This study was conducted to assess regional patterns of diversity of Ethiopian tetraploid wheat accessions and to identify areas of diversity that can be used as source of new germplasm for developing high yielding and stable varieties. A collection of 133 Ethiopian tetraploid wheat accessions and eight introduced cultivars was analysed using 29 wheat microsatellite markers. A total of 383 alleles were detected with an average value of 13.14 alleles per locus. Relatively more alleles were observed in the B genome than in the A genome. Gene diversity indices ranged from 0.08 to 0.95, with a mean value of 0.72. Accessions collected from the same region were pooled and the number of alleles and gene diversity were calculated over the 29 simple sequence repeats for each region. Higher numbers of alleles were detected in the Shewa region (8.72), followed by Tigray (5.86) and Hararghe (5.76). The highest average gene diversity value was found in Shewa (0.65), followed by Gondar (0.64). No significant correlation was observed between geographic distance and genetic distance. Out of 383 different alleles detected, 93 (24.4%) were observed to be region-specific. Region-specific alleles were found across all chromosomes except for Xgwm752, Xgwm155 and Xgwm148. Genetic similarity coefficients were estimated for all the possible 55 pairs of regional comparisons and they ranged from 0.16 to 0.52, with a mean value of 0.50. All provinces were differentiated in the UPGMA cluster diagram.

A population of 77 recombinant inbred lines (RILs) were developed through single-seed descent from a cross between 'PAC-2' and 'RHA-266'. Seeds of the above-mentioned RILs and their parents were planted in the field in a randomised complete block design with two replications. Genetic control for some agronomical traits-sowing-to-flowering date, plant height, stem diameter (SD), head diameter (HD), grain weight per plant, 1,000-grain weight (TGW) and the percentage of oil in grains-were measured for RILs and their parents. Genetic variability was observed among 77 RILs for all traits studied. Transgressive segregation occurred for some traits, and the comparison between 10% of selected RILs with the best parent showed significant difference for SD and HD as well as for TGW. A set of 123 RILs from the same cross, including the 77 above-mentioned RILs and their two parents, were screened with 409 AFLP and SSR markers, and a linkage map was constructed based on 367 markers. Several QTLs associated with the studied traits were identified. The effects of each QTL are moderate, ranging from 7% to 37%, but a high percentage of phenotypic variance is explained when considering all the covariants (TR2 mean around 80% in each trait). Although the detected regions need to be more precisely mapped, the information obtained should help in marker-assisted selection.

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The AFLP and SSR markers were used to estimate the genetic diversity of 25 Brassica napus hybrids attending Guizhou regional test. The fingerprints obtained with both the AFLP and SSR markers revealed high levels of heterozygosity. Nine AFLP primer combinations produced 16 loci, while 11 SSR primer pairs generated 22 loci. The mean of expected heterozygosity, Shannon's information index, and genetic differentiation obtained by SSR were higher than those by AFLP, indicating that the SSR methodology evaluated genetic diversity among B. napus more efficiently than the AFLP approach. The higher level of genetic diversity detected by SSR markers was contributed to the lower genetic similarity estimates based on SSR markers (mean 0.69) as compared to AFLP markers (mean 0.73). While the AFLP technique was suitable for identification and DNA fingerprinting of B. napus germplasm. Based on AFLP and SSR analysis, it was concluded that B. napus hybrids had high level genetic diversity.