Triticum urartu possesses the Au genome common to bread wheat. Similarly, Triticum monococcum contains the Am genome, which is closely related to the A-genome donor of bread wheat. Aegilops speltoides of the Sitopsis section has the S genome, which is most similar to the B genome of bread and durum wheat when compared with all other wild grasses. Amphiploids developed through bridge crossing between Am/Au and S-genome diploid resources and elite durum cultivars demonstrate enormous diversity to improve both bread and durum wheat cultivars. We evaluated such A-genome amphiploids (Triticum turgidum × T. urartu and T. turgidum × T. monococcum, 2n = 6x = 42; BBAAAmAm/AuAu) and S-genome amphiploids (T. turgidum × Ae. speltoides, 2n = 6x = 42; AABBSS) along with their durum parents (AABB) for their resistance to powdery mildew (PM) at the seedling stage. The results indicated that 104 accessions (53.6%) of A-genome amphiploids (AABBAmAm/AuAu) were resistant to PM at the seedling stage. Of their 24 durum parents, five (20.83%) were resistant to PM and 16 (66.6%) were moderately tolerant. Similarly, ten (50%) accessions of S-genome amphiploids (BBAASS) possessed seedling PM resistance, suggesting a valuable source of major resistance genes. PM screening of the amphiploids and parental durum lines showed that resistance was contributed either by the diploid progenitors or durum parents, or both. We also observed the suppression of resistance in several cases; for example, resistance in durum wheat was suppressed in respective amphiploids. The results from this germplasm screening will facilitate their utilization to genetically control PM and widen the genetic base of wheat.

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.

Solanum aethiopicum L. is indigenous to Africa and constitutes an important vegetable. Morpho-agronomic traits were used to study diversity among 44 accessions of S. aethiopicum groups to identify traits of high discriminatory ability and donor parents with specific or multiple traits for introgression and utilization in breeding programmes. Field experiments were conducted from 2008 to 2010. The principal component (PC) analysis of morpho-agronomic data indicated high discriminatory ability for fruit calyx length, fruit length and leaf length. On PC1, fruit length showed positive and significant correlation coefficients with leaf length, fruit calyx length and width. An independent association was recorded among fruit width, fruits per infructescence and seed yield (t/ha). Ordination (biplot) and grouping (dendrogram) revealed genetic variation and relatedness, phenotypic plasticity and geographical heterogeneity among the accessions within and among the clusters. Members of cluster 1 (group ‘c’) are a promising donor parent for multiple traits (earliness and fruit length), and members of group ‘b’ are superior for fruits per plant, fruits per infructescence and fruit infructescence per plant. Hybridization among distant clusters would provide an opportunity for bringing together gene constellations of diverse background. Earliness and fruit length were highly variable among the S. aethiopicum groups. The results are important for the breeding and selection of this crop.

Investigation of genetic diversity and the relationships among varieties and breeding lines is of great importance to facilitate parental selection in the development of inbred and hybrid rice varieties and in the construction of heterotic groups. The technology of single nucleotide polymorphism (SNP) is being advanced for the assessment of population diversity and genetic structures. We characterized 215 widely cultivated indica rice varieties developed in southern China and at the International Rice Research Institute (IRRI) using IRRI-developed SNP oligonucleotide pooled assay (OPA) to provide grouping information of rice mega-varieties for further heterotic pool study. The results revealed that the Chinese varieties were more divergent than the IRRI varieties. Two major subpopulations were clustered for the varieties using a model-based grouping method. The IRRI varieties were closely grouped and separated clearly from the majority of the Chinese varieties. The Chinese varieties were subclustered into three subgroups, but there was no clear evidence to separate the Chinese varieties into subgroups geographically, indicating a great degree of genetic integration of alleles and shared ancestries among those high-yielding modern varieties.

