| 1. |
- Elsafy, Mohammed, et al.
(författare)
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Elucidating the genetic diversity of farmer cultivars of female date palms (Phoenix dactylifera L.) from Sudan by microsatellite markers
- 2016
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Ingår i: Genetic Resources and Crop Evolution. - : Springer Science and Business Media LLC. - 0925-9864 .- 1573-5109. ; 63, s. 975-986
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Tidskriftsartikel (refereegranskat)abstract
- Genetic diversity in female date palms for a total of 89 tree samples, representing 18 cultivar groups, was investigated using 10 loci of microsatellite (SSR) primers. The microsatellites examined showed high polymorphism, a total of 126 for the 10 microsatellite loci, giving an average of 12.6. Low F-ST values were observed among different fruit classification groups of Sudanese date palms (soft, semi-soft and dry) suggesting that the observed high genetic variability is maintained locally within cultivars. Across all genetic parameters, in comparison among the cultivar groups, the Jaw group was consistently highly variable followed by Korsha, Gondela and Barakawi, respectively. Multivariate analysis of the 89 date palms showed some strong relationships with some mixed grouping, showing a tendency of relate fruit classification and related genotypes. Dry dates almost grouped together while the soft and semi-soft were mixed and somewhat related to genotypes. The effect of genotype was highly supported by the relationship of 14 cultivar groups, in which similar cultivars were associated regardless of the state to which they belong. Further detailed analyses of female date palm populations from different geographic locations represented by a minimum of five plants per cultivar is necessary to provide the basis for understanding of the date palm genomes, revealing the true extent of gene flow between farmer cultivars.
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| 2. |
- Juma, Ibrahim, et al.
(författare)
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Avocado Production and Local Trade in the Southern Highlands of Tanzania: A Case of an Emerging Trade Commodity from Horticulture
- 2019
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Ingår i: Agronomy. - : MDPI AG. - 2073-4395. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Avocado crop in Tanzania is sparingly investigated regardless of being an important fruit commodity. This study was undertaken to explore the yield and the value chain of this crop in the country. Data were collected mainly by face-to-face interviews with 275 avocado farmers, 231 avocado traders and 16 key informants. Descriptive statistics, Chi-square test and one-way analysis of variance were used for data analysis. The average crop yield ranged from 76 to 124 kg plant(-1) between regions. The average price for the farmers' produce ranged from US$ 0.30 to 0.45 kg(-1) between regions. About 72% of the farmers were dissatisfied with avocado business whereas 79% of the traders were pleased with it. A number of challenges were found hindering the development of the avocado industry in Tanzania, which in turn affects the fruit yield and the value chain. Addressing these challenges at the national, regional, district and village levels is important for improving the livelihood of Tanzanian farmers growing this crop, given the fact that a good proportion of the country's population is employed in the agricultural sector and most of the reported challenges also affect the value chain of other crops.
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| 3. |
- Juma, Ibrahim, et al.
(författare)
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Characterization of Tanzanian Avocado Using Morphological Traits
- 2020
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Ingår i: Diversity. - : MDPI AG. - 1424-2818. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Two-hundred and twenty-six old avocado trees (Persea americana Mill) derived from seeds were selected from eight districts of the Mbeya, Njombe and Songwe regions in Tanzania. The tree, leaf, fruit and seed characteristics were studied using the descriptors for avocado (Persea spp.) from the International Plant Genetic Resources Institute. Cross tabulation and Chi-square tests were conducted in order to assess the distribution of traits between districts and altitude ranges. Principle coordinate analysis (PCoA) and hierarchical cluster analysis (HCA) were used to assess variation of traits within and among districts. Various morphological features were observed among the samples which point to the existence of the Mexican, Guatemalan and West Indian avocado races in Tanzania. The biplot from PCoA revealed extensive variation between the sampled trees at the district level but no clear groupings of the samples based on geographic location. Likewise, dendrograms ensuing from the neighbor-joining and Wards methods displayed that the avocado samples from the same district and even region differed considerably. This morphological trait variation suggests high diversity that may help in planning germplasm management and conservation, as well as breeding strategies in the future.
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| 4. |
- Juma, Ibrahim, et al.
