32 research outputs found

    Genetic diversity of Uapaca kirkiana Muel. Årg. populations as revealed by amplified fragment length polymorphisms (AFLPs)

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    Uapaca kirkiana is a priority fruit tree species for domestication in miombo woodlands of Southern Africa. Natural populations of U. kirkiana are declining through out the woodlands due to deforestation, forest fragmentation and wildfires. Knowledge of population structure and genetic diversity is prerequisite for development of conservation strategies. Amplified fragment length polymorphisms (AFLP) were used to assess the genetic diversity of eight populations from three geographical regionsof Malawi. AFLP markers revealed moderate differentiation (GST =0.079) among the populations collected from the three regions, however, there were no significant genetic variations among the regional collections. Analyses of molecular variance (AMOVA) found very high variation (92%) among individuals within populations and 6.8% among populations. The variations between populations indicate that populations can not be considered a single panmictic unit. Analyses of genetic similaritybased on unweighted pair group method of arithmetic averages (UPGMA) suggested that the 8 populations fall into three clusters with 5 populations in one cluster, two in another and the lake shore population of Chesamu in its own cluster. Based on results presented it would be cost effective tosample a small number of populations represented by a large number of individuals for germplasm conservation purposes. In view of the wide distribution of U. kirkiana in the miombo woodlands in Southern Africa there is need for a more intensive genetic study to include populations growing in different countries to produce a wider picture of levels of distribution of genetic diversity of the specie

    Indigenous knowledge of rural communities in Malawi on socio-economic use, propagation, biology, biodiversity and ecology of Uapaca kirkiana Muell. Arg

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    Uapaca kirkiana Muell Arg. is one of the most popular indigenous fruit trees in the Miombo woodlands of southern Africa. An investigation into existing indigenous knowledge and socio- economic use ofthis fruit tree was conducted in Malawi. The survey revealed that U. kirkiana fruits contribute considerably to livelihood as a food supplement and for income generation among local communities.However, U. kirkiana trees are not widely cultivated due to lack of improved planting materials and difficulties in establishment outside their natural habitats. The results from the survey indicate thatfruits are the main non-timber products that contribute to demand for domestication and the attributes preferred by the rural communities for improvement are mainly related to fruit taste and yield. Poormanagement and anthropogenic activities have resulted in the destruction of forest reserves and the local people do not have maximum stewardship of U. kirkiana trees in the forest reserve. Theindigenous knowledge on U. kirkiana trees provides a valuable basis for domestication, propagation and improvement of fruit and tree attributes, and management issues on both co-managed and government forest reserve

    Application of amplified fragment length polymorphism (AFLPs) for detection of sex–specific markers in dioecious Uapaca kirkiana Muell. Årg.

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    Uapaca kirkiana Muell. Årg is a dioecious fruit tree species for priority domestication in Southern Africa. It reaches reproductive maturity in eight to ten years with male plants making up 50% of breeding populations. Early identification of sex of seedlings is a prerequisite for selection and tree improvement. The amplified fragment length polymorphism (AFLP) technique was used to amplify DNAsegments of U. kirkiana male and female plants to identify sex-specific markers. A total of 84 selective primer combinations were screened using bulked segregant analysis (BSA) for males and females.More than 110 polymorphic markers were obtained but each of the four primer pairs (E-ACT/M-CTG, EACA/ M-CAA, E41+A/M-CTA and E-AGG/M-CTC) showed one band that was linked to sex. When the fourprimer pairs were tested in ten individuals from different populations only one primer pair (E-ACT/MCTG) amplified a 320 bp band in female plants only. It is possible that this marker is linked to a sexdetermininglocus. The results suggest that the gene that determines sex of U. kirkiana is autosomal in nature and this marker may be important during fruit domestication and tree improvement programmes. The marker has been sequenced and sequence characterised amplified region (SCAR) marker will be developed and used for precise and rapid identification of female plants

    Chromosome characterization and variability in some Iridaceae from Northeastern Brazil

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    The chromosomes of 15 species of Iridaceae of the genera Alophia, Cipura, Eleutherine, Neomarica and Trimezia (subfamily Iridoideae) were examined after conventional Giemsa staining. The karyotypes of Alophia drummondii (2n = 14+1B, 28, 42 and 56), Cipura paludosa (2n = 14), C. xanthomelas (2n = 28) and Eleutherine bulbosa (2n = 12) were asymmetric; Neomarica candida, N. caerulea, N. humilis, N. glauca, N. gracilis, N. northiana and Neomarica sp. (2n = 18); N. cf. paradoxa (2n = 28), Trimezia fosteriana (2n = 52), T. martinicensis (2n = 54) and T. connata (2n = 82) were all generally symmetric. New diploid numbers of 2n = 56 for Alophia drummondii, 2n = 18 for N. candida, N. humilis, N. glauca, and N. gracilis, 2n = 28 for N. cf. paradoxa, and 2n = 82 for T. connata are reported. The karyotypic evolution of the studied species is discussed

    HYACINTHACEAE

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    THE GENERIC DELIMITATION WITHIN HYACINTHACEAE. A COMMENT ON WORKS BY F. SPET
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