Optimizing somatic embryogenesis in Indonesian cassava genotypes: Effects of 2,4-D or Picloram supplementation and explant type.

Modern biotechnological approaches in technology for cassava propagation depend on somatic embryogenic calli (SEC) induction and somatic embryo (SE) regeneration techniques. Consequently, it is essential to develop SEC induction and SE regeneration for cassava genotypes. By assessing the effects of different auxins and explant types, this study aims to develop efficient techniques for inducing cassava SEC and SE. Callus induction medium (CIM) supplemented with 10 mg l-1 2,4-dichlorophenoxyacetic acid (2,4-D) or 12 mg l-1 Picloram was used to cultivate five different types of cassava explants. Subsequently, the induced calli were maintained on CIM until the formation of SEC, which were sub-cultured on the same CIM to promote proliferation and induce SE formation. These SEs subsequently germinated and developed into shoots, which were rooted to produced complete plantlets . These findings indicate that culturing-induced axillary bud explants on CIM supplemented with 12 mg l-1 Picloram is an effective method for inducing SEC in cassava. Histological analyses and cryogenic electron microscopy observations confirmed the development of SECs and SEs on CIM. Our finding, in which up to 202.3 SEs were regenerated from 10 induced axillary bud explants on CIM supplemented with 12 mg l-1 Picloram in the Menti genotype, highlights the effects of auxin and explant types on SEC and SE induction. Although further research is required, the methods developed in this study will contribute to the successful breeding and micropropagation of cassava.