GENETIC DIVERGENCE IN TETRAPLOID POTATOES (SOLANUM TUBEROSUM SUBSP. TUBEROSUM) AS REVEALED BY RAPD VIS-À-VIS MORPHOLOGICAL MARKERS

Abstract

Genotypic divergence within a group of 31 genotypes, preferentially used as parents for potato breeding in India, has been estimated from both random amplified polymorphic DNA (RAPD) and morphological data. RAPD data revealed a broader genetic divergence (similarity values 0.52-0.80, ca 0.65) than that of morphological data (0.60-0.98, ca 0.86). A weak positive correlation between the similarity values derived from RAPD and morphological data was observed. Both the types of analyses separated tuberosum from andigena genotypes, and indicated andigena accessions as the most distantly related genotypes within the group thus suggesting better value as parents. However, no significant correlation between the similarity matrices obtained from RAPD and morphological data was observed as indicated by a very low (0.3) matrix correlation value. It may be concluded that divergence analysis using RAPD markers would be a cheaper and feasible technique for parent selection in tetraploid potatoes. Apparently no such comparison has so far been made for the divergence data derived from RAPD markers with that of morphological diversity in potato. Average pair-wise dissimilarity of any particular genotype, calculated on the basis of all possible combinations in the group, may give an idea about its usefulness in breeding programme.