Terminal-repeat retrotransposon in miniature (TRIM) elements are a miniature form of retrotransposons and play an important role in genome organization. The Cassandra TRIM family has been identified in over 50 plant species, including both monocots and dicots. Cassandra elements carry an independently transcribed 5S RNA sequence in their terminal repeat regions, which is unique compared with other TRIM families. Although the existence of Cassandra elements has been documented in many plants, much work remains to characterize Cassandra family members and elucidate their distribution. In this study, we comparatively analysed the Cassandra family members in the Brassica oleracea, B. rapa and Arabidopsis thaliana genomes. A total of 602, 451 and 173 members, of which 130, 60 and 9 were relatively intact, were identified from the B. oleracea, B. rapa and A. thaliana genomes, respectively. Most of the Cassandra elements (1120/1226) were found in intergenic spaces, but 106 elements were inserted in genic regions such as introns, exons and untranslated regions. Our comparative analysis of the Cassandra family members in A. thaliana, B. rapa and B. oleracea reveals that some Cassandra elements have been commonly retained during the last 20 million years in three species and some elements have been uniquely evolved in Brassica species. This study promotes our understanding of the role and utility of Cassandra elements in the evolution of the Brassicaceae family.

In this study, 15 morphological traits and 16 microsatellite markers were used to assess the morphological variability and structure of 68 (33 local and 35 foreign) almond accessions (Prunus dulcis (Mill.) D.A. Webb). Extensive phenotypic diversity was found among the accessions, and results indicated a high variation in leaf and fruit traits. Varieties were separated into two distinct groups with a similarity coefficient of 0.761. Morphological traits were categorized by principal component analysis into five components, which explained 86.5% of the total variation. Nut and kernel traits were dominant in the two first components, accounting for 49.4% of the variation. By contrast, leaf traits accounted for 18.4% of the variation in the third component. The results of molecular analysis (Bayesian clustering approach) did not correspond to morphological groupings, and the second approach was more discriminate. The combination of both approaches revealed the richness among the collected plant materials, which will be useful in breeding programmes of this species.

Zingiber barbatum Wall. (family Zingiberaceae), is an underutilized medicinal plant and commonly known as ‘Meik tha-lin’ in Myanmar where it is used in the indigenous system of medicine. In the present study, 19 accessions of Z. barbatum from five provinces in Myanmar have been utilized to characterize and assess genetic diversity. Twenty-nine morphological characters were noted, including growth habit, leaf, pseudo-stem and rhizome characters. Fifteen primer sets of P450-based analogue (PBA) markers were used to reveal molecular characteristics. Of the 29 morphological characters, 22 showed a high degree of variation within wild ginger accessions, whereas 20 of these characters contributed significantly to morphological variation. Eleven amplified primer sets gave a total of 175 bands and exhibited 92.15% polymorphism across Z. barbatum accessions. Based on morphological characters and PBA markers, 19 accessions can be divided into two morphotype groups with comparatively higher genetic diversity. This information can be applied in future crop improvement, proper conservation and better use of this underutilized medicinal species.

Global food security could be imperilled by the combined pressures from the effects of continually evolving climatic conditions, demographics and other socio-economic factors, the demands of the livestock, bioenergy and fibre industries for food-based substrates, the static or decreasing availability of natural resources for agriculture and the impracticality of increased use of economically and environmentally costly agricultural inputs. The optimal harnessing of plant genetic resources for food and agriculture (PGRFA) in manners that translate their repertoire of hidden potentials into significantly enhanced crop productivities has been severally identified as crucial to achieving the required considerably significant increases in food production. The scope of the problems and the plausible means for addressing them compel the devising of novel and more efficient ways for deploying PGRFA in need-based crop improvement programmes. We posit a continuum approach to the management of PGRFA which links seamlessly the effective conservation and access to PGRFA through their use in developing superior and resilient crop varieties to the provision of their high-quality seeds and planting materials to the growers. To achieve the mainstreaming of this paradigm, we propose the institutionalization of overarching national PGRFA strategies that prescribe result-oriented action plans spanning above three components of the management of PGRFA for a country's priority crops. We also describe the strategy as a means for identifying and assigning responsibilities to critical stakeholders and providing for the governance of all aspects of PGRFA activities over specific time frames. Steps to developing and adopting a national PGRFA strategy are also suggested.

