Comparing the Effect of Plant Growth Regulators on Callus and Somatic Embryogenesis Induction in Four Elite Theobroma cacao L. Genotypes

Abstract

<jats:p>The effect of plant growth regulators on callus and somatic embryogenesis induction in four Cocoa (<jats:italic>Theobroma cacao</jats:italic>) genotypes was studied. Flower explants were harvested early in the morning and cultured on Driver and Kuniyuki Walnut (DKW) medium supplemented with 1 mg·L<jats:sup>−1</jats:sup> of five auxins type (2,4 dichlorophenoxyacetic acid (2,4-D), 3,4 dichlorophenoxyacetic acid (3,4-D), 2,4,5 trichlorophenoxyacetic acid (2,4,5-T), 4-amino-3,5,6-trichloropicolinic acid (picloram), and 3,6-dichloro-2-methoxybenzoic acid (dicamba) in combination with 0.25 or 0.5 mg·L<jats:sup>−1</jats:sup> of two cytokinins type (benzylaminopurine (BAP) and 6-furfurylaminopurine [kinetin (Kin)] in a factorial experiment. The plant growth regulators 2,4-D and 2,4,5-T proved to have a broad spectrum action on somatic embryogenesis induction compared with 3,4-D or picloram. There were no significant differences between the two concentrations of cytokinins. However, Kin was found to be more effective in promoting somatic embryogenesis than BAP. Combining 1 mg·L<jats:sup>−1</jats:sup> 2,4,5-T or 2,4-D with 0.25 mg·L<jats:sup>−1</jats:sup> Kin had a broad spectrum action on embryogenesis induction. On the other hand, combining mg·L<jats:sup>−1</jats:sup> picloram with 0.5 mg·L<jats:sup>−1</jats:sup> Kin or 1 mg·L<jats:sup>−1</jats:sup> 3,4-D with 0.25 mg·L<jats:sup>−1</jats:sup> Kin was only able to induce somatic embryogenesis in a few of the genotypes evaluated. The protocol developed during the current study differs from earleir works as the callus (derived from explants cultured on DKW media) was taken directly to embryo development media as opposed to earlier works in which the callus was taken through a secondary media before being transferred to an embryo development media.</jats:p>

Comparison of systems combining auxins with thidiazuron or kinetin supplemented with polyvinylpirrolidone during embryogenic callus induction in three <i>Theobroma cacao</i> L. genotypes

“…Indeed, both combinations have favored embryogenesis from the petals. These results are in agreement with those of Kouassi et al (2017a) who used the auxin/Kin system and Issali et al (2008) who used the auxin/TDZ system. However, other authors (Li et al, 1998;Tan and Furtek, 2003) obtained a better embryogenic response with staminodes using auxin/TDZ system.…”

“…Previous studies as well as this one reported that petals were more embryogenic than staminodes. This is consistent with the C1 genotype (Kouassi et al, 2017a). The best response observed in the petals indicates that both auxins/cytokinins systems, namely auxin/Kin and auxin/TDZ, did not induce embryogenesis differently.…”

“…The use of 2,4-D and TDZ during the induction phase of somatic embryogenesis is referred to as the "2,4-D / TDZ system" in this paper. Our recent studies have shown the positive influence of the system "auxin/Kin" on induction of embryogenic calli that used combinations of 2,4-D/Kin and 2,4,5-T/Kin (Kouassi et al, 2017a). In addition, PVP tested in the 2,4-D/TDZ system improved the induction of embryogenic calli (Kouassi et al, 2017b).…”

Cacao biotechnology: current status and future prospects

“…Other beneficial modifications to SE media have been reported recently by Kouassi et al . () and Modeste et al . ().…”

Enhancement of Somatic Embryogenesis by Mature and Immature Seeds in Wheat (Triticum aestivum L.)

“…Plant growth regulators and optimization of their proper dosages are also very important for success in in vitro culture (Kouassi et al, 2017;Bhattacharjee and Islam, 2014;Morshed et al, 2014). The somatic and gametic embryogenesis on major cereal crops report that regeneration capability depends on genotype (Ksia et al, 2008;Islam et al, 2001).…”