In vitro propagation and microtuberization of yam (Dioscorea species) Hatiye landrace

Yam (Dioscorea species) has long been cultivated in Ethiopia, where farmers rely on conventional propagation using whole tuber seeds. This leads to a scarcity of clean tuber seeds, which limits production. This study aimed to optimize in vitro propagation and micro-tuberization protocols for the ‘Hatiye’ landrace, which focused on in vitro propagation, including shoot initiation, multiplication, and rooting, and micro-tuberization using MS medium supplemented with different concentrations of plant growth regulators. Experiments were arranged in a completely randomized design with three replications, using nodal segments as explants. For shoot initiation, four levels of α-naphthalene acetic acid (NAA) were combined with four levels of 6-benzylaminopurine (BAP). The highest shoot initiation (99.9%) and shortest initiation period (6.67 days) were obtained with 0.25 mg/L NAA and 1.0 mg/L BAP. During multiplication, seven MS medium treatments with different BAP levels were tested, while rooting was assessed with six NAA concentrations. The highest rooting percentage (99.9%), root number (9.67), and root length (9.5 cm) were recorded at 2 mg/L NAA. For microtuberization, MS medium with two BAP levels (0 and 2 mg/L) combined with five sucrose concentrations was tested under 10/14 light/dark hours. The highest number of microtubers (2.5) and longest microtuber lengths (1.67 mm and 1.23 mm) were achieved with 2 mg/L BAP and 60 g/L sucrose. This study provides a reliable protocol for in vitro propagation and micro-tuberization of the Hatiye yam landrace, addressing the shortage of clean tuber seeds and supporting yam production in Ethiopia.