Extensive collections of lentil germplasm now exist in various genebanks around the world. This germplasm including wild Lens species has been used in plant introduction strategies and in efforts to widen the potential sources of increasing genetic diversity in the breeding programmes of lentil. Improved techniques are emerging to overcome hybridization barriers between species and as a result, interspecific hybrids have been successfully obtained between species. Several interspecific recombinant inbred line populations have been developed. Selected and backcrossed lentil lines are currently in advanced yield trial stages, and desirable traits such as yield, disease resistance and agronomic traits have been incorporated into cultivated lentil especially from Lens ervoides, generating a wider spectrum of variability. Secondly, further expansion of the overall pool of germplasm and examination of allelic variation at the nucleotide level will benefit lentil-breeding programmes by augmenting phenotype-based variation to further advance cultivar development. Genomic resources for lentil are limited now, but this situation is changing rapidly as the cost of genotyping has declined. As a result, two successive expressed sequence tags (EST) projects were undertaken under the NAPGEN EST project initiative (http://www.nrc-cnrc.gc.ca/eng/programs/pbi/plant-products/napgen/.htm) and an Agricultural Development Fund project initiative. We emphasize that creation of intraspecific and interspecific genetic populations, genetic maps, association maps, quantitative trait loci and marker-assisted selection technologies for implementation in the breeding programme will enhance deployment of genes responsible for traits of interest. The economical use of genomic technologies for use in germplasm resource management and genetic improvement is on the near horizon.

Conservation of crop germplasm diversity involves the establishment of in situ and ex situ genebanks. The major activities for ex situ genebanks include assembling, conserving, characterizing and providing easy access to germplasm for scientists. More than six million accessions are currently assembled in over 1300 genebanks worldwide. ICRISAT is one of the 15 CGIAR centres, with headquarters at Patancheru, India, and conserves genetic resources of sorghum, pearl millet, chickpea, pigeonpea, groundnut, and six small millets. The ICRISAT genebank holds 114,870 accessions from 130 countries, including both archival materials from various organizations throughout the world, and from fresh collections resulting from 213 missions in 62 countries. The ICRISAT genebank supplies annually over 40,000 germplasm samples to scientists worldwide. Sixty-six varieties selected from the basic germplasm have been released for cultivation in 44 countries, and ICRISAT has restored/repatriated crop germplasm to eight countries. The research focus is on germplasm diversity assessment, developing core and mini-core collections, and using a molecular characterization approach to both enhance the utilization of germplasm in research and improve the efficiency of germplasm management. Following these approaches, we have been able to identify a significant number of accessions with traits potentially relevant for crop improvement.

Cowpea is an important grain legume crop in sub-Saharan Africa (SSA) where, on a worldwide basis, the bulk is produced and consumed. The dry savanna area of SSA is where cowpea is mostly grown under rain-fed conditions. The crop is therefore prone to drought which may occur early, mid and/or late in the cropping season. Compared with many other crops, cowpea is drought tolerant, even though drought is still a major constraint limiting its productivity in SSA. Increasing the level of drought tolerance in existing cowpea varieties grown by farmers would enable them to obtain more and stable yield from their cowpea fields. As a first step towards enhancing drought tolerance in existing cowpea varieties, 1288 lines were selected randomly from cowpea germplasm collections maintained at the International Institute of Tropical Agriculture, and evaluated for their drought tolerance at Ibadan. Drought was imposed by withdrawal of irrigation from 5 weeks after sowing. On average, drought reduced the number of days to flower by 12 d, and the mean grain yield per plant was also reduced by 67.28%. A few of the cowpea lines stayed green for up to 6 weeks after irrigation was stopped, even though some of these produced no pods when the study was terminated. Further evaluation in the screenhouse of 142 selected drought-tolerant lines helped to identify six lines that could be potential parents for developing breeding lines with enhanced drought tolerance.

