Exploring the African cassava (Manihot esculenta Crantz) germplasm for somatic embryogenic competence

Somatic-embryogenic competence of eleven cassava genotypes was determined in induction media containing 8 and 12 mg/l of the auxin picloram, using axillary meristems and leaf lobes as explants. There were significant differences (p<0.01) among the cassava genotypes for ability to form somatic embryos. Proembryo formation took between 27 to 35 days and ranged between 34.5% for TME 596 and 0% for SL80/40. Embryo formation at the two picloram concentrations were not significantly different. Pro-embryos formed by two genotypes viz I96/1439 and I95/0528 did not survive beyond the globular developmental stage. Generally the level of proembryo formation was not adequate as an indicator of embryogenic competence. Development to torpedo stage took between 55 to 65 days. Higher success was achieved with leaf lobes (21.7%) than axillary meristem (13.8%). There was a significant (p<0.01) genotype x explant interaction, indicating that ability of the cassava genotypes to undergo somatic embryogenesis was influenced by the explant. Seven out of the eleven (63.63%) cassava genotypes studied showed capability to undergo somatic embryogenesis.