Abstract:
The sustenance and progress of any breeding program and conservation of its germplasm is hinged on the ability to estimate the degree of genetic diversity in a given gene pool for maintaining crop production. Therefore, data on the genetic diversity and relationships among plant genotypes is vital to identifying the complexity of the gene pool, to ascertain breaches in genotype collections in order to develop effective conservation and management strategies. This study was conducted to characterize, evaluate and determine the phenotypic as well as genetic relatedness of cotton genotypes utilizing both morphological and molecular markers. A field trial was carried out at CSIR-SARI Station, Nyankpala, Ghana to evaluate 90 genotypes of cotton in an Augmented Randomised Incomplete Block Design (ARIBD). The results revealed moderate variation among the genotypes. Lint colour and stigma type showed variation among the qualitative traits. Seed cotton yield exhibited supreme variance among the quantitative traits. Pearson’s correlation coefficient revealed high and positive significant correlations between traits that contribute to seed cotton yield. Cluster analysis was largely influenced by yield and yield related traits and grouped of the genotypes into three distinctive clusters. Twenty SSR markers selected produced a total of 36 alleles with 14 (70%) of the markers polymorphic. The average number of polymorphic alleles per primer was 0.37. Cluster analysis of molecular data produced five clusters. The accessions SCn17/07041, SCn17/07034 and SCn17/07062 exhibited 100% similarity. The results of combined morphological and molecular analysis matched the results observed for the morphological markers but were divergent with that of the molecular markers. High yielding genotypes Scn17/07060, Scn17/07048, Scn17/07039, Scn17/07019, Scn17/07026, Scn17/070649 and Scn17/07016 as revealed in the study should be used as parents in crosses with locally adapted but low yielding cotton varieties (CSIR-SARI released varieties SARCOT 1 and SARCOT 5 and farmer variety FK 37) so as to boost cotton production in the country. These high yielding genotypes should also be multiplied and evaluated multilocationally for adaptability.