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Abstract Fermentation of cereal-made dough was the primary Ethiopian food for many years. Sourdough is believed to have many beneficial fermenting micro-floras depending on the source of dough and environmental conditions. The study aimed to isolate and characterize yeasts from fermenting cereal dough and evaluate their leavening potential for wheat dough. Morphological and biochemical characterizations such as sugar fermentation, glucose tolerance test, growth at different pH and temperatures, and agitation effect were employed to select potent yeasts. Accordingly, 16 potential yeast isolates were selected and subjected to further analysis. Finally, the yeasts were tested and compared for their leavening activity on the wheat dough at 37 °C and room temperature. Results revealed marvelous CO2 producer mesophile yeasts that degrade various sugars and tolerate up to 60% glucose concentration. The overall characterization assigned all the yeast isolates to the genus Saccharomyces and the Candida humilis. ANOVA showed that leavening activity by the yeast isolates was statistically higher at 37 °C compared to room temperature. The highest dough volume (6.2 mL) was recorded from Wh17, Wh5, and Ba12 isolates. Sor9 isolates were among the yeast that raised a minimum dough volume (0.7 mL). In contrast to commercial yeasts, the present study detected exceptional yeasts that matured within 24 h. Therefore, the discovered potential yeasts can be used for leavening dough in a short fermentation time and add aroma to baked products, making them a candidate in the baking industry. It could also be cost-effective as it could reduce media consumption and electricity utilization.

Sesame is an important oilseed crop cultivated in Ethiopia as a cash crop for small holder farmers. However, low yield is one of the main constraints of its cultivation. Boosting and sustaining production of sesame is thus timely to achieve the global oil demand. This study was, therefore, aimed at identifying mutant genotypes targeted to produce better agronomic traits of M2 lines on fourteen Ethiopian sesame genotypes through seed treatment with chemical mutagens. EMS was used as a chemical mutagen to treat the fourteen sesame genotypes. Quantitative and qualitative data were recorded and analyzed using analysis of variance with GenStat 16 software. Post-ANOVA mean comparisons were made using Duncan's Multiple Range Test (p≤ 0.01). Statistically significant phenotypic changes were observed in both quantitative and qualitative agronomic traits of the M2 lines. All mutant genotypes generated by EMS treatment showed a highly significant variation for the measured quantitative traits, except for the traits LBL and LTL. On the other hand, EMS-treated genotypes showed a significant change for the qualitative traits, except for PGT, BP, SSCS, LC, LH and LA traits. Mutated Baha Necho, Setit 3, and Zeri Tesfay showed the most promising changes in desirable agronomic traits. To the best of our knowledge, this study represents the first report on the treatment of sesame seeds with EMS to generate desirable agronomic traits in Ethiopian sesame genotypes. These findings would deliver an insight into the genetic characteristics and variability of important sesame agronomic traits. Besides, the findings set up a foundation for future genomic studies in sesame agronomic traits, which would serve as genetic resources for sesame improvement.

This study aimed at investigating the effects of sodium azide (NaN3) on quantitative and qualitative capsule traits in M2 generation of 14 Ethiopian sesame genotypes collected from Humera Agricultural Research Center (HuARC), Tigrai. Both the treatment and control seeds were sown in well-prepared beds in greenhouse to develop M2 plants. Data on quantitative and qualitative traits were collected and analyzed using GenStat 16 software. Results showed significant differences among the M2 seeds treated with 0.75% NaN3. The highest mean number of capsules per plant was recorded in ACC44 and Baha Necho genotypes, while the lowest was recorded in Gumero, Setit 2, Hirhir, ADI, Bounji and Aberghele. The highest mean number of seeds per capsule was recorded in Humera 1, Baha Necho, Zeri Tesfay, and Gondar 1 genotypes and the lowest was recorded in Setit 1, Setit 2 and ADI. The highest mean capsule length was observed in Zeri Tesfay while the lowest was recorded in Aberghele. The qualitative data reported that Hirhir, Setit 1 and Setit 2 were changed from completely shattering to partially shattering, Gumero and Bounji were changed from completely shattering to non-shattering, and Zeri Tesfay was changed from partially shattering to non-shattering. The 14 genotypes were clustered into four distinct groups including cluster I containing six genotypes, cluster II and III containing two genotypes each and cluster IV containing four genotypes. The mutants developed from Zeri Tesafy, ACC44 and Baha Necho genotypes are considered as potential candidate mutants for further utilization in sesame improvement.

The present study explored the effect of sodium azide (NaN3) on quantitative and qualitative leaf traits of M2 lines on 14 Ethiopian sesame genotypes collected from Humera Agricultural Research Center, Tigrai, Ethiopia. Qualitative data on leaf color, leaf hairiness, leaf arrangement, leaf shape, basal leaf profile, basal leaf margin, and leaf angle to main stem as well as quantitative data on length of basal leaf, length of top leaf, width of basal leaf, width of top leaf, length of marginal leaf, and width of marginal leaf were recorded and analyzed using analysis of variance, clustering analysis, Mahalanobis distance, and principal component analysis. Generally, treatment of seeds with NaN3 has brought many distinct and statistically significant phenotypic changes on both quantitative and qualitative leaf traits of the M2 lines. The changes in the NaN3 treated and locally adapted genotypes of Gumero and Zeri Tesfay are promising; producing the highest mean length of basal leaf (p ≤ 0.01). NaN3 treated seeds of Baha Necho, Gumero, and Hirhir developed the highest mean width of basal leaf. Locally adapted genotypes have responded positively to NaN3 treatment, generating better leaf traits as compared to the research improved ones. This study was the first of its kind in exploring the effects of NaN3 seed treatment on leaf traits of sesame genotypes. The findings of this study will, therefore, serve as a steppingstone to look into the effects of the changes in sesame yield and initiate future genetic and molecular studies on the responsive genotypes.