Raja ala and Kakulu ala: Two New Improved Varieties of Greater Yam

Abstract

Yams are being cultivated by farmers since ancient times in Sri Lanka. This crop produces high edible  energy per hectare, contains more protein than most of the other root and tuber crops and serves as  a supplementary food with medicinal properties. Evidence indicated that more than eight edible  species of Dioscorea are present in Sri Lanka, of which greater yam (D. alata) and lesser yam (D.esculenta) are widely cultivated. Some of these species, though edible, are not cultivated mainly due  to the low productivity and deep penetrating nature of their tubers. However, yams could be popularized,  with the identification of high yielding shallow types, which have satisfactory culinary qualities as they  need very little attention on agronomic practices. More than 90 accessions of Dioscorea germplasm  were collected and maintained at the Horticultural Crops Research and Development Institute (HORDI)  fields. Characterization using 25 morphological traits was carried out to identify the species of these  accessions. Studies showed that due to the vegetative nature of these crops, the same variety had  been known by different names at different locations and different clones had been erroneously  called by the same name in different locations and had caused duplications. To avoid duplications,  characterization of 25 morphological traits and cataloguing of this collection was done along with theevaluation for their yield potential, quality and other desirable agronomic characters. Thus 30 distinct  Dioscorea alata genotypes were identified. Out of these, selections were made and two improved D.  alata varieties, Raja ala and Kakulu ala having high yield, good culinary qualities and high marketablevalue were released in 2007.Key words: Dioscorea alata, Dioscorea esculenta, Characterization