Four hundred and fifteen sorghum (Sorghum bicolor (L.) Moench) accessions consisting of 391 landraces collected from different geographical regions in Ethiopia and Eritrea, 8 varieties and 16 introduced elite breeding lines were used for this study. The materials were classified on the basis of regions of origin and adaptation zones. Phenotypic variation for ten qualitative (categorical) characters that displayed two or more classes were estimated using the Shannon‐Weaver diversity index (H'). High and comparable levels of phenotypic variation were found between the regions of origin and between the adaptation zones. However, significant levels of variation were found within the regions of origin and within the adaptation zones. Partitioning of the variation into within and between regions as well as into within and between adaptation zones further confirmed that a large portion of the total variation was found within regions of origin and within adaptation zones. Panicle compactness and shape contributed relatively more to regional differentiation. These characters were also found to be disproportionately distributed within the regions of origin with the compact panicles frequently distributed in relatively dry regions, while the loose panicle types were widely found in relatively wet and humid regions. The differential distribution of the different panicle types indicated the adaptive significance of panicle compactness and shape and at the same time reflected the distribution patterns of different races of sorghum in Ethiopia. Chi‐square analysis revealed that the occurrence of seed colour was non‐randomly associated with that of the other characters.

The extent and distribution of genetic variation in wild sorghum (Sorghum bicolor ssp. verticilliflorum (L.) Moench) collected from five different geographical regions in Ethiopia were analyzed using random amplified polymorphic DNA (RAPD) markers for 93 individuals representing 11 populations. Nine decamer primers generated a total of 83 polymorphic bands with 8-12 bands per primer and a mean of 9 bands across the 93 individuals. The amount of genetic variation among the populations (H = 0.37) and among the geographical region (H = 0.44) was low to moderate, despite the high degree of polymorphic bands per primer. Similarly, the mean genetic distance (0.08) among populations as well as among regions of origin (0.04) of the population was found to be low. The low genetic variation may be due to the reduced population size of the wild sorghum in Ethiopia because of habitat change. Partitioning of the genetic variation into between and within the population as well as between and within the regions of origin revealed that 75% and 88% of the variation was found within the populations and within the regions, respectively. Cluster analysis of genetic distance estimates further confirmed low level of differentiation of wild sorghum populations both on population and regional bases. The implications of the results for genetic conservation purposes are discussed.

Background: Tomato has significant economic importance in Ethiopia. Although quantitative evidence is limited, postharvest loss in tomato is considerably high. This study presents qualitative and quantitative postharvest losses of tomato. The study was conducted in 2015 in two districts (Bora and Dugda) located in East Shewa Zone of Oromia National Regional State, Ethiopia, located southeast of Addis Ababa. Primary data were collected from producers (smallholder farmers) and traders via household survey, focus group discussions and key informant interviews as well as estimation of losses based on samples. Secondary data and information were collected from published and unpublished sources. Results:Results indicate that tomato production is being done by relatively young married individuals who have at least primary level education. About three-quarter of land holding is allocated for vegetable production, which largely takes place under irrigation during dry season. All sample producers sold more than 95% of their tomato produce, mostly to wholesalers as compared to collectors and retailers. Postharvest losses occur at collectors, wholesalers and retailers level. The finding indicates that more than 16% of respondents encounter produce losses due to high incidence of diseases, insect pest and mechanical injuries, each of them accounting for more than 20% of postharvest losses. Conclusions:The findings from our study underscore that the ability of actors to mitigate postharvest losses is limited due to lack of technical know-how. They also lack necessary support and complementary resources to improve postharvest handling practices and technology.

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The experiment was conducted to assess the effects of nitrogen (N) rate and time of application on N use efficiency (NUE) of bread wheat, and their association with grain yield and protein content. Factorial combinations of four N levels, two bread wheat varieties and three timings of N applications were laid out in a randomized complete block design. N rate significantly influenced grain yield, protein content, N uptake efficiency, N biomass production efficiency, N utilization efficiency, N use efficiency for grain and N use efficiency for protein yield. Time of N application had highly significant effect on grain yield, protein content and NUE traits. Rate of N application and variety were significantly interacted to influence grain yield. Grain yield for Madda Walabu found sharply increase with each increase in N application rate. The improved variety provided significantly higher grain yield, N utilization efficiency and N use efficiency for grain yield (NUEGY) when N was applied 1/4 at planting, 1/2 at mid-tillering, and 1/4 at anthesis. Variations in NUEGY were explained more by the variations in N uptake efficiency. Harvest index contribution to NUEGY was higher for the local variety. Although NUE significantly decreased with increasing N rates, yield response of the varieties did not plateau out.

The amount and distribution of genetic variation was investigated in 48 sorghum landrace accessions, representing 13 regions of origin and three adaptation zones (lowland, intermediate and highland elevation) in Ethiopia and Eritrea. Assaying 11 enzymes systems, 23 putative loci were scored for a total of 27 alleles. Nineteen loci were monomorphic and fixed for the same allele, while the remaining 4 loci, each with 2 alleles, were polymorphic across the 48 accessions. The results show significant differences in allele frequencies among the accessions, regions of origin and the adaptation zones. However, all measures of genetic variation used show that the accessions maintained much lower levels of variation than the corresponding mean values for self-pollinating crop plants, confirming previous conclusions that sorghum is depauperated in allozymic variation. The total gene diversity was 0.25, which partitioned 59% within and 41% among accessions. The latter was largely due to variation among accessions within the adaptation zones (38%), while only 3% was due to variation among accessions between the adaptation zones. Similarly, most of the total gene diversity was found within the regions of origin (80%) and within the adaptation zones (97%). Both the dendrogram constructed from NEI's unbiased genetic distance and the plot of the first two principal components distinguished three groups of regions. The level of gene flow was low among accessions, regions of origin and among accessions within adaptation zones, but high among adaptation zones. The results are discussed with emphasis on genetic resources conservation and utilization.

To assess broad sense heritability and phenotypic and genetic correlations among sugarcane yield components, an experiment was conducted at Wonji and Metehara Sugar Estates of Sugar Corporation of Ethiopia during 2012/2013. High broad sense heritability (h 2 ) was detected for stalk diameter (0.730), single cane weight (0.672), millable cane number (0.624), stalk height (0.624) and pol % (0.608), indicating that these traits could be selected for easily. Expected genetic gain of the yield components was moderate to high. All traits had low to high genetic correlations (rg = −0.005 to 0.884) with cane yield and (rg = 0.027 to 0.999) with sugar yield. On average genetic correlations were higher than phenotypic correlations. High Genotypic Coefficient of Variation (GCV), broad sense heritability and expected genetic advance were recorded for stalk diameter, single cane weight and millable cane number. A selection strategy based on these traits could lead to improvement in cane and sugar yield.