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The objective of this study was to examine the shoot formationcapacity of the capitulum explants of some gerbera cultivars in differentnutrient media. Immature capitulum explants of the gerbera cultivarsAmeretto, Red Bull, Ruby Red and Yanara were cultured on Pierikmedium (P) with different concentrations of benzyladenine (BA) andRadice and Marconi medium (RM). The main P and RM media were usedeither in liquid form using cotton wool as support or solidified with agar.There was a significant interaction between the different media and thegerbera cultivars in all the parameters measured. The gerbera cultivarsshowed different responses to various media compositions with regard toshoot formation on the capitulum explant.There was a general increase invitrification rate with the increase in the BA concentration in the medium.Shoots formed in liquid media showed a high vitrification rate.

An experiment was conducted to study the effect of cultivar andconcentration of agar and gelrite on in vitro multiplication of gerbera(G.jamesonii) shoots. Sterile in vitro growing shoots of the gerbera cultivarsAmeretto, Red Bull, Ruby Red, Yellowish green and Crillo were placed inglass jars containing nutrient media with different concentrations of agar andgelrite. There was a significant interaction between the gelling agents’concentrations and the gerbera cultivars. There was a decrease in themultiplication and vitrification rates with the increase of the concentration ofthe different gelling agents in the nutrient medium.

This study was conducted to investigate the effect of somegrowth regulators on in vitro shoot regeneration, multiplication androoting of Chrysanthemum morifolium to develop a protocol for its masspropagation. Nodal explants of C. morifolium were cultured on MS basalmedium supplemented with the cytokinins BAP and kinetin, both at 0.0,0.1, 0.2, 0.5, 1.0, 2.0, 5.0, 10.0 mg/l, for shoot regeneration. Theregenerated shoots were separated from the nodal explants and culturedon MS medium supplemented with BAP and kinetin, both at 0.0, 0.1, 0.2,0.5 mg/l for shoot multiplication. The shoots were then cultured on MSmedium supplemented with 0.0, 0.1, 0.2, 0.5 mg/l of IBA for rooting.Twenty explants were used per treatment. The percentage of respondedexplants, average number of shoots per explant, length of shoot,percentage of rooted shoots, number of roots per shoot and length of rootwere determined. The concentration of 0.1 mg/l of both BAP and kinetinshowed the best response with regard to shoot regeneration andmultiplication giving the highest number of shoots per explant.Cytokinin–free medium gave significantly the highest length of shoot. AllIBA treatments gave 100% rooting. However, MS+ 0.5 mg/l IBA resultedin significantly the highest number of roots per shoot, and IBA–freemedium resulted in significantly the highest root length

The objective of this study was to investigate the effect of the cytokinins benzylaminopurine (BAP) and Kinetin on in vitro shootregeneration on shoot tips of Polyscias balfouriana marginata. Shoot tips were cultured on Murashige and Skooge (1962) medium (MS) supplemented with various concentrations of BAP and Kinetin at 0.0, 0.75, 1.5, 3, 6 mg/L for both. Results showed that Polyscias balfouriana marginata responded positively to growth regulators application and there was significantdifference among concentration treatments. The highest percentage of responded explants was given by BAP and Kinetin - free medium and the one containing the lowest concentration of both (0.75 mg/L). The concentration 3 mg/L BAP showed significantly the highest number of shoots/explant. There was no significant difference between kinetin concentratios 0.75 and 1.5mg/L, yet they resulted in significantlys higher number of shoots/explant compared to the control.The concentration 0.75 mg/L of both BAP and kinetin recorded the highest shoot length while the shortest shoot resulted from 6 mg/L of both cytokinins and the control of kinetin.

