Study on the regeneration of sausage tree (Kigelia africana) by tissue culture

Abstract

This study investigated the regeneration of sausage tree (Kigelia africana) using tissue culture techniques, focusing on callus induction, shoot regeneration from seeds, and root induction from shoot explants. Seeds were cultured on solid MS medium supplemented with various concentrations of BA (0.5, 1, 2, 3, and 5 mg L⁻¹) for 10 weeks. Callus formation was observed at all BA concentrations, with the largest mean callus volume (5214.17 mm³) and highest induction rate (80%) achieved at 5 mg L⁻¹. Shoot regeneration occurred across all BA treatments, with the highest number of shoots (45 shoots; 86.54%) obtained on medium containing 1 mg L⁻¹ BA. Root induction was studied using shoot segments derived from seed-induced shoots cultured on MS medium supplemented with IAA, NAA, or IBA for 4 weeks. IAA at 0.5 mg L⁻¹ induced roots in 33.33% of explants with an average root length of 6.68 mm. NAA at 2 mg L⁻¹ promoted the highest root induction (70.83%), though roots were shorter, while 1 mg L⁻¹ NAA produced fewer roots but with greater length (7.00 mm). IBA at 3 mg L⁻¹ induced rooting in 33.33% of explants with an average root length of 3.78 mm and also stimulated callus formation, with the largest callus volume observed at 2 mg L⁻¹. These results demonstrate that BA is effective for callus and shoot induction, whereas IAA, NAA, and IBA promote root formation, with distinct responses at different concentrations. The optimized protocols provide a foundation for in vitro propagation, mass multiplication, and conservation of K. africana, with potential applications in biotechnology and secondary metabolite production.