Proc. of
Effect of IBA, Kinetin, and Benzylaminopurine
on the Germination, Shoot Development, and Root Formation in Avocado Embryos
Cultivated in vitro
Hector Gonzalez-Rosas and Beatriz E. Llano-Agudelo
Centro de Fruticultura, Colegio
de Postgraduados, Chapingo, Edo.
Samuel Salazar-García
Campo Experimental
Abstract. Genetic improvement programs for finding avocado
genotypes that are resistant or tolerant to adverse conditions of cultivation
usually take several years, and on occasion, the expected results are not
obtained. The in vitro cultivation of embryos is an alternative that
allows us to select genotypes with outstanding characteristics in a shorter
period of time. The objective of this work was to establish the hormonal
requirements for the rapid obtainment of plantlets from mature embryos of
Creole avocados through in vitro cultivation in a chemically-defined
medium.
Mature embryos from creole
avocado seeds (Persea americana Mill.) of Mexican race were cultured in
vitro on Murashige and Skoog
(MS) medium complemented with 2.0 mg/L glycine, 100
mg/L myoinositol, 5 mg/L pyridoxine-HCI, 1.0 mg/L thiamine-HCI,
5.0 mg/L nicotinic acid, 30.0 g/L sucrose, and 7.0 g/L bacto
agar. The pH of MS medium was adjusted to 5.7 with 0.1 N of NaOH
or HCI. The embryos were excised with a small piece of cotyledon attached and
inoculated with five levels of indole-3-butyric acid (IBA) alone or in
combination with five levels of kinetin (K) or benzylaminopurine
(BA). The levels used were: 0.01, 0.1, 0.3, 1.0, and 3.0 mg/L. The explants
were cultured at 25±2C in darkness for 21 days and subsequently under
continuous light (3000 lux cool white fluorescent
irradiance). Thirty-five days after inoculation, the percentage of germination
and the number of shoots and roots increased for the explants were placed in a
basic medium with 0.3 mg/L of IBA and 1.0 mg/L of K added; bud growth was better
in the treatment with 1.0 mg/L of K and 1.0 mg/L of IBA. The length of the root
was stimulated with the combinations of 0.01 and 0.3 mg/L of K with 0.3 and 1.0
mg/L of IBA. Negative effects on shoot growth were observed when benzylaminopurine was added.