Genetic diversity and population structure of Leucaena leucocephala (Lam.) de Wit genotypes using molecular and morphological attributes

For the estimation of genetic diversity and population structure, 23 accessions of Leucaena leucocephala were characterized using morphological and molecular markers. A medium to high degree of genetic variability was calculated among these accessions based on eight quantitative traits. Furthermore, a cluster analysis based on morphological characteristics grouped the 23 Leucaena accessions into five groups based on their similarities. Furthermore, the principal component analysis revealed that eight quantitative traits contributed for 82.57% of the total variability. Eleven simple sequence repeats (SSR) markers showed a high degree of polymorphism among the 23 L. leucocephala accessions. The polymorphic information contents (PIC) for these 11 markers were estimated and revealed that SSR723 had higher PIC value (0.90). Also, the dendrogram generated based on 11 markers distinctively demarcated most of the L. leucocephala accessions into different clusters indicating its vast genetic diversity in the population. A population structure study of these 23 L. leucocephala accessions showed the existence of two gene pools. Also, analysis of molecular variance showed that there was 13% variability between populations, while there was 87% variability within the population. The first and second coordinates of principal coordinate analysis unconditionally distributed these accessions into four coordinates based on their similarity. Overall, the high degree of genetic variability described by morphological and molecular markers in L. leucocephala can be used as a basic tool for assessing genetic diversity and linkage mapping in Leucaena genetic improvement programs.