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Response of African palm hybrid iniap-tenera grown in vitro as affected by explant type and naphtaleneacetic acid levels

Abstract:

Bud rot (BR) has affected and devastated more than 22 thousand hectares of oil palm (Elaeis guineensis Jacq.) in Esmeraldas province, Ecuador. It has been noted certain tolerance of the hybrid INIAP-Tenera in areas of high incidence of BR. The objective of this study was to achieve the establishment of in vitro clonal propagation of the commercial hybrid, supported by the fact that productivity of elite clones can be higher than that of plants grown from seeds. Leaf primordia, male inflorescences and zygotic embryos were used as explants and they were submitted to the usual techniques for disinfection and disinfestation of explants. Tissues were cut into sections 5 to 12 mm and plated on MS culture media supplemented with 0, 50, 100 and 200 mg·L-1 naphthaleneacetic acid (NAA), sucrose (30 g·L-1) and activated carbon (3.0 g·L-1), and maintained in dark conditions at 28±2 °C. Forty five days after tissues were cultured, the internal contamination level was between 0 and 29 %, mainly due to the presence of bacteria. There were different degrees of oxidation (none, medium, and medium-high), depending on the explant type and ANA concentration. The percentage of callogenesis was superior when using leaf primordia (42.02 %), and 100 mg·L-1 ANA (47.64 %), while rhizogenesis occurred only in explants of zygotic embryos (14.01 %). The successful establishment of the hybrid explants and the induction of morphogenetic responses are described. They show, that the best explants were leaf primordia and zygotic embryos with important percentages of callogenesis when 100 mg·L-1 of ANA were added to the culture medium.