Effect of Plant Hormones for Micro Propagation on Improved and Landrace Yam Varieties (<i>Dioscorea species</i>) Via Nodal Culture

Abstract

Yam (<i>Dioscorea species</i>) is a monocotyledonous tuber forming tropical vine which belongs to the order <i>Liliflorae</i>, family <i>Dioscoreaceae</i>, and genus <i>Dioscorea.</i> Conventional propagation of yam (Dioscorea spp.) is limited due to low propagation rates and highly infected by pests. However, <i>In vitro</i> clonal propagation is the best alternative to mass multiplication over conventional propagation. Moreover, shoot multiplication and rooting induction experiments were incubated on hormone free MS medium within 30 g/l sugar and 7 g/l agar. For shoot multiplication the initiated shoots of both landraces were cultured on MS media supplemented with 0, 1, 2, 3, 4 and 5 mg/l benzyl amino purine (BAP). For root induction, shoot lets were cultured on MS media supplemented with 0, 1, 2, 3, 4, 5 and 6 mg/l indol-3-butyric acid (IBA). Finally, for acclimatization, <i>in vitro</i> multiplied plantlets were transferred to greenhouse for hardening off. The results showed that the interaction effects of both landraces with BAP and IBA concentrations was significantly influenced <i>in vitro</i> yam shoot multiplication and rooting induction respectively. The maximum shoot number (7.23±0.21) with a maximum shoot length 7.68±0.24cm and 6.79±0.09 shoot number with 7.47±0.47 cm were obtained on MS media supplemented with 3 mg/l BAP for 11/02 and Koffea cultivars respectively. The maximum root number 10.03±0.49 and root length 10.76±0.16 cm and 10.58±0.26 root number with 10.42±0.32 cm were recorded on MS media with 3 mg/l IBA for Koffea and 11/02 cultivar respectively. <i>In vitro</i> raised plantlets were acclimatized and recorded 86% and 90% of survival rate in Koffea and 11/02, respectively, on soil medium with combination ratio of 2:1:1 top soil, sand soil and compost, respectively.