Species limits in Cannomois virgata complex (Restionaceae)

Bibliography: leaves 81-91.The variation in the nut morphology, floral and inflorescence morphology, culm morphology and culm anatomy of the Cannomois virgata complex are described. It is shown that this variation is best expressed by recognising three main clusters: the NW-Swartberg, aledonLangeberg and Coastal. The existence of these clusters was largely influenced by the size of the nuts, bracts, perianths and hollow cavity to culm diameter ratio. These traits were congruent with the overall morphometric variation, shown by the results of the phonetic analysis. The clusters correspond to three species proposed under the operational definition, which recognises species from differentiated clusters in phenetic space whose distinctness was assumed to be the manifestation of underlying fixed and qualitative differences following speciation. These units were considered appropriate as terminals for phylogenetic reconstruction. Empirical comparison of six prevailing species concepts was made by taking advantage of a common operational exigency i.e., the use of phenotypically irreducible clusters of individuals as first order estimates of species. Also, diagnostic characters were found in each of the clusters indicating the existence ofa species complex, rather than a single taxon. I therefore propose that the name Cannomois virgata (Rottb.) Steud. be restricted to the individuals of the Coastal group from which the type was collected. A new species, Cannomois grandis Mujaju, is proposed for the plants belonging to the Caledon-Langeberg group, owing to the giant form exhibited by these plants which are 2 to 3.5 metres tall. The name, Cannomois saundersii Mujaju, was proposed for the NW -Swartberg, in recognition of Mr. Saunders, a seed collector. The distribution of the species were related to the cladogram, suggesting that speciation may have been sympatric for all taxa or somewhat allopatric as shown by the NW -Swartberg taxon which has an overall northern inland distribution within the Cape Floral Region in comparison with the other two

Do smallholder farmer-led seed systems have the capacity to supply good-quality, fungal-free sorghum seed?

Local seed systems that are developed, managed and maintained by farmers are a fundamental practice in smallholder crop production, supporting more than 80% of farmers in sub-Saharan Africa and feeding more than 70% of its population. The resilience of such systems is under threat from poverty, climate change, drought, increased pests and diseases, over-promotion of modern crop varieties, change of lifestyles and restrictive seed policies. The system continues to be maligned as having inferior quality, yet few studies support this assertion. This study aims to fll this research gap by evaluating 60 sorghum seed samples collected from smallholder farmers in Uzumba-MarambaPfungwe and Chimanimani districts of Zimbabwe. We investigated the efect of farmer-led seed management practices (e.g. seed acquisition and seed storage practices) on farm-derived sorghum seed quality (moisture, germination and fungal incidences). We found farmers using diverse seed sources and seed storage practices. Seeds were typically of good quality in that their storage moisture content was low, their germination was high, and fungal incidences were low. Seed sourced from local markets, non-governmental organizations and other farmers had germination and moisture standards that met the sorghum certifcation standards in Zimbabwe. However, few samples obtained from the relatives and government failed to meet the germination and/or moisture certifcation standards. We detected low incidences of fungi (Aspergillus favus, Aspergillus niger, Curvularia lunata, Fusarium sp. and Penicillium sp.) in sorghum seed samples tested and in particular Fusarium sp., which is the most economic important fungus in sorghum production. We conclude that farmer-led seed systems have the capacity to supply seeds of good quality and recommend that such systems should be recognized and promoted to meet the ever-evolving needs of smallholder farmers in sub-Saharan Africa

Advances in the registration of farmers’ varieties: Four cases from the global South

Over the last few decades, there has been a growing appreciation of crop varieties developed by local farmers, commonly referred to as farmers’ varieties. These varieties often have attractive characteristics for both producers and consumers, such as adaptability to harsh environmental conditions and high nutritional values. Yet they are usually not sold in formal markets, and tend to be limited to farmers’ seed systems. This is partially due to national seed laws that, in an effort to guarantee good quality seed of uniform and stable varieties, create obstacles for farmers’ varieties to reach the market. This article describes the experiences of four countries—Bolivia, Laos, Nepal and Zimbabwe—that are developing alternative variety registration systems for farmers’ varieties. Most of these cases have never been documented before. The cases present the main drivers behind and approaches to the registration of farmers’ varieties in different legal contexts and at different stages of development. We conclude that farmers’ variety registration systems can generate benefits including faster and cheaper variety releases, improved farmer incomes, and a larger diversity of well-adapted varieties in the market—but some important issues are still to be resolved

Diversity of landraces and wild forms of watermelon (Citrullus lanatus) in southern Africa

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

Diversity of landraces and wild forms of watermelon (Citrullus lanatus)

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

The effect of using inorganic and cattle manure with different top-dressing rates of ammonium nitrate on yield of maize under wetland conditions

Abstract,Smallholder farmers are facing problems of low soil fertility causing maize yield reduction of up to 1.5 tonnes per hectare (t/ha) compared to 5 t/ha obtained in the commercial sector. A maize trial was conducted on two wetlands in Natural Region IV of Zimbabwe at Zungwi vlei to determine effects of different rates of compound D and cattle manure as basal dressing with different rates of ammonium nitrate as top-dressing. The maize used was a two-way early maturing hybrid developed by Seed Co. (SC513) for marginal areas. Four basal applications were applied in the trial as treatments for two seasons with four different levels of nitrogen applied as subplots factor. The analysis revealed a highest significant increase in grain yield when 300 kilogrammes per hectare (kg/ha) of compound D was applied with 150 kg/ha of ammonium nitrate (N) as top-dressing. Significant increase in grain yield was also observed when cattle manure was applied with 150 kg/ha top-dressing of N. There was a significant yield advantage when the nitrogen was increased after applying a basal dressing in both sites for the two seasons. In order to achieve high yields, the use of compound D at 300 kg/ha as basal dressing and top-dressing at 150 kg/ha N is highly recommended to farmers. However, for the lowresourced and poor farmers, the use of cattle manure which is generally cheaper and affordable is recommended

Phenotypic Diversity of Date Palm Cultivars (Phoenix dactylifera L.) from Sudan Estimated by Vegetative and Fruit Characteristics

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

Variationsrika vattenmeloner i södra Afrika

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 grönsake

The effect of using inorganic and cattle manure with different top-dressing rates of ammonium nitrate on yield of maize under wetland conditions

AbstractSmallholder farmers are facing problems of low soil fertility causing maize yield reduction of up to 1.5 tonnes per hectare (t/ha) compared to 5 t/ha obtained in the commercial sector. A maize trial was conducted on two wetlands in Natural Region IV of Zimbabwe at Zungwi vlei to determine effects of different rates of compound D and cattle manure as basal dressing with different rates of ammonium nitrate as top-dressing. The maize used was a two-way early maturing hybrid developed by Seed Co. (SC513) for marginal areas. Four basal applications were applied in the trial as treatments for two seasons with four different levels of nitrogen applied as subplots factor. The analysis revealed a highest significant increase in grain yield when 300 kilogrammes per hectare (kg/ha) of compound D was applied with 150 kg/ha of ammonium nitrate (N) as top-dressing. Significant increase in grain yield was also observed when cattle manure was applied with 150 kg/ha top-dressing of N. There was a significant yield advantage when the nitrogen was increased after applying a basal dressing in both sites for the two seasons. In order to achieve high yields, the use of compound D at 300 kg/ha as basal dressing and top-dressing at 150 kg/ha N is highly recommended to farmers. However, for the lowresourced and poor farmers, the use of cattle manure which is generally cheaper and affordable is recommended

Genetic diversity in Swedish and Finnish heirloom apple cultivars revealed with SSR markers

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