Direct Organogenesis of Citrus Cultivars from Shoot Tip Nodal Segments.

BACKGROUND: Citrus cultivar improvement via conventional breeding strategies is impeded by factors related to its reproductive biology. The orange is a hybrid between pomelo (Citrus maxima) and mandarin (Citrus reticulata). Among various orange cultivars, Valencia oranges have a bit of bitter tang mixed in with their sweetness, as Navel oranges are, the most widely cultivated citrus species, quite sweeter, and also don't contain any seeds. Tangelo mandarin orange cultivar is a hybrid of C. reticulata × C. maxima or × C. paradisi. OBJECTIVE: The present study was undertaken to optimize the hormonal composition of the media with regard to plant growth regulators for in vitro propagation of sweet orange cultivars from nodal segment explants. METHODS: The nodal segment explants were collected from three citrus cultivars, Washington Navel, Valencia and Tangelo. Murashige and Skoog (MS) medium supplemented with sucrose and different concentrations of growth regulators was used for shoot proliferation and root induction, and the optimum medium composition was assessed. The patent for Citrus Tissue Culture was obtained from the Office of Research Affairs, Haramaya University. RESULTS: The results indicate that the highest shoot response was recorded for Washington's navel with maximum shoot proliferation rate (99.75%), shoot number per explant (1.76), shoot length (10.70 cm), leaf number per explants (3.54) after three weeks of culture. In all experiments, no growth was observed for the basal MS medium. Phytohormone combinations of IAA (1.2 mg/L) and kinetin (2.0 mg/L) were found to be the best for shoot proliferation. Among the cultivars, there were significant differences for the highest rooting rate (81.255), root number (2.22), and root length (2.95 cm) variables for Washington Navel. The lowest rooting rate (48.45%), root number (1.47) and root length (2.26 cm) were observed for Valencia. The highest rooting rate (84.90%), root number per microshoot (2.22) and root length (3.05 cm) was on MS medium supplemented with 1.5 mg/L NAA. CONCLUSION: A comparison of different concentrations of IAA and NAA on root induction of microshoots from nodal segments of citrus cultivars demonstrated NAA was a more effective hormone than IAA.

Morpho-agronomic variability of okra [Abelmoschus esculentus (L.) Moench] genotypes in Dire Dawa, eastern Ethiopia.

A total of 21 okra genotypes were evaluated for 25 morpho-agronomic traits in 2020 at Dire Dawa, Ethiopia in a randomized complete block design with three replications. Analysis of variance showed significant differences at p<0.05 level of significance for all traits. Estimates of genotypic (GCV) and phenotypic (PCV) coefficients of variation range from 9.16 to 42.3% and 9.33 to 44.16%, respectively. Heritability in a broad sense (H2) and genetic advance as a percent of the mean (GAM) ranged from 29.57 to 91.89% and 10.39 to 83.53%, respectively. Estimated variability components (GCV, PCV, H2, and GAM) were high and moderate for all traits except days to 50% emergence 9.33% of GCV and PCV, internode length 9.16% of GCV and green fruit width 29.57% of H2 that were categorized under low. The first four principal component axes (PCA1 to PCA4) accounted for 7.83 to 35.02%, which accounted 74.56% of the total variability with eigenvalues that ranged from 1.95 to 8.75. Genetic distances estimated by Euclidean distance from the 25 traits ranged from 2.33 to 12.56 with a mean of 6.83, standard deviation of 1.8, and a coefficient of variation of 26.46%. The genotypes were grouped into four distinct clusters using the Euclidean distance matrix using UPGMA. Indigenous okra genotypes collected from Ethiopia were more divergent with high genetic distances and had a higher performance for most of the traits including growth, green fruit yield, and seed yield than introduced genotypes. In conclusion, this study showed the presence of variation among genotypes for most of the traits, indicating that selection of genotypes could be effective to develop okra varieties with high green fruit and seed yield through direct selection or crossing.

Performances of three-way cross hybrids over their respective single crosses and related heterosis of maize (Zea mays L.) hybrids evaluated in Ethiopia.

Less attention had been given to the performances of three-way crosses and its comparative advantages of these hybrids over single crosses. This study was carried out to evaluate the performances of three-way crosses in comparison to single crosses for yield and related agronomic traits and to estimate the magnitude of heterosis. The trial was laid out in a simple alpha lattice design of 10 × 6 for lines, 6 × 5 for single crosses (SC), and 9 × 5 for three way-crosses and planted in adjacent plots in the 2019 cropping season in three locations namely Ambo, Abala-Farcha and Melkassa. Single cross hybrids showed a highly significant (P<1%) variation for grain yield, plant height, ear height, and ear length at three locations. These single cross hybrids had showed also a highly significant genotype by environment interaction (P < 1%) for grain yield, plant height, ear height and kernel per ear. Regarding three-way crosses, there was a significant variation (P<5%) on grain yield in Ambo and Melkassa but on ear height and rows per ear in Abala-Faracho. The genotype × environment interaction was significantly varied for grain yield, ear height and ear length. In the comparison, 80% crosses in Ambo, 73% in Abala-Faracho and 67% in Melkassa showed that three-way crosses were better in their performance than that of their respective single crosses. On the other hand, the single crosses that out-performed their respective three-way crosses were higher in Melkassa than Abala-Faracho and the least were reported from Ambo. Similarly, the maximum better and mid-parent heterosis was from single cross 1(769%) in Ambo and single cross 7 (104%) in Melkassa whereas TWC 14 (52%) and TWC 24 (78%) were the highest better and mid-parent heterosis, respectively in Ambo, TWC1 (56%), and TWC30 (25%) were the highest BPH, and MPH, respectively in Melkassa.