(författare)
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Comparison of morphological and genetic characteristics of avocados grown in Tanzania
- 2021
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Ingår i: Genes. - : MDPI AG. - 2073-4425. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Tanzania has been growing avocado for decades. A wide variability of the avocado germplasm has been found, and the crop is largely contributing to the earnings of the farmers, traders, and the government, but its genetic diversity is scantly investigated. With the purpose of comparing morphological and genetic characteristics of this germplasm and uncovering the correlation between them and the geographical location, 226 adult seedling avocado trees were sampled in southwestern Tanzania. Their morphological characters were recorded, and their genetic diversity was evaluated based on 10 microsatellite loci. Discriminant analysis of principal components showed that the germplasm studied consisted of four genetic clusters that had an overall average gene diversity of 0.59 and 15.9% molecular variation among them. Most of the phenotypes were common in at least two clusters. The genetic clusters were also portrayed by multivariate analysis and hierarchical clustering for the molecular data but not for the morphology data. Using the Mantel test, a weak significant correlation was found between the genetic, morphological, and geographical distances, which indicates that the genetic variation present in the material is weakly reflected by the observed phenotypic variation and that both measures of variation varied slightly with the geographical sampling locations.
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| 5. |
- Juma, Ibrahim, et al.
(författare)
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Genetic diversity of avocado from the southern highlands of Tanzania as revealed by microsatellite markers
- 2020
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Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 157
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Tidskriftsartikel (refereegranskat)abstract
- Background: Avocado is an important cash crop in Tanzania, however its genetic diversity is not thoroughly investigated. This study was undertaken to explore the genetic diversity of avocado in the southern highlands using microsatellite markers. A total of 226 local avocado trees originating from seeds were sampled in eight districts of the Mbeya, Njombe and Songwe regions. Each district was considered as a population. The diversity at 10 microsatellite loci was investigated. Results: A total of 167 alleles were detected across the 10 loci with an average of 16.7 ± 1.3 alleles per locus. The average expected and observed heterozygosity were 0.84 ± 0.02 and 0.65 ± 0.04, respectively. All but two loci showed a significant deviation from the Hardy-Weinberg principle. Analysis of molecular variance showed that about 6% of the variation was partitioned among the eight geographic populations. Population FST pairwise comparisons revealed lack of genetic differentiation for the seven of 28 population pairs tested. The principal components analysis (PCA) and hierarchical cluster analysis showed a mixing of avocado trees from different districts. The model-based STRUCTURE subdivided the trees samples into four major genetic clusters. Conclusion: High diversity detected in the analysed avocado germplasm implies that this germplasm is a potentially valuable source of variable alleles that might be harnessed for genetic improvement of this crop in Tanzania. The mixing of avocado trees from different districts observed in the PCA and dendrogram points to strong gene flow among the avocado populations, which led to population admixture revealed in the STRUCTURE analysis. However, there is still significant differentiation among the tree populations from different districts that can be utilized in the avocado breeding program.
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| 6. |
- Juma, Ibrahim, et al.
(författare)
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Polyphenolic Content and Radical Scavenging Activities of the Peel, Pulp and Seed of Avocado (Persea americana Mill.) Grown in Tanzania
- 2023
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Ingår i: Tanzania Journal of Science. - 0856-1761 .- 2507-7961. ; 49, s. 230-239
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Tidskriftsartikel (refereegranskat)abstract
- Avocado is a healthy fruit and the consumption is continuously growing worldwide. The fruit contains polyphenolic compounds with antioxidant effects. Globally, research has been devoted to exploring the fruit quality, especially compounds with antioxidant effects, from different avocado-growing sites. However, the fruit quality of the Tanzanian avocado has so far not been investigated. In this study, the contents of polyphenols in peel, pulp and seed of avocados sampled in south-western Tanzania are described. The levels of total polyphenolic and flavonoid contents were measured, and antioxidant activity was evaluated using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The total polyphenolic content was highest in the seed and lowest in the peel (424 and 200 mg GAE/100 g DW, respectively). As for the total flavonoid content, the pulp had the highest value of 36.98 mg RE/100 g DW, while the seed had the lowest value of 32.54 mg RE/100 g DW. The overall average half maximal effective concentration (EC50) values in decreasing order, corresponding to an increasing antiradical activity, were 4.90 (peel), 3.63 (seed) and 3.24 µg/mL (pulp). The seed and peel possessed high levels of total polyphenolic and flavonoid content, thus demonstrating substantial antioxidant capacity. Seed and peel can potentially be processed and included in the diet to provide inexpensive antioxidant ingredients of natural origin. Consumption of the seed will not only improve human health but also reduce the environmental pollution, as many thousand tonnes of avocado seeds are produced in Tanzania per year; a huge amount currently remains as waste.