Eighty-six chickpea (Cicer arietinum L.) genotypes, including 44 Kabuli type and 42 Desi type, were evaluated for their phenological, physicochemical and cooking quality traits. There were significant differences among the genotypes for days to 50% flowering (34–81 d), days to maturity (85–122 d), number of pods per plant (13–66), number of seeds per plant (15–85), 100-seed weight (10.5–58.6 g), seed yield (561–1852 kg/ha), hydration capacity (0.11–0.68 g water/seed), hydration index (0.80–1.21), swelling capacity (0.11–0.7 ml/seed), seed volume (0.1–0.52 ml/seed) and cooking time (38–125 min). The Desi and Kabuli types of chickpea differed significantly from each other for all the traits except for hydration index, swelling index and cooking time. High heritability coupled with high genetic advance was recorded for 100-seed weight, hydration capacity, swelling capacity and seed volume in both Desi and Kabuli genotypes. Seed size (100-seed weight and seed volume) showed significant positive correlations with hydration capacity and swelling capacity. Cooking time did not show any significant positive or negative correlation with any of the traits studied, including seed size, indicating that other additional factors may be involved in controlling cooking time. The results of this study indicate that it is possible to develop cultivars with faster cooking time in both Kabuli and Desi types and in all seed size categories.

The International Crops Research Institute for the semi-Arid Tropics Genebank at Patancheru, India holds the world's largest collection of 22,211 pearl millet germplasm accessions from 50 countries including 4488 landraces from 16 East and Southern African (ESA) countries. Gap analysis using FloraMap software and 3750 georeferenced pearl millet germplasm accessions from ESA countries revealed 34 districts located in 18 provinces of four East African countries and 76 districts located in 34 provinces of seven Southern African countries as geographical gaps. Analysis of characterization data using DIVA-GIS software showed 11 districts of seven provinces in Sudan and Uganda and 58 districts of 20 provinces of seven countries in Southern Africa as gaps in diversity for important morphoagronomic traits. The following districts were identified as gaps common to geographic area and diversity for some or the other traits: Amuria district in Soroti province of Uganda; Mpwapwa in Dodoma province of Tanzania; Mahalapye in Centre province and Kgatleng in Kgatleng province of Botswana; Lalomo in Southern province of Zambia; and Motoko, Mudzi and Wedza in the province of Mashonaland East; Makoni in Manikaland; Gutu and Chivi in Masvingo; Gwanda and Bulalimamangwe in Metabeland south; Hwange and Nkayi in Metabeland north; and Kwe Kwe in Midlands of Zimbabwe. For a successful germplasm collection mission to fill the gaps identified, planning should be made in advance of collaboration and consultation with National Agricultural Systems, local government officials and extension officers. It is suggested to collect the complete passport data including georeference information while collecting the germplasm.

Foxtail millet (Setaria italica (L.) P. Beauv.) is an ideal crop for changing climate and food habits of peoples due to its short duration, high photosynthetic efficiency, nutritional richness and fair resistance to pest and diseases. However, foxtail millet yields are low mainly due to the lack of effort for its improvement and the lack of proper utilization of existing genetic variability. To enhance the use of diverse germplasm in breeding programmes, a core collection in foxtail millet consisting of 155 accessions was established. Core collection accessions were fingerprinted using 84 markers (81 simple sequence repeats (SSRs) and three Expressed Sequence Tag (EST)-SSRs). Our results showed the presence of greater molecular diversity in the foxtail millet core collection. The 84 markers detected a total of 1356 alleles with an average of 16.14 alleles (4–35) per locus. Of these, 368 were rare alleles, 906 common alleles and 82 the most frequent alleles. Sixty-one unique alleles that were specific to a particular accession and useful for germplasm identification were also detected. In this study, the genetic diversity of foxtail millet was fairly correlated well with racial classification, and the race Indica showed a greater genetic distance from the races Maxima and Moharia. The pairwise estimate of dissimilarity was >0.50 except in 123 out of 11,935 pairs which indicated a greater genetic variability. Two hundred and fifty pairs of genetically most diverse accessions were identified. This large molecular variation observed in the core collection could be utilized effectively by breeders or researchers for the selection of diverse parents for breeding cultivars and the development of mapping populations.

Lepidium latifolium L. (Brassicaceae) grows successfully in a high-altitude cold arid environment. Little molecular data are available for this plant despite its immense ecological importance as a cold- and drought-adapted species. We used a novel approach to identify microsatellite regions using genome walker libraries, called as Random Scans at Microsatellite Regions (RaSMiR), and implemented them on genotypes collected from relatively different topographical conditions within a small geographical area. The success rate of finding a microsatellite sequence using this methodology was 100%, and on developing the RaSMiR technique itself as a molecular marker, 230 electrophoretic bands were obtained using 13 different RaSMiR primers in combination with a microsatellite sequence primer. On an average, 17 bands were obtained for each primer. The electrophoretic profiles generated by RaSMiR markers were distinct from those produced by inter-simple sequence repeat markers. This information has been documented as a dominant marker data, and has been used to construct a neighbour-joining tree that successfully distinguished all genotypes. RaSMiR is an attractive approach for the development of unique and informative microsatellites, or for genome scanning directly as a molecular marker that can potentially be employed for the estimation of genetic diversity or to identify polymorphic loci involved in adaptations particularly in the non-model species, for which sufficient genomic data are not available.

