Extensive research has been conducted on the characterization of hundreds of date palm (Phoenix dactylifera L.) cultivars worldwide. However, the population genetics of date palms has never been studied. In this study, we collected 200 individuals from 19 populations of different geographical locations in Sudan. The collection sites were grouped according to the type of dates (date palm fruits) that dominates in the area. Ten microsatellite markers were used to investigate the genetic diversity within and among populations and the correlation between the genetic and geographical distances. The tested microsatellite markers showed a high level of polymorphism. A total of 261 alleles were detected at the ten loci. The overall mean value of fixation indices equalled − 0.163, which shows the presence of excess heterozygosity. However, the χ2 tests conducted for every locus in each population indicated no significant deviation from the Hardy–Weinberg equilibrium. The analyses of molecular variance exhibited that about 95% of the total genetic variation existed within populations, while significant differentiation within the type groups could be detected. Although significant isolation by distance (r2 = 0.552, P < 0.05) was detected by a Mantel test, it seems that the spatial effect has become complicated as a result from the exchange and introduction of different kinds of plant materials by date palm growers and traders, as well as seed dispersal. This complexity was clearly apparent in the weak clustering relationships among most of the tested populations.

The conservation of crop genetic resources is an international priority and requires the continued collection and characterization of farmer varieties. We collected and characterized maize and upland rice populations cropped by farmers in Panama's Azuero region. The objective of our study was to evaluate the crop genetic diversity of farmer varieties of maize and upland rice grown by poor farmers in Panama. We found that: (1) farmers' naming practices only partially corresponded to genetic relationships and were the strongest for rice populations; (2) farmers' classification of populations as ‘modern’ or ‘traditional’ was reflected in phenotypic differences; (3) Panamanian maize populations were molecularly distinct from populations collected elsewhere in Latin America; and (4) heterogeneous rice populations were common and heterogeneity was often due to admixture of recognized farmer varieties. Our results indicate that poor farmers in Panama continue to farm ‘traditional’ varieties that harbour genetic diversity of interest. There has, however, been substantial adoption of ‘modern’ varieties.

Wild relatives of pigeonpea (Cajanus cajan L.) possess many useful genes that can be utilized for crop improvement, most importantly genes for resistance to Helicoverpa armigera, the legume pod borer. The present study aimed at quantifying diversity in a collection of Cajanus scarabaeoides, Cajanus sericeus, Cajanus reticulatus and C. cajan species selected from a wide geographic range using two PCR-based marker systems, amplified fragment length polymorphism (AFLP) and simple sequence repeats (SSRs), and the hybridization-based restriction fragment length polymorphism (RFLP). Polymorphism was higher among the wild accessions than among the cultivated genotypes. Wild and cultivated Cajanus accessions belonging to different species clustered into four distinct major groups largely based on the interspecific differences. C. scarabaeoides accessions derived from same geographical origins formed one group reflecting similar genetic makeup of these accessions. Dendrograms generated using AFLP, RFLP and SSR marker data were comparable with minor clustering differences, which suggests that either method, or a combination of both can be applied to expanded genetic studies in Cajanus. Mantel testing confirmed the congruence between the genetic distances of three markers, indicating that the markers segregated independently, giving similar grouping patterns of all accessions having similar genetic origin.

Nineteen kenaf genotypes from Cuba, Taiwan, the USA, El Salvador, Guatemala, Russia, Spain and Indonesia, and three wild types collected in South Africa were analysed for genetic diversity using AFLP analysis. All could be uniquely distinguished from one another, but only a low level of genetic diversity was present. The most distinct accession, Guatemala 4, was 85% similar to all other accessions. The accessions clustered more or less according to known pedigree and/or origin. Two of the three wild types (Hibiscus cannabinus c and H. cannabinus a) clustered separately from the commercial and Russian accessions. One of the wild types, H. cannabinus b clustered with some of the commercial accessions. Commercial accessions in the first subgroup all originated from central and North America, and surrounding islands (Cuba and El Salvador). The Russian accessions are all grouped together. The second subgroup was the only group that contained accessions from different geographical origins.

