Abstract

Genetic diversity assessment of genetic resources maintained at Gene-Banks has important implication for future improvement, conservation and collection activities. However, such information is not available for sesame collected by IBC, Ethiopia. Inter simple sequence repeat (ISSR) marker was used to assess the level of genetic diversity, genetic structure and genetic distance, and to indirectly estimate the level of gene flow among populations of sesame in Ethiopia. A total of 120 (82 Ethiopian and 38 exotic) sesame accessions and six ISSR primers were used. DNA was extracted using a triple CTAB extraction method from silica gel dried bulked sample of five randomly selected individual plants per accession at the stage of three to four weeks after planting. The presence of higher polymorphism was revealed among accessions collected from Ethiopia (75.85) than the exotic accessions (65.52). The average gene diversity relative to the overall population was 0.24. Samples from Welega was the most diverse, with gene diversity value of 0.26 followed by samples from Tigray (0.20) and Shewa (0.20). Samples from Gojam (0.10) and Sudan (0.12) were the least diverse. Inter-population genetic distance (D) ranged from 0.031 to 0.165 for the overall population. From the exotic accession, samples of South East Asia are distantly related to most of the Ethiopian accessions. Unweighted pair group method with arithmetic mean analysis (UPGMA) of Ethiopian sesame populations revealed two major groups and three outliers (Cultivated, Welega and Illubabore).

Key words: Bulk sampling, gene flow, genetic differentiation, genetic distance, inter simple sequence repeat (ISSR), genetic diversity and sesame landrace accessions.