For maintaining food security and livelihood, farmers in marginal areas of production environments make use of high levels of crop genetic diversity. The exchange of seed and varieties among villagers, and also the relative isolation of local varieties in their production environments, contributes to the continued existence of locally adapted genotypes. In Tigray, one of the major barley-growing regions of Ethiopia, local varieties and local seed systems are dominant. The annual barley seed requirement is met with seed produced, saved and exchanged by farmers. In order to understand the flows of seed and varieties within and between villages, a study was conducted using a survey to gather information from 130 respondents in seven villages. Seed network analysis was used as an analytical tool to assess flows of seed and varieties and to identify farmers who play different roles in the seed system. Within the major seed exchange network, nodal or connector farmers linked seed subnetworks. The flow within villages was much more dominant than beyond. Rare varieties appeared to be sourced from farms that maintain a broad variety portfolio. Varieties seemed to disseminate informally across farms, in their target environments, following participatory varietal selection. The methodology of social seed network analysis proved to be a powerful tool for monitoring seed and variety flows. Furthermore, it identified farmers as critical partners in the conservation and on-farm management of plant genetic resources, recognized the role of plant breeders in participatory varietal selection and that of seed experts, engaged in strengthening local seed supply and in disseminating quality seed of superior varieties.

The valorization of genetic diversities of major crops like wheat may help substantially to feed the world Population. Durum wheat genotypes consisting of 265 farmers’ varieties (FVs), which have been cultivated for many centuries in Ethiopia, as well as 24 improved varieties (IMVs) have been recently evaluated in northern Ethiopia. The evaluation has been carried out at two different locations for 2 consecutive years to verify the inherited diversity in FVs for important phenological and agronomic traits; with the intention to provide refined information to breeders and genebank managers. As a result of a careful evaluation, a very significant variation was observed between the FVs and IMVs. A large number of the former have demonstrated superior performance to the latter in terms of mean values of the major traits within the stipulated years and locations. The best performing FV has shown a gain of 20% grain yield over the best IMV. Multivariate analyses revealed that FVs displayed larger genetic diversity than in those IMVs. FVs could therefore be used as donor of useful alleles in durum wheat breeding for improvement of yield per se and other traits of agronomic and phenological importance. The identified stable superior FVs include: 8208, 226834A, 238567, 222426, 226282 could be best candidates for farmers in marginal environments. Genotypes that have shown stable performance for spatial variation such as 204493A, 214357 and 238567; and temporal variation such as 8208, 208479, 214357 and 226834A could be the best candidates for exploitation in future breeding programs.

Olea europaea L. has been cultivated in the Mediterranean region for thousands of years and is of major economic importance. The origin of olive cultivars remains as complex to trace as their identification. Thus, their molecular characterization and discrimination will enable olive germplasm management. In addition, it would be a useful tool for authentication of olive products. High-resolution melting (HRM) analysis, coupled with five microsatellite markers, was integrated to facilitate molecular identification and characterization of main O. europaea cultivars collected from the National Olive Tree Germplasm Collection established in Chania, Greece. The five microsatellite loci used were highly informative and generated a unique melting curve profile for each of the 47 cultivars and for each microsatellite tested. In particular, three microsatellite markers (DCA03, DCA09 and DCA17), which generated 29 HRM profiles, were sufficient to genotype all the olive cultivars studied, highlighting their potential use for cultivar identification. Furthermore, this assay provided a flexible, cost-effective and closed-tube microsatellite genotyping method well suited for molecular characterization of olive cultivars.

There is a long-standing concern that modern plant breeding reduces crop genetic diversity, which may have consequences for the vulnerability of crops to changes in pests, diseases, climate and agricultural practices. Recent molecular assessments of genetic diversity changes in existing genepools of major agricultural crops may shed some light on the impact of plant breeding on crop genetic diversity. Reviewing published assessments revealed different impacts of plant breeding on improved genepools, not only narrowing or widening their genetic base, but also shifting their genetic background. In general, the genome-wide reduction of crop genetic diversity accompanying genetic improvement over time is minor, but allelic reduction at individual chromosomal segments is substantial. More efforts are needed to assess what proportion of lost alleles is associated with undesirable traits.

