Zygotic embryo in vitro culture of Cocos nucifera L. (sv. East African Tall variety) in the coastal lowlands of Kenya

Abstract

In vitro embryo culture of Cocos nucifera L. was carried out with the aim of determining whether it can be applied as an alternative coconut propagation tool to address the lack of planting materials in Kenya. Zygotic embryos excised from mature healthy pyrenes of high yielding Cocos nucifera L. (sv. East African Tall, a coconut variety from Kenya) were cultured using Murashige and Skoog (MS) culture medium supplemented with plant growth regulators (PGRs) namely 6-benzyl aminopurine (BAP) (0.5 mg/l), naphthalene acetic acid (NAA) (0.5 mg/l), 2,4 dichlorophenoxyacetic acid (2,4-D) (1.7 mg/l) and indole butyric acid (IBA) (1.7 mg/l). Germination of 84 and 27% embryos were recorded in liquid and semi-solid MS medium, respectively. Embryo cultured in liquid medium and incubated in darkness during the initial four weeks resulted in a germination percentage of 80% while incubation in light resulted in only 30% germination. MS medium was also supplemented with 100, 25, 15 and 0% (v/v) coconut water (CW). Embryo germination was 60% in medium supplemented with 15% (v/v) coconut water although 0% (v/v) gave the highest germination rate at 67%. Medium supplementation by 1.7 mg/l 2,4-D PGR resulted in germination of 30% when plant growth regulator was co-autoclaved and 84% when plant growth regulator was sterilized by microfiltration. The results presented in this study indicate that in vitro micropropagation of the Kenyan variety of Cocos nucifera L. is a feasible alternative. Keywords : Cocos nucifera L., in vitro embryo culture, east African tall (EAT) Kenyan variety, zygotic embryo African Journal of Biotechnology Vol. 12(22), pp. 3435-3440