| 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. |
- Elsafy, Mohammed, et al.
(författare)
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Phenotypic Diversity of Date Palm Cultivars (Phoenix dactylifera L.) from Sudan Estimated by Vegetative and Fruit Characteristics
- 2015
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Ingår i: International Journal of Biodiversity. - : Hindawi Limited. - 2314-4149 .- 2314-4157.
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to apply some of the vegetative and fruit traits which are easily recognised to identify the variation and the diversity level of the most famous Sudanese date palm cultivars grown on farm in the northern region of Sudan. Sixteen phenotypic traits consisting of ten quantitative and six qualitative characteristics were used for describing the vegetative and fruit characteristics. The principal components analysis (PCA) and UPGMA clustering were used to analyse the data set. The results revealed high variability among the cultivars according to PCA. Fourteen out of the sixteen quantitative and qualitative traits investigated showed a strong discriminating factor suggesting their possible uses in the initiation of Sudanese date palm morphological descriptor list. UPGMA clustering exhibited strong relationship between some cultivars according to their fruit and vegetative characteristics similarity. Based on morphological traits, cultivars Wad-laggi (Lag) and Wad-khateeb (Kha) formed a distinct group suggesting their close relatedness. Similarly, the cultivars sharing the dry fruit texture such as Gondaila (Gon), Tamoda (Tam), Kolmah (Kol), and Barkawi (Bar) were grouped together according to their vegetative traits. Further investigations on Sudanese date palm using more phenotypic characteristics are recommended in order to shape and complete the set of the morphological descriptor list.
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| 4. |
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| 5. |
- Mujaju, Claid
(författare)
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Diversity of landraces and wild forms of watermelon (Citrullus lanatus) : distribution and implications for conservation in southern Africa, with emphasis on Zimbabwe
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Watermelon (Citrullus lanatus) is commonly grown in traditional agrosystems throughout the drought-prone Southern Africa as a staple food (edible seeds), a dessert food (edible flesh), and for animal feed. Several morphotypes of watermelon are found in this area; sweet watermelon, cooking melon and seed melon landraces of the traditional agrosystems; and possibly introgressed types which are regarded as agronomic weeds. There has been little work on investigating the relationships between wild and cultivated forms, and to study amount and partitioning of genetic variation, to allow for better conservation strategies. Previous studies have reported relatively low levels of genetic diversity in cultivated watermelon but these have been based mainly on US plant introductions and modern watermelon cultivars linked to breeding programmes for disease resistance. By contrast, germplasm maintained in the putative centre of origin in southern Africa, can be expected to display considerably higher variability. Three different sampling strategies were used to collect plant material of both wild and cultivated forms of cow-melons (Citrullus lanatus var. citroides) and of sweet watermelons (C. lanatus var. lanatus, only known from cultivation); (1) in-depth sampling in the fields of one village in Zimbabwe, (2) medium-scale sampling across the watermelon growing districts in Zimbabwe, and (3) broad-scale sampling across Southern Africa (Botswana, Namibia, South Africa, Zambia and Zimbabwe). Two molecular marker methods were used, random amplified polymorphic DNA (RAPD) and simple sequence repeats (SSR) also known as microsatellite DNA. Similarity matrices obtained with RAPD and SSR, respectively, have been highly correlated, suggesting that for some applications, the less demanding RAPD can be a useful alternative, especially in developing countries. Considerable amounts of genetic diversity were found at all levels, including within-accessions (half-sib families). Sweet watermelon accessions appear to contain almost as much variability as cow-melon accessions. A genetic structure analysis divided the wild-weed-landrace complex collected in one village into three groups confirming the existence of three major forms with limited admixture. Defining the major forms into landraces and/or folk varieties was considered critical for identification of proper units for both on-farm and ex-situ conservation. Distribution of most watermelon accessions in Zimbabwe was associated with sandy loam and sand soils.