Pigeonpea (Cajanus cajan (L.) Millsp. is one of the most important legume crops as major source for proteins, minerals and vitamins, in addition to its multiple uses as food, feed, fuel, soil enricher, or soil binder, and in fencing, roofing and basket making. ICRISAT's genebank conserves 13,632 accessions of pigeonpea. The extensive use of few parents in crop improvement is contrary to the purpose of collecting a large number of germplasm accessions and has resulted in a narrow base of cultivars. ICRISAT, in collaboration with the Generation Challenge Program, has developed a composite collection of pigeonpea consisting of 1000 accessions representing the diversity of the entire germplasm collection. This included 146 accessions of mini core collection and other materials. Genotyping of the composite collection using 20 microsatellite or simple sequence repeat (SSR) markers separated wild and cultivated types in two broad groups. A reference set comprising 300 most diverse accessions has been selected based on SSR genotyping data. Phenotyping of the composite collection for 16 quantitative and 16 qualitative traits resulted in the identification of promising diverse accessions for the four important agronomic traits: early flowering (96 accessions), high number of pods (28), high 100-seed weight (88) and high seed yield/plant (49). These accessions hold potential for their utilization in pigeonpea breeding programmes to develop improved cultivars with a broad genetic base. Pigeonpea germplasm has provided sources of resistance to abiotic and biotic stresses and cytoplasmic-male sterility for utilization in breeding programmes.

Vicine and convicine are anti-nutritional compounds that accumulate in the cotyledons of faba beans. When humans consume beans with high levels of these compounds, it can cause a condition called favism in individuals harbouring a deficiency in the activity of their glucose-6-phosphate dehydrogenase. When faba beans are used in animal feeds, there can be effects on performance. These concerns have resulted in increasing interest within plant breeding in developing low vicine and convicine faba bean germplasm. In order to facilitate this objective, we developed a rapid and robust screening method for vicine and convicine, capable of distinguishing between faba beans that are either high (wild type) or low in vicine and convicine. In the absence of reliable commercial reference materials, we report an adaptation of a previously published method where a biochemical assay and spectral data were used to confirm the identity of our analytes, vicine and convicine. This method could be readily adopted in other facilities and open the way to the efficient exploitation of diverse germplasm in regions where faba beans play a significant role in human nutrition. We screened a collection of germplasm of interest to a collaborative plant breeding programme developing between the National Institute for Agricultural Botany in the UK and L'Institut Nationale d'Agronomie de Tunisie in Tunisia. We report the results obtained and discuss the prospects for developing molecular markers for the low vicine and convicine trait.

The phenotypic diversity of 32 landrace populations of tetraploid wheats originating from the Bale and Wello regions of Ethiopia was studied. Eight heritable qualitative traits (glume hairiness, glume colour, awnedness, awn length, beak awn, awn colour, spike density, seed colour) were measured on 2453 individual plants (45–110 plants per landrace). The frequencies of each phenotypic class were used to estimate and analyse the diversity at different levels (population, altitude, region). Beak awn and seed colour showed the highest diversity index, and glume hairiness the lowest. Glume hairiness, glume colour, beak awn and awn colour were regionally variable, while gradients across altitude were observed for glume hairiness, glume colour and beak awn. Variation was, however, largely due to the differences in the level of the different characters within populations. On a regional basis, a higher mean diversity index was observed for materials from Wello than from Bale. No drastic change in the overall diversity between these collections and those analysed in the 1970s was evident.

Cacao (Theobroma cacao L.) was domesticated in Mesoamerica and is native to the South American rainforest. Belizean Criollo is a group of relic landraces that are thought to be similar to those used by the Olmecs and Mayans during early domestication. Knowledge of genetic diversity is essential for efficient conservation and use of these relic landraces. Using 30 microsatellite markers, we characterized genetic diversity in 77 Belize Criollo accessions collected from the Maya Mountains in Belize, and assessed their relationship with 62 cacao accessions including 25 Trinitario accessions. Genetic diversity and heterozygosity were low in Belizean Criollo germplasm. Eleven distinctive genotypes were identified among the Belizean germplasm. Results of ordination and cluster analysis supported their putative ancestral contribution to the Trinitario cacao. However, results of Bayesian assignment and parentage analysis both suggested that the contribution of Criollo cacao to the Imperial College Selections Trinitario is small. Our preferred hypothesis for the genesis of Trinitario cacao is that a limited population of Criollo × Forastero hybrids emanated from the introduced Forastero population of Trinidad. The present study provides new insights into the origin of the Trinitario cacao, which will be useful in the ex situ and in situ conservation of cacao landraces from Mesoamerica.