Thirty-eight melon accessions, which are of primary breeding importance in the Ukraine, were analysed for diversity. These collections represent a major non-US and non-western Europe source of melon germplasm that have not yet been subjected to molecular characterization. Molecular diversity was estimated based on a robust set of 465 polymorphisms gathered by amplified fragment length polymorphisms and simple sequence repeats (SSR). In this paper, we report 12 newly developed polymorphic SSR primer pairs, and their use for molecular characterization in the Ukrainian melon collections. Based on these polymorphisms, we estimated similarity indices that ranged from 0.70 to 1.00 among various accessions. The phylogenetic tree based on the similarity indices and a three-dimensional plot of the first three vectors of the principal component analysis corresponded fairly well with the existing three classical morphotypes namely aestivalis, europeus and hiemalis, under the convarEuropeus, which is also known as adana. The polymorphisms generated in the current study, which are specific to the grouping of fruit types and days to maturity will be very useful for further genetic studies and marker-assisted selections.

Characterization and genotype identification are essential for rational conservation, management and genetic diversity evaluation. In this work, simple sequence repeat (SSR) markers were used to identify 57 accessions of sweet potato kept at the ‘in vitro’ Gene Bank of INTA, Argentina. This collection includes primitive materials from primary zones of dispersion, commercial varieties, breeding clones and foreign materials from different parts of the world (Africa, Asia and USA). Average similarity between the materials evaluated was 0.367. Grouping analysis revealed six clusters and a strong association with skin colour of storage roots. The set of selected SSR markers allowed us to verify identity, detect duplicates and estimate the genetic similarity of the materials analysed. This characterization complements morphological data and provides tools to estimate the variation of diversity between local and foreign germplasm groups.

Tobacco germplasm are of different ‘types’, with large numbers of accessions in each type. In order to effectively manage this tobacco germplasm information, a user-friendly menu-driven software has been developed based on Visual C++ and MS-Access. The system allows the user to store, modify and update germplasm information as and when required, and represents a decision-making tool.

The purpose of this study is to identify key home garden species in order to address basic research questions aimed at understanding farmers' home gardens management practices. The study was conducted in two contrasting Hill and Tarai sites in Nepal with households (HHs) ranging from 355 to 634. Unlike larger production systems, home gardens harbour many species in small areas often with a few crop varieties and species that are not well represented in larger fields. Given the number of species and their small population sizes, species and genetic diversity are best studied by identifying representative key species characterizing the complex productive niches within farms. Although species diversity within community is large (172–342), 24 key species were identified for the study. There is no fixed size of a home garden. The log of home garden size and species richness was positively correlated (r = 0.42, P < 0.001). Species richness was significantly higher in vegetable followed by fodder, fruits and spices. This paper also explores the diversity in home gardens to identify the composition and characteristics of the key species and how they are managed, used and conserved. Most of the farmers save the seeds of these home garden species for their own use, but many also exchange and buy and sell seed in local weekly market. Farmers' practices for selecting seed vary according to the reproductive biology of the key home garden species. Home gardens provide the HH with fresh and diverse supply of nutritious food, which improves their self-sufficiency, while conserving diversity on-farm. Despite this, they are neglected in research and development by policy makers and researchers.

In Ethiopia, barley is used to make various types of foods, and home-made and industrial beverages. The various kinds of end-use of barley grain by rural people in two districts of West Shewa are reported. According to farmers, no other cereal crop can be processed into so many different forms of food. At least 17 kinds of foods and beverages, which are consumed in the form of whole-grain snacks, sauces, soups, drinks and baked foods, were reported. Some are mainly served on special occasions like annual ceremonies and cultural gatherings, while others are served as main dishes. Black- and purple-grained barleys are preferred for malting and home-made alcoholic drinks, whereas white-grained types are used for baking and roasting. Each landrace has its own inherent property that makes it suitable for at least one end-use. Since ancient times, barley foods are also known to farmers as remedies and traditional medicines for many kinds of diseases. The various kinds of utilizations of barley and its value in the socio-cultural lifestyles of farmers play vital roles for the on-farm maintenance of different landraces in West Shewa.

Changes in global biodiversity at the genetic level have proved difficult to determine for most organisms because of lack of standardized, repeated or historical data; this hampers the attempts to meet the convention on biological diversity (CBD) 2010 targets of reducing loss of genetic diversity, particularly of crop species. For rice, where germplasm and genetic data have been collected throughout South and Southeast Asia over many decades, contrary to popular opinion, we have been unable to detect a significant reduction of available genetic diversity in our study material. This absence of a decline may be viewed positively; over the 33-year timescale of our study, genetic diversity amongst landraces grown in traditional agricultural systems was still sufficiently abundant to be collected for ex situ conservation. However, if significant genetic erosion does take place in the future as a result of accelerating global warming and/or major changes in land use or agricultural practices, will it be catastrophic or gradual, and how will it be detected? We have shown a strong link between numbers of landraces collected (and therefore extant) and genetic diversity; hence, we have a clear indicator to detect loss of genetic diversity in the future. Our findings lend considerable support for ex situ conservation of germplasm; the more than substantial genetic resources already in genebanks are now safe. On the other hand, it is the germplasm growing in farmers' fields, continually adapting genetically to changing environmental conditions and evolving novel genetic forms, whose future has been much less certain but can now be effectively monitored using our criteria.