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| 7. |
- Motlhaodi, Tiny, et al.
(författare)
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Genetic diversity in ex-situ conserved sorghum accessions of Botswana as estimated by microsatellite markers
- 2014
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Ingår i: Australian Journal Of Crop Science. - 1835-2693 .- 1835-2707. ; 8, s. 35-43
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Tidskriftsartikel (refereegranskat)abstract
- Simple sequence repeat (SSR) markers were used to characterize genetic diversity in 30 sorghum [Sorghum bicolor (L.) Moench] accessions conserved in the national gene bank of Botswana. This collection represents the three sorghum-growing agro-ecological zones in the country. Ten microsatellite primer pairs were used, and these generated a total of 53 alleles with three to seventeen alleles per locus across the 30 accessions. A high level of genetic variation was observed among the accessions (70% of the variation), and 30% of the total genetic variation was observed within accessions. The analysis of molecular variance on sorghum accessions grouped based on agro-ecological region, ethnicity, and sorghum race revealed a non-significant variation, indicating that the alleles are distributed all over the country. Cluster analysis also did not group the accessions according to agro-ecological region, race or ethnicity. The results of this study have indicated that substantial genetic diversity exists among sorghum accessions conserved in Botswana, but that agro-ecological region, ethnicity and race did not influence the distribution of this diversity
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| 8. |
- Motlhaodi, Tiny, et al.
(författare)
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Genetic diversity in sorghum [Sorghum bicolor (L.) Moench] germplasm from Southern Africa as revealed by microsatellite markers and agro-morphological traits
- 2017
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Ingår i: Genetic Resources and Crop Evolution. - : Springer Science and Business Media LLC. - 0925-9864 .- 1573-5109. ; 64, s. 599-610
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Tidskriftsartikel (refereegranskat)abstract
- Cultivated sorghum [Sorghum bicolor (L.) Moench] is an important food security crop in the semi-arid regions of the world including Asia and Africa. Its genetic diversity is contained mostly in traditional varieties and modern cultivars used by farmers. In this study, agro-morphological traits and molecular markers were used to assess genetic diversity in 22 accessions of cultivated sorghum from five countries (Botswana, Namibia, Swaziland, Zambia and Zimbabwe) in the Southern African Development Community (SADC) region. The study revealed a significant variation among 22 accessions in both qualitative and quantitative morphological traits, indicating the accessions’ promising potential as breeding material. For molecular analysis, 11 microsatellite primer-pairs were used, and generated a total of 70 alleles across 20 accessions. Analysis of molecular variance revealed a high level of genetic variation; 67 % among the accessions and 10 % among the five countries. The patterns of genetic diversity and the relationships observed in this study should provide insights for genetic resource conservation and utilization of sorghum germplasm in the SADC region.
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| 9. |
- Motlhaodi, Tiny, et al.
(författare)
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Nutritional variation in sorghum [Sorghum bicolor (L.) Moench] accessions from southern Africa revealed by protein and mineral composition
- 2018
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Ingår i: Journal of Cereal Science. - : Elsevier BV. - 0733-5210 .- 1095-9963. ; 83, s. 123-129
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Tidskriftsartikel (refereegranskat)abstract
- Twenty-three sorghum accessions from five countries in southern Africa that were grown under two different environments in Botswana were analyzed for protein, calcium (Ca), iron (Fe), magnesium (Mg), manganese (Mn), phosphorus (P), potassium (K), sodium (Na) and zinc (Zn) concentrations. There were significant differences among the accessions for both protein and other nutrient contents. Broad-sense heritability (H-2) was overall high, ranging from 0.62 to 0.85, indicating the stability of the concentration of these nutrients in sorghum across environments. Low genotype by environment interactions (GxE) and high broad-sense heritability suggest that breeding for enhanced nutrient content may be feasible across environments. Accessions ZMB3947 and N406 may be a good source for both Fe and Zn since they recorded the highest value for both micronutrients. Among the macronutrients, accession S201 would be a good source of protein, Ca and P whereas accession ZIM1317 is a good choice as a Ca and K source. The genotypic variation in grain protein and mineral concentration revealed in this study is encouraging for selecting potential accessions for genetic improvement through breeding in Southern Africa. There were significant correlations among nutrients, which suggests that their concentration in sorghum landraces can be simultaneously improved.
