CHARACTERIZATION OF FINGER MILLET (Eleusine Coracana L. Gaertn.) GENOTYPES USING MORPHOLOGICAL TRAITS AND SIMPLE SEQUENCE REPEAT MARKERS

Abstract

Finger millet is a crop with largely unexplored and unexplained potentially valuable genetic variability. The knowledge and understanding of the extent of genetic variation of finger millet germplasm is important for conservation and improvement. The study aimed at estimating the genetic divergence of finger millet genotypes using morphological and simple sequence repeat (SSR) markers. Fourteen finger millet genotypes were evaluated under field conditions in 3 sites replicated three times, for 37 morphological traits recorded by the International Board for Plant Genetic Resources (IBPGR) as the minimum that ideally should be used in the identification of any accession and in the laboratory using 12 SSR markers. The SSR markers had several advantages over other molecular markers: microsatellites allowed the identification of many alleles at a single locus, they were evenly distributed all over the genomes, they were co-dominant, little DNA was required and the analysis c be semi-automated and performed without the need of radioactivity .Findings from this study showed that The interaction between genotypes and site were significant (p≤0.05) for finger length and leaf blade density of hairs on upper side and (p≤0.001) for productive tillers, days to 50% flowering, days to physiological maturity, number of tillers, a thousand grain weight (g), grain yield per plant (g) and yield in Kg per hectare. Also the principal component analysis (PCA) indicated that the morphological traits principal component (PC) 1, 2 and 3 accounted for 16.98%, 14.17% and 12.45% of total variance, respectively, that is, 43.6% of the total variation. The dendrogram based on UPGMA cluster analysis revealed that SSR and morphological data indicated the existence of high divergence among the accessions. The cophenetic matrices obtained with morphological, SSR and combined data marker types were high, 0.81, 0.90 and 0.78, respectively. The consensus fork index (CIc) obtained from morphological and SSR data was 60% identical (CIc= 0.60). Both morphological descriptors and SSR markers were able to group the genotypes into distinct clusters. At certain stages, the morphological traits used were able to distinguish between cultivars and the molecular markers complemented the data obtained to detect genetic differences and were able to distinguish them into distinct genotypes with some located in different clusters. These results support the idea of combining both methods, to obtain a more accurate idea of the genotypes under study. I recommend that the findings of this research be used in the collection, conservation and documentation of finger millet genotypes and that this information is used for crop improvement and exploitation of the crop genotype in order to raise the standards of living of the consumers of the crop.