<i>In Vitro</i> Propagation of Vanilla in Rwanda

Abstract

Vanilla (Vanilla planifolia) is an herbaceous, perennial, climbing orchid belonging to the family Orchidaceae and order Orchidales. Vanilla is a high value export crop and it is cultivated for its beans that contain sweet scent, aroma and pleasant flavor, mainly due to the presence of vanillin. It is used as flavoring substance in several items such as chocolates, ice-creams, yoghurts, soft drinks, liquors, candies, baked foods, cakes, and biscuits. It is also used in scenting tobacco, perfumery and pharmaceuticals. Vanilla is the second most expensive spice after saffron and its demand worldwide is enormous. It is often referred to as “green gold” or “princess of spices”. This crop can be profitably grown in some parts of Rwanda and currently it is being grown by a small number of farmers in Eastern Province. However, lack of adequate planting materials remains the major bottleneck in exploiting its potential in Rwanda. The objective of the study was to evaluate the effect of growth regulators on in vitro regeneration of plantlets from vanilla nodal explants. Nodal explants harvested from screen house grown vanilla vines were sterilized and cultured on Murashige and Skoog medium supplemented with 100 mg/l inositol. 20 μM/l argine, 3% sucrose and gelled with 0.3 % Phytagel. The cultures were incubated in a growth room maintained at 26º C and 16 hours photoperiod. The Kruskal-Wallis test showed that there were highly (p=0.001) significant differences among the two cytokinin levels for microshoot elongation in vanilla. The two cytokinins tested induced bud break to different degrees. Among the different growth regulators evaluated, BAP (benzylaminopurine) at 2.5 μM/l gave the highest mean shoot number at 1.21±0.80 and the highest shoot length with 3.34±1.61cm. The regenerated plantlets were successfully transferred to soil and acclimatized in the greenhouse. The protocol developed in this study is a significant advance on those previously reported for vanilla due to its efficiency and reproducibility and is a major step towards large scale vanilla production in Rwanda.

Keywords: In vitro propagation, Vanilla planifolia

Rwanda Journal, Volume 24 Series E 2011