Theobroma cacao L., or cacao, is the source of cocoa products used in the making of chocolate. These tropical trees are conserved in living genebanks. The International Cocoa Genebank, Trinidad is one of the largest ex situ collections in the public domain. Mislabelling is a critical problem and the correction of this problem is vital to improve the accuracy and efficiency of genebank management. Using microsatellite DNA markers, we assessed the level of mislabelling in a group of Refractario cacao that originated from Ecuador and determined their population memberships through Bayesian clustering analysis. The microsatellite data revealed a synonymous rate of 7.5% and an error rate of 39.4% in this germplasm subset. The analysis of the population structure grouped the Refractario accessions into four subclusters, indicating intra-population heterogeneity in this germplasm group. Based on the results, we recommend that when the assignment test is used for cacao genotype identification, it should (a) use duplicated samples as internal checks, (b) choose suitable reference accessions, including a known homogeneous group and (c) employ subclustering checks to obtain reliable results. The information framework generated is discussed in relation to the management of the collection, population enhancement and future research of the collection.

To facilitate the updating of in situ and ex situ conservation strategies for wild taxa of the genus Hordeum L., a combined ecogeographic survey and gap analysis was undertaken. The analysis was based on the Global Inventory of Barley Plant Genetic Resources held by ICARDA plus additional datasets, resulting in a database containing 17,131 wild Hordeum accessions. The analysis concluded that a genetic reserve should be established in the Mendoza Province of Argentina, as this is the most species-rich area globally for Hordeum. A network of reserves should also be set up across the Fertile Crescent in Israel, Palestine, Syria, Jordan, Lebanon and Turkey to provide effective conservation within the centres of diversity for gene pools 1B (Hordeum vulgare subsp. spontaneum (C. Koch) Thell.) and 2 (Hordeum bulbosum L.). The majority of the species were deemed under-collected, so further collecting missions are required worldwide where possible. Although ex situ and in situ conservation strategies have been developed, there needs to be further investigation into the ecological environments that Hordeum species occupy to ensure that any adaptive traits expressed are fully conserved. Additionally, studies are required to characterize existing collections and test the viability of rare species accessions held in genebanks to determine whether further ex situ collections are required alongside the proposed in situ conservation.

A total of 60 farmers' cacao accessions (Theobroma cacao L.) from Nicaragua were investigated using microsatellite markers to reveal their genetic composition and to identify potentially resistant genotypes against the black pod disease caused by Phytophthora palmivora. These accessions were compared with 21 breeders' accessions maintained locally, two Criollo accessions from Costa Rica and two accessions from Ecuador. The analyses showed a low level of differentiation among groups of farmers' accessions (FST = 0.06) and that six Nicaraguan accessions were genetically closely related to the two Criollo accessions used as a reference. In addition, seven distinct genotypes were found to have allelic composition that may indicate linkage to resistance alleles, thus being potential parental lines in future breeding programmes.

Fusarium wilt caused by Fusarium oxysporum, Schlecht. emend. Snyd. & Hans. f. sp. ciceri is prevalent in most chickpea-growing countries and is a major devastating disease. Host plant resistance is the most practical method of disease management. Indigenous chickpea germplasm reveals a heterogeneous genetic make-up and the response of resistance to wilt is an unexplored potential source for disease resistance. There are 70 indigenous germplasm lines selected on the basis of their agronomic performance and diverse areas of collections in the country. Of these, four accessions had a highly resistant score of 1 and six had a score of 3 using a 1–9 rating scale, indicating their level of resistance to Fusarium wilt (race 4). Other germplasm accessions of chickpea were found to be moderately resistant to highly susceptible disease reaction. Likewise, the same set of germplasm was also screened for Meloidogyne incognita (race 1) using pot culture under controlled condition. Only one accession was found to be resistant to this pest. These resistant gene sources can be utilised effectively for race-specific chickpea wilt and root-knot resistance breeding programmes.