Germinability of In-Vitro Conserved Dioscorea Microtubers in Different Storage Conditions

Dioscorea is a traditional tuber crop species. Sri Lanka has eleven local and one introduced Dioscorea species. Two hundred and five Dioscorea accessions have been conserved in in-vitro and in-vivo conditions at the Plant Genetic Resources Center (PGRC), Sri Lanka as a national mandatory duty. In-vitro conservation of Dioscorea needs frequent sub culturing hence conservation cost is very high. Conservation of Dioscorea as microtubers is a cost effective alternative method. Therefore, this research was conducted to identify the optimum microtuber size and storage temperature to develop a method for microtuber conservation. Four D. alata accessions; Raja ala, Angili ala, Kiriwel ala, Peni ala and one D. bulbifera accession; Bakamunu ala were selected for this research. In-vitro initiated microtubers having four different microtuber diameter categories of five selected accessions were tested under three storage temperature levels. The experiment was laid-out as a completely randomized design with five replicates. After one year of storage period germination was induced and germinability was recorded. ANOVA was performed to analyze the data. At 25 °C storage condition microtuber categories of diameter > 5 mm of all selected accessions couldn’t be conserved for more than 4.5 months. The microtubers with the diameter < 5 mm at any tested temperatures had zero germination. All selected accessions having microtuber diameter >5 mm can be conserved at 1 °C or 4 °C temperatures for one year with a very low germination (3.68%). Further studies have to be conducted to improve the germinability of conserved microtubers of Dioscorea spp.