Duration of of Low-Temperature Storage, Clove Topping and Gibberellic Acid on Emergence, Yield and Yield Components of Garlic.

Dormancy of freshly harvested garlic cloves does not allow early emergence, and preplanting garlic clove treatment is critical for more than one cycle of production in a year. This field experiment was conducted to assess the effect of treating cloves on emergence, growth, and yield of "Tseday" variety during the main cropping season of 2014/2015 and off-season of 2015/16 at Haramaya University. The experiment was arranged in a factorial combination of four (cold stored at 7°C for the duration of 10, 20, and 30 days and stored at room temperature 21°C for 30 days as control), two (whole and topped clove), and four GA3 treatment at concentration of 0, 125, 250, and 375 mg/l and distilled water treatment as second control laid out in randomized complete block design with three replications. The three main factors (clove type, cold storage duration, and GA3) and growing season showed significant influence on phenology, growth, bulb yield and yield components, and all size categories of cloves, while GA3 showed nonsignificant effect on days to emergence of cloves. Clove type interacted with cold storage duration and GA3, and cold storage duration interacted with GA3 significantly to influence all characters of the variety. In addition, the growing season also interacted with clove type and GA3 to influence all categories of clove size, bulb diameter, average bulb weight, and total bulb yield. The three main factors (clove type × cold storage duration × GA3) interaction significantly influenced all characteristics of the variety. However, 30 days of cold-stored and topped cloves reduced dormancy period and days to maturity by 18.84 and 19.50 days, respectively, and increased total bulb yield by 70.32% as compared to the control treatment. In addition, this treatment combination significantly increased most of the growth and bulb yield components, while the number and weight of small-sized cloves were decreased. Hence, it can be concluded that 30 days of cold storage and topping of cloves without soaking under GA3 could be recommended to enhance early emergence, good vegetative growth, and total bulb yield of the garlic variety both under rain-fed and irrigated conditions.

Phenotypic Diversity Assessment of Okra (Abelmoschus Esculentus (L.) Moench) Genotypes in Ethiopia Using Multivariate Analysis.

Okra is a minor crop that has not gained research attention in Ethiopia. Characterization of such underutilized crops has important implications for their utilization. Thus, this study was conducted to assess the genetic diversity of okra genotypes in Ethiopia using agromorphological and biochemical markers. Thirty-six okra genotypes were evaluated for 29 agromorphological and biochemical traits. The results of the analysis of variance showed significant differences among genotypes for most of the traits, except for the number of flower epicalyx and fruit diameter. Results of the principal component analysis indicated that the first eight principal component axes accounted for 3.83 to 30.54% and 82.44% of the total variability. Genetic distances estimated by Euclidean distances from 27 traits ranged from 3.55 to 14.49. The 36 genotypes were grouped into four distinct clusters from the Euclidean distance matrix using the unweighted pair group method with arithmetic mean (UPGMA). The first cluster contained 24 (66.66%) genotypes, and the second cluster contained 10 (27.77%) of the genotypes. This study showed the presence of considerable genetic variation among the genotypes for most of the traits, including fruit yield, seed yield, and nutrient content of seeds, indicating the possibility of using these genotypes to develop okra varieties with high fruit-yielding and good nutritional content.

Nutritional and chemical properties of fermented food of wild and cultivated genotypes of enset (Ensete ventricosum).

The multipurpose crop enset (Ensete ventricosum) has been traditionally cultivated in Ethiopia since ancient times. The main food product is the starch-rich fermented kocho made from the pseudostem and corm. There are many vegetatively propagated landraces utilised by farmers, but no concisions breeding have taken place, and there are requests for improved cultivars. There are also populations of wild ensets which propagate sexually, and the variation in characteristics among the wild is not studied. We suggest investigating the variation among the wild, in order utilise the most proper combinations of parent plants when breeding for different purposes. We analysed kocho, after 30 and 90days of fermentation, from three wild genotypes and three cultivars, to compare how and how much they differ in components and perceived food quality. The three cultivars scored generally higher than all the three wild genotypes for protein, fat, sugar and minerals, while the wild had larger fraction of starch. On average, panellists rated all the cultivated significantly higher than all the wild regarding the investigated characteristics (colour, texture, taste and overall). However, there were nine out of 25 panellists who rated at least one wild genotype higher or equal to at least one cultivar regarding taste, showing that people can be open for unfamiliar kocho. Therefore, we conclude that further investigations of the variation among wild plants should be done, aiming to get a larger gene pool with improved characteristics as e.g. disease tolerance or superior mineral uptake; by careful selection of parent plants, desired combinations can be achieved.