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| 10. |
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| 11. |
- Mujaju, Claid, et al.
(författare)
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Genetic diversity in watermelon (Citrullus lanatus) landraces from Zimbabwe revealed by RAPD and SSR markers
- 2010
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Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 147, s. 142-153
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Tidskriftsartikel (refereegranskat)abstract
- Low polymorphism in cultivated watermelon has been reported in previous studies, based mainly on US Plant Introductions and watermelon cultivars, most of which were linked to breeding programmes associated with disease resistance. Since germplasm sampled in a putative centre of origin in southern Africa may harbour considerably higher variability, DNA marker-based diversity was estimated among 81 seedlings from eight accessions of watermelon collected in Zimbabwe; five accessions of cow-melons (Citrullus lanatus var. citroides) and three of sweet watermelons (C. lanatus var. lanatus). Two molecular marker methods were used, random amplified polymorphic DNA (RAPD) and simple sequence repeats (SSR) also known as microsatellite DNA. Ten RAPD primers produced 138 markers of which 122 were polymorphic. Nine SSR primer pairs detected a total of 43 alleles with an average of 4.8 alleles per locus. The polymorphic information content (PIC) ranged from 0.47 to 0.77 for the RAPD primers and from 0.39 to 0.97 for the SSR loci. Similarity matrices obtained with SSR and RAPD, respectively, were highly correlated but only RAPD was able to provide each sample with an individual-specific DNA profile. Dendrograms and multidimensional scaling (MDS) produced two major clusters; one with the five cow-melon accessions and the other with the three sweet watermelon accessions. One of the most variable cow-melon accessions took an intermediate position in the MDS analysis, indicating the occurrence of gene flow between the two subspecies. Analysis of molecular variation (AMOVA) attributed most of the variability to within-accessions, and contrary to previous reports, sweet watermelon accessions apparently contain diversity of the same magnitude as the cow-melons.
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| 12. |
- Mujaju, Claid, et al.
(författare)
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Variationsrika vattenmeloner i södra Afrika
- 2012
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Ingår i: LTJ-fakultetens faktablad.
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Annan publikation (populärvet., debatt m.m.)abstract
- På soliga semesterresor till varmare länder, har allt fler svenskar lärt sig att uppskatta de stora, läskande vattenmelonerna. Ingenting släcker törsten bättre, och säkrare, än en generös skiva saftig vattenmelon med sitt karaktäristiska spröda och rosaröda fruktkött. Tillgången är inget problem; det finns knappast något tropiskt eller subtropiskt land (vattenmelon växer bäst vid 20–30 °C) som inte kan erbjuda lokalodlade vattenmeloner. Minst 55 länder producerar vattenmeloner, och den samlade produktionen beräknas till över 100 millioner ton per år. I odlingsanalyser betraktas vattenmelon som en grönsak, och den odlas på drygt 10% av den areal som används till grönsaker
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| 13. |
- Muzila, Mbaki, et al.
(författare)
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Assessment of diversity in Harpagophytum with RAPD and ISSR markers provides evidence of introgression
- 2014
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Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 151, s. 91-101
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Tidskriftsartikel (refereegranskat)abstract
- The genus Harpagophytumhas two species: H. procumben swhich is an important medicinal plant in southern Africa, and H. zeyheri. Genetic diversity in 96 samples, obtained by germinating seeds collected from Botswana, was assessed using six inter-simple sequence repeat (ISSR) and 10 random amplified polymorphic DNA (RAPD) primers. These DNA markers yielded a total of 138 polymorphic bands. Polymorphism information content (PIC) ranged from 0.06 to 0.39 for ISSR primers, and from 0.09 to 0.43 for RAPD primers. Jaccard's similarity coefficients were highest when seedlings derived from the same fruit capsule were compared, while seedlings from different fruits on the same plant had intermediate values. The lowest values were recorded among seedlings from different plants. These results were consistent with an outcrossing breeding system in Harpagophytum. Analysis of molecular variance revealed significant differentiation (P < 0.01) between taxonomic units within Harpagophytum. About 39% of the variability occurred between the two species, H. procumbens and H. zeyheri. Plants with an intermediate morphology, i.e. putative hybrids (PH), showed 21% differentiation when compared with H. procumbens ssp. procumbens (PP), and 19% when compared with H. procumbens ssp. transvaalense (PT) or with H. zeyheri (ZZ). In addition, a deviating variant of PT was identified, here termed ‘procumbens new variety’ (PN). PN showed only 9% differentiation when compared with PT, 22% when compared with PP or with PH, and 41% when compared with ZZ. Considerable differentiation between the two Harpagophytum species was revealed also by a cluster analysis. Introgression was, however, suggested by the intermediate position of the putative hybrid plants in a principal component analysis while inter-specific gene flow was shown by a Bayesian genetic structure analysis.