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| 6. |
- Mujaju, Claid
(författare)
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Diversity of landraces and wild forms of watermelon (Citrullus lanatus) in southern Africa : a synopsis of the PhD Study
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The genus Citrullus, belongs to the Cucurbitaceae family. Among the four species in this genus, a single species Citrullus lanatus (Thunberg) Matsum. & Nakai, commonly known as watermelon, is grown throughout the drought-prone southern Africa as a staple food (edible seeds), a dessert food (edible flesh), and for animal feed. The fruit can be eaten fresh or cooked and the seeds can be roasted. Its uses are however, multifaceted and vary depending on the customs of the humans growing this crop. In addition, the fruit can serve as a source of water, especially in deserts or where drinking water is contaminated. Several morphotypes of watermelon are found in southern Africa. Citrullus lanatus exhibits expansive polymorphism in southern Africa and the species occurs in the following forms: wild populations distributed throughout the country in a wide range of habitat types; sweet watermelon, cooking melon and seed melon landraces of the traditional agrosystems; and possibly introgressed types which are regarded as agronomic weeds. Farmers’ traditional onfarm practices contribute to the maintenance of watermelon landraces, and therefore play a role in nurturing local-level diversity. The wild watermelon is widely distributed in Africa and Asia, but originates from southern Africa occurring naturally in South Africa, Namibia, Botswana, Zimbabwe, Mozambique, Zambia and Malawi. There has been little work on investigating the relationships between wild and cultivated forms, and to study amount and partitioning of genetic variation, to allow for better conservation strategies. This paper therefore is an attempt to summarise the work that has been done so far and the background literature, while providing the scope for the PhD study
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| 7. |
- Mujaju, Claid, et al.
(författare)
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Genetic diversity among and within watermelon (Citrullus lanatus) landraces in Southern Africa
- 2011
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Ingår i: Journal of Horticultural Science and Biotechnology. - : Informa UK Limited. - 1462-0316 .- 2380-4084. ; 86, s. 353-358
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Tidskriftsartikel (refereegranskat)abstract
- Genetic diversity in watermelon (Citrullus lanatus) was estimated among 213 seedlings from 22 accessions collected in Botswana, Namibia, South Africa, Zambia, and Zimbabwe. The accessions consisted of two types of watermelon landraces: sweet watermelon (C. lanatus var. lanatus) and cow-melon (C. lanatus var. citroides), also known as citron melon. In addition, three commercial varieties of C. lanatus var. lanatus from the USA were included for comparison. Ten simple sequence repeat (SSR; microsatellite) loci detected a total of 153 alleles. The polymorphic information content (PIC) ranged from 0.833 - 0.963, suggesting sufficient discriminatory power. Both a cluster analysis and a principal co-ordinate analysis produced two major clusters, one with the 13 cow-melon accessions and the other with the 12 sweet watermelon accessions. Within the sweet watermelon cluster, the three US cultivars grouped together with the Botswana accessions. Some of the other accessions also grouped according to their country of origin, but others did not. Within-accession diversity parameters showed that those sweet watermelon accessions found in traditional agrosystems were just as genetically variable as the cow-melon accessions.
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| 8. |
- 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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| 9. |
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| 10. |
- Mujaju, Claid, et al.
(författare)
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Molecular and farmer-based comparison of a wild-weed and landrace complex of watermelon in Zimbabwe
- 2012
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Ingår i: Australian Journal Of Crop Science. - 1835-2693 .- 1835-2707. ; 6, s. 656-661
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Tidskriftsartikel (refereegranskat)abstract
- Traditional farming systems have been associated with the occurrence of intervarietal and interspecific natural crosses in many crop plants, thus contributing to the genetic diversity of the crop through genetic exchange. In this study, a combination of farmerpreferred morphological traits and RAPD markers were used to evaluate the dynamics of genetic diversity in 43 watermelon accessions collected at a single village level with a traditional farming system. The molecular variability assessed with RAPD markers and analyzed with multidimensional scaling and cluster analysis, demonstrated a substantial differentiation among the accessions. Population structure analysis also demonstrated the existence of three major forms of watermelon, identified by a set of alleles predominant within each form. Dendrograms based on RAPD data and on farmer-preferred traits data were positively correlated according to a Mantel test. Although cultivated cow-melons were genetically most similar to wild-weedy plants at molecular level, they grouped more similar to sweet watermelons based on farmer-preferred traits. The present study revealed limited gene flow between three forms of watermelon and provides insight into how the genetic differentiation corresponds to farmers’ classification of watermelons
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