<i>In vitro</i> propagation and microtuberization of yam ( <i>Dioscorea species</i> ) 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.