Report-DS24-3019 (1).zip

<i>Sorghum bicolo</i>r [L.] Moench is the fifth-most important grain crop worldwide. Evaluating its genetic diversity is crucial in making the best choices and conducting effective breeding operations. This study evaluates the genetic diversity and population structure of 74 breeding lines and released varieties from South Africa and Zimbabwe. Sorghum is becoming an important crop in response to climate change but sources of genetic diversity need to be explored to be used in other breeding programs for example breeding for drought and disease resistance. In this study, 27,870 SNPs were utilized to analyze 74 sorghum genotypes. Only 23.5% of the SNPs in this study fulfilled the selection criteria and exhibited polymorphism across the 74 genotypes. The PIC values obtained from the DArT SNP markers ranged from 0.1 to 0.27 on average, indicating moderate genetic diversity. The genotypes displayed significant genetic diversity, with an average genetic diversity of 0.3. Molecular variance analysis revealed low variation within individuals but substantial variation among individual genotypes. The genotypes revealed low levels of differentiation across individuals within the same subpopulation, but significant differences (p&lt;0.001). Chromosomes with the highest SNP density (&gt; 163 SNPs/10 megabase pairs (Mb)) were Chr1, Chr2, Chr3, Chr4, Chr6, and Chr9. The average SNP density for chromosomes Chr5 and Chr8 was less than 91 SNPs per 10 Mb. The genotypes were divided into nine groups using cluster analysis of the 74 genotypes produced using the unweighted pair group method with the arithmetic mean (UPGMA) approach. Populations 1-9 represented 10.8% (5.4% Zimbabwean and 5.4% South African), 8.1% (80% Zimbabwean and 20% South African), 24.3% (88.9% Zimbabwean and 11.1% South African), 8.1% (83.3% Zimbabwean and 16.7% South African), 6.8% all South Africa, 14.9% (81.8% Zimbabwean and 18.2% South African), 12.2% (55.6% Zimbabwean and 44.4% South African), 6.8% (20% Zimbabwean and 80% South African), and 8% (50% Zimbabwean and 50% South African) of the entire population, respectively. Low variation within individuals suggests the need to further widen the genetic base of the crop. The study identified five genotypes of South African origin that can be used as sources of genetic diversity in future breeding programs.