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| 14. |
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| 15. |
- Ng'uni, Dickson, et al.
(författare)
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Comparative genetic diversity and nutritional quality variation among some important Southern African sorghum accessions (Sorghum bicolor (L.) Moench)
- 2012
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Ingår i: Australian Journal Of Crop Science. - 1835-2693 .- 1835-2707. ; 6, s. 54-64
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Tidskriftsartikel (refereegranskat)abstract
- Determination of genetic diversity and nutritional value is useful for varietal improvement. Fourteen sorghum accessions, six from Malawi (MW), four each from Tanzania (TZ) and Zambia (ZMB) considered most common and widely grown varieties in those countries were assessed for genetic diversity based on ten SSR loci and grain-Fe, Zn, total protein and starch contents. Sorghum accessions exhibited significant variation for protein, total starch content and grain-Zn (p<0.001) and grain-Fe (p<0.05). Grain-Fe content ranged from 2.8 to 6.3 mg/100g and grain-Zn content ranged 2.3 - 5.5 mg/100g. Grain protein content ranged from 9.7 to 16.3%. TZ4031 from Tanzania was superior in grain-Zn content while MW734 from Malawi was high in grain-Fe and protein contents. Zambian accessions were significantly higher in total starch content. Similarly, Tanzanian accessions were significantly superior in grain-Zn content. Protein content was significantly positive correlated with grain-Zn (r = 0.42). Significant and highly positive correlation (r = 0.49) was revealed between grain-Fe and Zn content. Nei’s gene diversity revealed higher genetic variation within Malawian accessions than in other accessions used in the study. The lowest within accessions genetic diversity was exhibited by Tanzanian accessions. Cluster and principal coordinate analyses revealed similarity between Malawian and Tanzanian accessions. The results suggest presence of genetic diversity for grain-Fe, Zn, protein and starch contents for food purposes and as resource for varietal improvement. MW734, TZ4031 and TZ3966 were identified as a potential resource material for grain-Fe and Zn variety enrichment programme. However, further research is recommended for evaluation of the compositional stability of potential sorghum accessions across various environmental conditions
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| 16. |
- Ng'uni, Dickson, et al.
(författare)
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Phylogenetic analysis of the genus Sorghum based on combined sequence data from cpDNA regions and ITS generate well-supported trees with two major lineages
- 2010
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Ingår i: Annals of Botany. - : Oxford University Press (OUP). - 0305-7364 .- 1095-8290. ; 105, s. 471-480
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aims Wild Sorghum species provide novel traits for both biotic and abiotic stress resistance and yield for the improvement of cultivated sorghum. A better understanding of the phylogeny in the genus Sorghum will enhance use of the valuable agronomic traits found in wild sorghum.Methods Four regions of chloroplast DNA (cpDNA; psbZ-trnG, trnY-drnD, trnY-psbM and trnT-trnL) and the internal transcribed spacer (ITS) of nuclear ribosomal DNA were used to analyse the phylogeny of sorghum based on maximum-parsimony analyses.Key Results Parsimony analyses of the ITS and cpDNA regions as separate or combined sequence datasets formed trees with strong bootstrap support with two lineages: the Eu-sorghum species S. laxiflorum and S. macrospermum in one and Stiposorghum and Para-sorghum in the other. Within Eu-sorghum. S. bicolor-3, -11 and -14 originating from southern Africa form a distinct clade. S. bicolor-2, originally from Yemen, is distantly related to other S. bicolor accessions.Conclusions Eu-sorghum species are more closely related to S. macrospemum and S. laxiflorum than to any other Australian wild Sorghum species. S. macrospermum and S. laxiflorum are so closely related that it is inappropriate to classify them in separate sections. S. oilman is closely associated with S. bicolor, suggesting that the latter is the maternal parent of the former given that cpDNA is maternally inherited in angiosperms. S. bicolor-3. -11 and -14, from southern Africa, are closely related to each other but distantly related to S. bicolor-2.
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