observed in two plants of P. aphrodite irradiated using 15 Gy. Normally, tissue culture-derived P. aphrodite seedlings flower 3 yr after potting out, but one plant flowered at 1 yr and 8 mo while the other did at 2 yr after potting out.