Production of friable embryogenic callus and regeneration of Ugandan farmer-preferred cassava genotypes
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Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
African Journal of Biotechnology
Abstract
Generation of embryogenic callus is a key step in genetic engineering of many crop species, including
cassava. Protocols for generation of friable embryogenic callus (FEC) have been lacking for Ugandan
cassava genotypes, thereby delaying their genetic engineering for agronomic and other desirable traits.
The objective of this study was to determine conditions suitable for production and regeneration of FEC
in the Ugandan cassava genotypes; Aladu, Bukalasa and Ebwanateraka, and control cultivar 60444.
Immature leaf lobe explants were established on Murashige and Skoog (MS) based media for initiation
of organized embryogenic callus (OES). To produce FEC, resulting OES were established on Gresshoff
and Doy based callus induction media with varying levels of sucrose, maltose, tyrosine, tryptophan,
naphthalene acetic acid (NAA) under light and dark conditions. Subsequently, FEC was subcultured to
MS-based embryo maturation and embryo regeneration media. All genotypes produced OES. All
genotypes produced FEC except Bukalasa. The amino acid tyrosine favoured production of FEC in
Aladu and Ebwanatereka, but not in 60444, while 20 g/L of sucrose trigged production of FEC in Aladu
and 60444, but 40 g/L of sucrose was superior for Ebwanatereka. Media supplemented with 1 ml/L
naphthalene acetic acid NAA facilitated embryo regeneration in Ebwanatereka and 60444, while Aladu
responded better to 5 ml/L NAA. Light, tyrosine and sucrose were essential for FEC production in
Uganda cultivars while NAA was required for regeneration of somatic embryos. Ability to produce FEC
in these genotypes lays a foundation for their improvement through genetic transformation for the
desired and agronomic traits.
Description
Keywords
Cassava (Manihot esculenta Crantz), Somatic embryogenesis, Amino acids, Carbon sources
Citation
Apio, H. B., Alicai, T., Baguma, Y., Mukasa, S. B., Bua, A., & Taylor, N. (2015). Production of friable embryogenic callus and regeneration of Ugandan farmer-preferred cassava genotypes. African Journal of Biotechnology, 14(22), 1854-1864. DOI: 10.5897/AJB2014.14364