Comparison of morphological and molecular grouping of some exotic safflower (Carthamus tinctoriousL.) accessions introduced into Kenya

Abstract

Safflower is a drought tolerant annual oil crop. Safflower is a worldwide valued for its high quality oil and as a herb, in the treatment of many human diseases. Rich safflower genetic resources are found in the center of origin (the Mediterranean and the main production areas like India, USA, China and Mexico). As safflower moved to other regions, accessions from those areas would be expected to share at least some common genetic structure. Globally, there has been extensive exchange of germplasm. Hence estimation of genetic diversity in a plant species can assist in the identification of possible sources of genes, which can be utilized in cultivar improvement. Characterization of 36 exotic safflower accessions based on morphological and RAPD markers has been reported. But combined clustering of the two marker systems had not been reported. The objective of this study was to group safflower accessions using combined morphological and RAPD data. Means over sites and years were standardized and the data used to generate a similarity matrix (derived from the Euclidian distance), which was correlated with the similarity matrix from the RAPD data using the MXCOMP matrix comparison programme. A dendrogram derived from combined clustering revealed seven distinct clusters with most accessions grouping in cluster six (15). PI 198009 and Girna were genetically the most distinct accessions. Though both originated from India, they fell in different groups (group 1 and group 7 respectively. Three distinct genetic diversity pools of 1 accession, 34 accessions and 1 accession were identified at a similarity coefficient of 3.0. The bigger group of 34 accessions was found to have five sub-groups. The absence of a relationship between country of origin and clustering of the different accessions suggests that selection of parents in safflower breeding should not be based on country of origin because this may not be an accurate indicator of genetic diversity.