Cultivars of Miscanthus used as bioenergy crops or tested in trials are largely clonally propagated, wild sourced genotypes or clonally propagated F1 hybrids. One of the most productive taxa is the sterile triploid M. × giganteus. Little domestication or breeding has been undertaken and there is huge potential to utilize the extensive genetic resources of the genus for crop improvement. The challenge is to generate new highly adapted genotypes suitable for a range of environments. Production on marginal land, not used for food crops, is particularly desirable, but presents many barriers to crop breeders, as these are largely unproductive and/or stressful environments. This article outlines progress made in characterizing natural genetic variation in Miscanthus including next-generation single-nucleotide polymorphism genotyping, quantitative trait locus analysis and association mapping. It also explains how this knowledge is being used to develop novel genotypes suited for growth in a broad range of agricultural and marginal lands by defining breeding pools, generating novel crosses, manipulating polyploidy and applying genomic selection approaches.

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.

Ginger (Zingiber officinale Rosc.), originated in the Indo-Malayan region, is now widely distributed across the tropics of Asia, Africa, America and Australia. It was domesticated in India and China, which represent the centre of origin of the species. Cultivated ginger though sterile, exhibits variations in rhizome and vegetative characters. The crop is gaining importance as a curative agent for a variety of ailments. Yield and quality traits (such as essential oil, fibre and oleoresin contents) along with volatile and non-volatile constituents are important determinants of the commodity's end product. Cultivar diversity for yield and morphological features is well known in ginger with few primitive types having excellent quality. However, the common name(s) of ginger cultivars are confusing and have resulted in geographical bias in its ex situ conservation. Most of the molecular/biochemical marker studies reported in ginger show low levels of polymorphism in contrast to plentiful phenotypic variability recorded in the species. The large influence of environmental factors on the content of key compounds, lack of seed set and confusion of the common names are the leading constraints to further varietal improvement of ginger. As tailor-made ginger varieties assume future significance these aspects will have relevance.

The cryopreservation of embryonic axes of two wild and endangered species, Citrusmacroptera Mont. and C. latipes Tanaka, was attempted using air desiccation–freezing, vitrification and encapsulation–dehydration. Successful cryopreservation was achieved in both the species using these three methods. However, the two species responded differently to: the rate of drying and the degree of tolerance to desiccation following air desiccation–freezing; the response to loading duration following vitrification; and to the sucrose concentration during pre-culture following encapsulation–dehydration. C. macroptera was more tolerant to desiccation and freezing than C. latipes with recovery rates of, respectively, 87% and 64%. Recovery from encapsulation–dehydration was 62% for C. macroptera and 45% for C. latipes. In both species, the vitrification protocol gave a significant improvement in recovery rates: 92% and 77% for C. macroptera and C. latipes, respectively. The air desiccation–freezing protocol being a simple and practical technique is recommended for the cryopreservation of these two species.

Microsatellite markers (SSRs) were used to screen and analyse the genetic diversity among clonal genotypes of date palm (Phoenix dactylifera L.) derived by somatic embryogenesis in Oman. Twenty-one palms, representing 14 Omani, five Bahraini, one Iraqi and one Moroccan genotype, were screened with ten microsatellite markers. All primer pairs produced an amplification product in the expected size range and detected high levels of polymorphism among the analysed samples. Correspondence analysis revealed that the genotypes from Bahrain and Iraq showed a close relationship with accessions already grown in Oman. The genotype from Morocco (Medjool) appeared distinct from the rest of the material. Three independent clonal lines derived from a single Khalas Aldahra genotype were found to give identical genetic fingerprints. The value of this work for date palm production and conservation in Oman is discussed.