To assess the genetic diversity among Tunisian local barley, a set of 120 barley accessions representing five distinct geographical regions (North-West, Littoral, South, Jerba and Kerkennah Islands) was characterized with 20 simple sequence repeats (SSR) and 8 expressed sequence tag (EST)-SSR markers. The 28 loci revealed a total of 98 alleles, with an average of 3.76 alleles per locus (range 2–10). Gene diversity averaged 0.50 (range 0.09–0.84). Partitioning analysis of genetic diversity showed that about 95% of the total variation was within regions and no geographical differentiation could be found except for the North-West population. Similarly, neighbour joining clustering of the genotypes did not indicate any clear pattern of division among the barley accessions based on geographical origin. These results may reflect the impact of seed exchange between farmers which is likely to limit highlighting favourable alleles due to local adaptation.

Foxtail millet (Setaria italica (L.) Beauv.) is one of the ten small millets and is cultivated in 23 countries. The foxtail millet is valued as a crop of short duration, which is good as food, feed and fodder. In general, grain yield levels of foxtail millet are low in comparison with other staple cereals. The greater use of diverse germplasm in breeding is suggested as a means to improve the productivity of this crop. The International Crops Research Institute for the Semi-Arid Tropics genebank is presently holding 1474 cultivated germplasm accessions from 23 countries. To utilize this diversity in research, a core collection (10% of the entire collection) was established using the taxonomic and qualitative traits data. The germplasm accessions were stratified into three taxonomic races (Indica, Maxima and Moharia). Principal coordinate analysis was performed on 12 qualitative traits for each of the biological races, separately that resulted in the formation of 29 clusters. From each cluster, 10% of the accessions were selected to constitute a core collection of 155 accessions. The composition and diversity of the core collection was validated by the χ2-tests of the frequencies of origin, races, subraces and data on qualitative traits. The analysis of the quantitative traits for mean, range, variance, Shannon–Weaver diversity index and phenotypic associations indicated that the diversity from the entire collection was optimally represented in the core collection. The core subset will be evaluated in replicated trials to make a more precise assessment of diversity and further efforts to identify the sources of agronomic and grain nutritional traits for utilization in breeding programmes.

Many crop genetic resources collections have been established without a clearly defined conservation goal or mandate, which has resulted in collections of considerable size, unbalanced composition and high levels of duplication. Attempts to improve the composition of collections are hampered by the fact that conceptual views to optimize collection composition are very rare. An optimization strategy is proposed herein, which largely builds on the concepts of core collection and core selection. The proposed strategy relies on hierarchically structuring the crop gene pool and assigning a relative importance to each of its different components. Comparison of the resulting optimized distribution of the number of accessions with the actual distribution allows identification of under- and over-representation within a collection. Application of this strategy is illustrated by an example using potato. The proposed optimization strategy is applicable not only to individual genebanks, but also to consortia of cooperating genebanks, which makes it relevant for ongoing activities within projects that aim at sharing responsibilities among institutions on the basis of rational conservation, such as a European genebank integrated system and the global cacao genetic resources network CacaoNet.

Date palm fruits of 15 cultivars were collected at harvest (Tamr stage) from the Nori Horticultural Orchard in the Northern State of Sudan for morphological and chemical characterization. Morphological and DNA polymorphisms of the mother trees were also investigated. Significant (P < 0.001) differentiation of cultivars in relation to tree height, and number and length of pinnae and spines was observed. Fruit weight, flesh weight and fruit and seed sizes expressed a wide range of diversity among cultivars. Significant differences were also observed among cultivars for all tested sugars (P < 0.001). Titratable acidity was found to be a characteristic feature of almost every cultivar. The results of DNA genotyping indicated high genetic diversity among cultivars with Nei's genetic distances ranging from 0.693 to 3.496, and expected and observed heterozygosity equalling 0.837 and 0.950, respectively. This study highlights the diversity of date palms in Sudan, as represented by apparent morphological characters, chemical composition of fruits as well as DNA polymorphism. The employment of different techniques for data analyses gave conclusive ideas on some interrelationships among a large set of characters; the knowledge of such relationships can be utilized for screening date palm cultivars for possible descriptors.