Greener Journal of Plant Breeding and Crop Science Vol. 1 (1), pp. 016-024, September 2013.
ISSN: 2354-2292 © 2013 Greener Journals
Manuscript Number: 240913858
Assessment of Genetic Diversity and Structure of Sudanese Sorghum Accessions using Simple Sequence Repeat (SSRs) Markers
1Yasir A. Gamar*, 2Dan Kiambi, 3Mercy Kairichi,4Martina Kyallo and 1Mohamed H. Elgada
1Agricultural Research Corporation, ARC, Wad-Medani, Sudan, P. O. Box 126.
2African Biodiversity Conservation and Innovations Center (ABCIC), Nairobi, Kenya.
3University of Nairobi (UoN), Kenya.
4Bioscience Eastern and Central Africa (BecA-Hub), Nairobi, Kenya.
*Corresponding Author’s Email: gamarotta @ yahoo.com, Tel: +2499-128-47869
95 sorghum accessions (1,425 individuals) sampled represented most of crop- cultivated areas in Sudan. The genetic diversity and population structure was assessed using a panel of 39 SSRs marker, which covered the sorghum genome. Genotypic data was generated using the ABI 3730 genetic analyzer. The alleles were called and sized using GeneMapper software version 3.7. The molecular data analysis software’s PowerMarker v3.25, DARwin 5, and GenAIEx 6.5x were used to calculate the different diversity indices within and between populations. A total of 332 alleles were detected, with an average of 8.5 per marker pair. The gene diversity averaged at 0.6671. The Polymorphism Information Content (PIC) values averaged of 0.68 showing the highly polymorphic and discriminatory nature of the selected markers. The accessions showed lower mean of observed heterozygosity (Ho = 0.187) than the expected heterozygosity (He = 0.547). AMOVA calculated low variants among populations (1%), and moderate variants within individuals (20%). However, variants among individuals were relatively high within population (79%). The fixation indexes showed little genetic differentiation among populations (FST = 0.008, P = 0.012). However, in the total population high level of inbreeding (FIS = 0.802, P = 0.001) was exhibited with deviation from Hardy-Weinberg proportions (FIT = 0.804, P = 0.001). Neighbor joining rooted phylogeny tree based on genetic similarity coefficient revealed three distinct groups independent of their geographic origins clustering close to each other; groups also have sub-groups. The study estimated genetic diversity and structure of Sudanese sorghum accessions.
Keywords: sorghum land races and accessions, SSRs markers, genetic diversity, analysis of molecular variants (AMOVA), cluster analysis, Sudan.