1. ABSTRACT
Yam (Dioscorea spp.) is an important vegetable crop in tropical countries of Africa, the
Caribbean, South America, and South East Asia. Tubers which contain 2-3 times more
protein than sweet potato, cassava, which is the major staple food for about 200 million
people in West Africa. There is need to increase production from limited available resources.
The objectives of the research was to identify the effective colchicine concentrations, time
duration and plant regeneration media for mutation treated Dioscorea alata plantlets in order
to modify plant morphological characters. The effects of 0.1%, 0.15%, 0.2% and 0.25%
aqueous solution of colchicine in 24hr, 48hr and 72hr treatments with two hormone level,
survival rate and morphological features of Dioscorea alata were investigated. Inter nodes
were treated with colchicine and their performances were monitored after two month.
Complete Randomized Design (CRD) with ten replicate was used for study.Statistcal analysis
was performed with Duncan’s multiple range test using SAS software (version 9.1.3).Result
showed that survival of inter-nodes was lower in 0.25%, 72h treatment. However, colchicine
treated nodes had potential to survive in 0.1%, 0.15%, 0.2% in 24hr and 48hr treatments.
Morphological variation in shoots number, shoot length and root number can be seen in
0.2%, 24hr colchicine treatment. Between two hormone level media, MS media with 0.5mgL-
1 NAA and 1 mgL-1 BAP (DM1) can be used as regeneration medium for colchicine treated
shoots. Colchicine has also increased the size of stomata density and structure in Dioscorea
alata. Our results suggest that colchicine has created morphological changes in yam which
may be of agronomic importance in the production of the crop.
Key words: Colchicine, Dioscorea alata, DM1, Morphological Variations, Regeneration
Medium,