A comparative study of water stress tolerance between Dioscorea Rutondata and Dioscorea Alata Yam Species

Abstract

This study focused on comparing the water stress tolerance of two yam species of D. rutondata the white and D. alata using tissue culture techniques with the aim of screening for a more drought tolerant variety. Yam is important for food security as the mainstay for at least 60 million people and income generation. Given the vulnerability of yams to drought, swamps and wetlands would be ideal for sustained production of this crop yet these two habitats are disappearing drastically due to human activities, there is therefore a need to identify drought tolerant yam varieties which can be used to improve the drought tolerance traits of other varieties if the yam industry is to be sustained amidst the worrying wave of climatic. The study which was conducted at Makerere University, department of microbiology plant sciences and biotechnology in the tissue culture lab involved three experimental groups for each species subjected to varying agar concentrations that is 7g, 11g and 15g with three replicates in each. Generally, all the species were affected in their growth by high osmotic stress induced by increasing agar concentrations.

At concentration 7g and 11g there was no significant difference in the survival and behavior of the species, however at agar concentration 15g, the growth behavior as well survival of species were significantly different with D. rutondata performing better than D. alata. The findings of this study clearly indicate that at optimum growth conditions without stress, D alata performs better than D rutondata in all dimensions while in very highly stressed conditions D. rutondata performs significantly better than D. alata.