UNLABELLED • PREMISE OF THE STUDY Adansonia digitata L. is one of the most important indigenous fruit trees of mainland Africa. Despite its significance for subsistence and income generation of local communities, little is known about the genetic and morphological variability of East African populations of A. digitata, including those of Sudan. The aim of the current study, therefore, was to analyze genetic and morphological variability of different baobab populations in Kordofan, Sudan and to estimate the effect of human intervention on genetic differentiation and diversity.• METHODS A total of 306 trees were randomly sampled from seven spatially separated locations in the Nuba Mountains, Sudan, to cover a wide range of differing environmental gradients and management regimes ('homesteads' and 'wild'). Genetic analyses were conducted using nine microsatellite markers. Because of the tetraploid nature of A. digitata, different approaches were applied to estimate patterns of genetic diversity. Investigations were completed by measurements of dendrometric and fruit morphological characters.• KEY RESULTS Genetic diversity was balanced and did not differ between locations or management regimes, although tendencies of higher diversity in 'homesteads' were observed. A Bayesian cluster approach detected two distinct gene pools in the sample set, mainly caused by one highly diverse population close to a main road. The variability of tree characters and fruit morphometries was high, and significantly different between locations.• CONCLUSIONS Results indicated a rather positive effect with human intervention. The observed populations provide a promising gene pool and likely comprise ecotypes well-adapted to environmental conditions at the northern distribution range of the species, which should be considered in conservation and management programs.

Traditional homegardens (HGs) are considered to harbor high levels of plant diversity and have been therefore characterized as sustainable agro-ecosystems suitable for on-farm (incl. circa situm) conservation of plant genetic resources. While the functional structure of traditional HGs is poorly understood specifically for semi-arid and arid regions, their plant species richness and diversity is increasingly threatened by recent and fast evolving agricultural transformation processes. This has been particularly claimed for traditional jubraka HG systems of Sudan. Therefore, sixty-one HGs in four villages of the Nuba Mountains, South-Kordofan Province, Sudan, were randomly selected, geographically recorded and plant richness and abundance determined and plant diversity parameters calculated. In addition, socio-economic household data were assessed by interviews and soil samples taken to allow a comprehensive analysis of putative factors affecting HG plant diversity across different villages, levels of commercialization and plant species composition based clusters. A total of 110 species from 35 plant families were grown in the HGs along with 71 ornamentals. Perennial species accounted for 57 % including 12 indigenous fruit tree (IFT) species and six exotic fruit tree species. Mean species richness of useful plant species (excluding ornamentals) per HG was 23 (range 6–46). On average, 41 % of the 23 species per HG were of exotic origin, however, with a large range (21–83 %) among locations. Mean diversity and evenness indices were 1.46 (range 0.49–2.42) and 0.48 (0.15–0.87), respectively. The level of commercialization of HGs only marginally affected species diversity measures although the species richness was significantly higher for commercial than subsistence HGs. Species richness was higher on lower (6.6–7.2) pH soils. IFT richness was highly variable, but non-significantly different across the four locations. Plant species richness and diversity was high in comparison with other HG systems in semi-arid regions. Cluster analysis was found to be a valuable tool to classify HGs and to extract homogeneous HG types with low, intermediate and high richness and diversity. In addition, the share of exotic and ornamental species in HGs indicated a trend towards the loss of traditional farming practices, particularly in areas with good market access. The data did not indicate the hypothesized loss of inter-specific diversity due to commercialization and species richness was numerically even higher for market-oriented HGs compared to subsistence ones.

Iterative domestication processes by humans such as selection, translocation and cultivation are known to affect the morphological and genetic diversity of tree species. Since many of these species occur also in human-created homegardens (HG) this type of agroecosystem therefore represents an ideal setting to study such domestication processes. The threatened indigenous fruit tree Ziziphus spina-christi occurs in HGs and forests of the Nuba Mountains, Sudan, and was therefore selected as a model species. Five locations were sampled and the geographical position of 250 trees determined. Each location was subdivided into HG and forest sites. The diversities of morphological traits and amplified fragment length polymorphisms were assessed to study variation within and among locations and sites. Diversity of dendrometric parameters and fruit morphometries was high and differed significantly among locations. Environmental parameters affected dendrometry and fruit size, but applied regression models were of low explanatory power. Although statistically not significant, mean fruit measures were continuously larger in HGs than in forests. Higher genetic diversity was observed in HG samples. Larger dendrometric and fruit morphometric traits are likely to result from better growing conditions in HGs and/or human selection of germplasm. This is in line with the higher genetic diversity in HGs which may be a consequence of the admixture of germplasm from different origins planted in HGs. Z. spina-christi underwent incipient steps of domestication. High genetic diversity in HGs suggests those as valuable spots of improved germplasm and for on-farm conservation purposes.