Abstract

The genetic and morphological diversity of soybean germplasms was studied using random amplified polymorphic DNA (RAPD) markers and morphological traits such as plant height, height of cotyledon leaves, basal leaf length, basal leaf width, basal leaf area, terminal leaflets number, terminal leaflet length, terminal leaflet width, terminal leaflet area and basal leaf petiole length. A total of 30 germplasms were investigated. The number of amplification products obtained ranged between 6 and 9. An average of five bands was obtained per primer set. The RAPD analysis of the 30 soybean germplasms revealed a total of 23 bands, amplified by 14 different oligonucleotide primers. Sixteen of these bands were highly polymorphic with percentage polymorphism at 70%, indicating the germplasms investigated had a high level of genetic diversity. The consensus tree generated from the genetic diversity analysis placed the soybean germplasms into five groups at an agglomerate coefficient of 0.6 (similarity level). Similarly, cluster analysis from the morphological characterisation revealed 5 clades with an average distance between clusters of 0.75. There was a significant lack of correlation between the RAPD markers and the morphological traits evaluated. Although, both analyses grouped the soybean genotypes into 5 clades, the composition of the individual clusters were very variable and divergent with the correlation between the largest clusters in the molecular and morphological characterisation at only 35-42%.

Key words: Soybean, germplasm, random amplified polymorphic DNA (RAPD), genetic diversity, morphological variability, polymorphism.