Renato A. Avenido, Liza Farah A. Tisalona, and Evelyn Mae T. Mendoza
Institute of Plant Breeding
University of the Philippines Los Baños
doi.org/10.57043/transnastphl.1997.5944
Abstract
The first success in developing regeneration systems via somatic embryogenesis and shoot organogenesis in avocado (Persea americana Mill.) which are suitable for Phytophthora cinamomi resistance selection in vitro are reported. Direct shoot regeneration was achieved from shoot tips or meristems excised from axillary buds cultured initially on MS medium supplemented with 0.5 mg/L BAP and 0.1 mg/L NAA and subcultured on the same medium or with BAP in combination with 0.5 mg/L thidiazuron (TDZ). Increasing sucrose concentration of 70 g/L reduced the incidence of browning and improved shoot growth favoring the formation of multiple shoots.
Embryogenic calli were obtained from immature seeds of avocado cv RCF Purple cultured on modified Murashige and Skoog (MS) medium supplemented with 5.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and 1.0 mg/L 6-benzylaminopurine (BAP). Formation of somatic embryos was achieved among calli subcultured at 3-4 week interval for at least 4 cycles into either the same medium or with only 100 mg/L coconut water as additive. Various stages of somatic embryo development from the globular, heart-shaped to torpedo stages were observed. Somatic embryos were subjected to maturation using MS-based medium containing 5 to 10 mg/L abscissic acid (ABA). Consequently, complete and efficient plant regeneration was obtained from mature embryos recultured in MS medium with 0.1 mg/L TDZ and 0.5 mg/L gibberellic acid (GA3).