GENETIC-VARIATION IN RADISH (RAPHANUS-SATIVUS L.) GERMPLASM FROM PAKISTAN USING MORPHOLOGICAL TRAITS AND RAPDS

Genetic diversity of 30 radish (Raphanus sativus L.) accessions was in vestigated at the phenotypic level with morphological characters and a t the DNA level using the random amplified polymorphic DNA (RAPD) tech nique. Thirty-six morpho-physiological traits were recorded from seedl ing stage to harvest. The 31 primers used generated 202 RAPD bands, of which 158 (78.2%) were polymorphic. Multivariate procedures were used to classify the germplasm on the basis of phenotypic traits and RAPD fragments. Dendrograms were generated for the Euclidean distance from the morphological data and the Nei's genetic distance from the RAPD ma rkers. Phenotypically, all the accessions were classified into four ma jor groups corresponding to the different forms of cultivated radish. The morphological diversity existing within each of these groups sugge sted that they should be discriminated into the three botanical convar ieties, sativus (large-rooted), caudatus (pod-type) and oleifer (oilse ed-type). Clustering of the accessions did not show any pattern of ass ociation between the morphological characters and the collection sites . Instead, landrace groups were associated with their morphological si milarities and horticultural uses. On the other hand, the intra-specif ic genetic relationships of several accessions based on RAPD analysis were related primarily to their collection sites rather than to their phenotypic affinities. The level of polymorphism exhibited by the vari ous convarieties could be exploited in genetic mapping populations to tag economically important traits. These genotypes also could serve as a useful germplasm source for root, leaf, pod and seed. This prelimin ary study of traditional radish landraces from Pakistan provides usefu l information regarding their horticultural potential.