Abstract

S6-23

DNA Analysis for Characterisation of Genetic Resources  and Identification of Duplicates in Cassava

Pillai S.V., P. Harisankar, G.O. Sumarani and S. Sundaresan

DNA analysis using Random Amplified Polymorphic DNA (RAPD) method was used to characterise a cassava germplasm maintained at Central Tuber Crops Research Institute, Thiruvananthapuram, India, with special emphasis to identify duplicates.  Characterisation of the germplasm using eleven morphological characters revealed 138 duplicate sets, out of which 67 sets were also found to be duplicates at isozyme level.  These were further analysed for DNA polymorphism using the RAPD method.  The number of DNA bands based on one primer, varied from 2 to 9 in an accession and 40 to 45 bands were evident in the group.  The data were analysed for base pair and genetic distance using the Software ‘AAB ID Advanced’.  Twenty eight sets were found to be duplicates based on nine primers used.  Most of the duplicates came  from related gene pool.  This information, together with other data, will be useful to eliminate unwanted accessions and to identify core collection from the germplasm.  Some of the duplicate sets with minor variations in DNA were found to vary either in specific morphological or economic characters.  These sets will be useful for the identification of molecular markers for specific characters.  This is important in a highly heterozygous crop like cassava, where production of Near Isogenic Lines (NIL) for gene isolation is difficult.