Challenges associated with micropropagation of Zephyranthes and Hippesatrum sp. (Amaryllidaceae)

Summary Conventional propagation of amaryllis, Hippeastrum Herbert sp. hybrids by bulb offsets is slow, seasonal, and variable; additionally, some amaryllis hybrids do not produce many offsets. From seed, it takes approximately 2 yr to flower. Micropropagation of Zephyranthes L. sp. bulbs has challenges related to contamination of stage I cultures as well as genotype differences in culture media requirements. There are literature reports on in vitro propagation of both genera; however, the application of these reports to new cultivars leaves unanswered questions regarding surface disinfestation, explant, nutrient media, and multiplication rates. Surface disinfestation of container-grown Hippeastrum spp. hybrid cv. San Antonio Rose bulbs resulted in contamination rates of 20 to 100% in spite of various treatments, some of which killed the explant. Twin scale explants of San Antonio Rose bulbs responded on a Murashige and Skoog salt medium with 2 mg naphthalene acetic acid per 1, and transfer to soil was not a problem. In contrast, aseptically germinated seed of Zephyranthes sp. served as a suitable source of clean bulb tissue.