Anatolia (Asia Minor) is considered to be the cradle of viticulture, but wild grape accessions from this region have not been subjected to any genetic analysis. We present the first genetic characterization of wild grapes (Vitis vinifera subsp. sylvestris) from this region. Using 15 nuclear microsatellites, we genotyped 84 wild grape accessions collected from three Anatolian locations. The unweighted pair group method with arithmetic mean analysis revealed four genetic clusters that partially separated Anatolian wild grape populations. In general, accessions from geographically closer locations showed higher genetic similarities than those from more distant locations. In some cases, accessions from one population showed close genetic relationships to accessions from a different population. The genetic diversity between natural populations from both ends of the Mediterranean basin has shown higher genetic diversity in the Anatolian Peninsula than peripheral populations, suggesting that this area could be one centre of diversity of the species. The genetic relationship between wild and cultivated grapevine from Anatolian Peninsula indicated a clear separation between them. However, we cannot discarded a local genetic contribution. Overall, this study reveals useful information for management and potential utilization of Anatolian wild grape germplasm.

Pennisetum purpureum Schum. (napiergrass) is a perennial grass used for forage especially in South America and Africa. Over the last 30 years, a USDA–ARS nursery containing accessions collected from all over the world has been established in Tifton, Georgia. The study reported here was conducted to assess the molecular genetic variation and genetic relatedness among 89 accessions from the Tifton nursery using amplified fragment length polymorphism markers, morphological data and ploidy level. Using 218 polymorphic markers from eight selective primer combinations, the 89 accessions were clustered into five groups using a principal components analysis and a dendrogram based on Dice similarity estimates and unweighted pair group method with arithmetic average clustering. These five groups include three groups collected from Kenya, a group from Puerto Rico, and accessions derived from the cultivar Merkeron. This research provides the first molecular characterization of the Tifton nursery, displays the relationships between accessions, and provides potential heterotic groups for napiergrass and pearl millet (Pennisetum glaucum (L.) R. Br.) breeding improvement.

Genomic and proteomic diversity provide the basis of evolutionary change by natural selection under abiotic and biotic stresses, and the human-driven evolutionary process of domestication by artificial selection. Described here are some of the regional and local genomic and proteomic long-term multidisciplinary studies conducted at the Institute of Evolution, University of Haifa, Israel, during 1975–2005 (see publications at http://evolution.haifa.ac.il), involving both wild barley, Hordeum spontaneum, the progenitor of cultivated barley and wild emmer sheat, Triticum dicoccoides, the progenitor of modern tetraploid and hexaploid cultivated wheat. Wild cereals harbour large amounts of as yet untapped adaptive genetic resources for crop improvement (resistances against abiotic and biotic stresses, micronutrient metal deficiencies, storage proteins, amylases and photosynthetic yield, among others). The adaptive genomic diversity of wild cereals, including cryptic beneficial alleles at specific quantitative trait loci of T. dicoccoides and H. spontaneum is the best genomic resource to be conserved in situ and ex situ for utilization by classical and modern biotechnologies, to enrich the genetically impoverished and stress-vulnerable food cultivars, advance crop improvement, and thereby increase and optimize world food production in a second genetic green revolution.

Fe and Zn deficiency are widespread worldwide. As wheat is the primary food for the majority of the world people, producing wheat grains with high mineral content can ameliorate the problem of mineral hunger. However, the genetic variation available for breeders is limited. The aim of this study was to assess the genetic variation in grain Fe and Zn contents in 47 synthetic hexaploid wheats and to identify marker loci associated with Fe and Zn contents. We measured the grain Fe and Zn contents using inductively coupled plasma atomic emission spectroscopy and performed genotyping using SSR markers. The results showed considerable genetic variation for these minerals. We identified three lines with high Fe and Zn contents and six quantitative trait loci of which three were associated with Fe content and the other three with Zn content. The minerals showed positive phenotypic and genotypic correlation and high heritability (>60%). The ratio of the σ2g to the σ2g×e was ≥1 for the two mineral contents indicating that breeding for increasing mineral content within the synthetic lines is possible. The synthetic wheat lines identified in this study are valuable genetic resources, and can be utilized for breeding wheat cultivars with high mineral content.