A diverse set of 107 rice genotypes was evaluated for yield, shattering and dormancy traits. Analysis of variance revealed sizable variation while skewness and kurtosis values indicated near-normal distribution for most of the traits, thus quantitative nature controlled by many genes. A highly significant deviation from a normal distribution for dormancy and shattering % indicated their qualitative nature of inheritance. Four promising genotypes ‘IRGC1723’ (early with 65 days to flowering), ‘IRGC 11108’ and ‘RNR 15459’ (high grain number – 358 and low average shattering – <5%), ‘RNR 11718’ (high single plant yield – 56.73 g, low average shattering – <5% and dormancy period – 21 days) are identified. A significant positive correlation between shattering and dormancy confirms inter-relationship among domestication-related characteristics. The principal component analysis revealed the contribution of four PCs to maximum variability and hierarchical clustering grouped the genotypes into 18 divergent clusters. Five cultivars (Karimnagar Samba, Sheetal, PR 121, Pranahitha and Jagitial Samba) with a combination of low shattering ability (3.35–5.7%) and considerable dormancy period (13–20 days) falling in the same cluster can be used as donors for the improvement of rice genotypes with low shattering ability and incorporating a considerable period of dormancy so as to avoid pre-harvest sprouting due to delayed harvesting. Further, they can be crossed with ‘Pratyumna’ having less than 1 week dormancy period, a genotype of the cluster XVII with which they have a maximum genetic divergence of 51.4 and may serve as parents in the development of mapping populations for the identification of QTLs/genes for shattering and dormancy traits.

The 17 Brazilian species of Adesmia DC were analysed, using 20 primers, with regard to their randomly amplified polymorphic DNA (RAPD) patterns. From a total of 357 individuals analysed, the 20 primers produced 2249 fragments with molecular sizes ranging from 200 to 2700 bp, 56% of which were polymorphic. Average intra-population genetic similarity, estimated by Jaccard's coefficient, ranged from 0.35 in A. araujoi to 0.80 in A. punctata. Mean intra-specific genetic similarity varied greatly among species, ranging from 0.19 for A. tristis to 0.89 for A. arillata. Mean genetic similarity among the species, estimated by Dice's coefficient, was 0.56. RAPD markers were efficient at separating all the accessions analysed. The results obtained generally agreed with the partition of genetic variability expected according to the mode of reproduction.

Tomato (Solanum lycopersicum) fruit quality and yield are highly dependent on adequate uptake of nutrients. Potassium, magnesium and calcium are essential elements that influence fruit quality traits such as colour, uniformity of ripening, hollow fruit, fruit shape, firmness and acidity. Sodium is not an essential element for tomato and can detrimentally compete with the absorption of potassium and calcium. Daily intakes of potassium, magnesium and calcium in human diets are typically below healthful levels, while sodium intake is often excessive. The objective of this study was to compare 52 diverse commercially important varieties of tomato for concentrations of potassium, magnesium, calcium and sodium in fruits. The tomatoes were produced in replicated plots in Geneva, NY in 2010 and 2011. Multiple fruits per plot were harvested vine-ripe, homogenized and assayed for cations. Analysis of variance showed significant differences among the 52 varieties for all four traits, i.e. cation concentrations (df = 51, P < 0.0001–0.0034) and no significant differences between years for any trait (df = 1, P = 0.3432–0.6770). Factor analysis showed a strong interrelationship between potassium and magnesium that was independent of calcium and sodium. Potassium and magnesium were highly significantly correlated with each other (r = 0.64, P < 0.0001). No other correlations between pairs of traits were observed. Results supported a genetic basis for potassium, magnesium, calcium and sodium concentrations that was consistent across environments (i.e. years). Results can contribute to the development of cultivars with favourable cation profiles in terms of human health and fruit quality.

Chickpea (Cicer arietinum L.) is an important food legume crop grown mostly in Asia and Africa as well as in other parts of the world, and serves as an important source of protein in the diets of vegetarian people. Lot of variation in grain quality traits has been observed in cultivated chickpea in both desi and Kabuli types. It has often been observed that seeds with smaller size have more protein when compared with those with larger size. The joint dependence of these two traits on the same primary characteristics results in this negative relationship. This negative correlation coupled with breeding efforts aimed at increasing grain yield has hampered the progress of improving these two traits simultaneously. Therefore, a germplasm exhibiting wider variability for these quantitative traits is an important resource for the identification of novel alleles. Herein, we report the wide variation observed for five important quantitative traits including days to flowering, days to maturity, plant height, 100-seed weight and protein content, and also report the significant positive correlation observed between 100-seed weight and protein content in a diverse collection of chickpea germplasm comprising both desi and Kabuli types.

Microbe-associated molecular pattern (MAMP)-triggered immunity (MTI) is an important component of the plant innate immunity response to invading pathogens. Although several MTI responses can be measured in different plant species, their magnitude is probably plant species specific and even cultivar specific. In this study, a genome-wide transcriptome analysis of two soybean parental lines and two progeny lines treated for 30 min with the MAMPs flg22 and chitin was carried out. This analysis revealed a clear variation in gene expression, under both untreated and flg22+chitin-treated conditions. In addition, genes with potential additive and non-additive effects were identified in the two progeny lines, with several of these genes having a potential function in the control of innate immunity. The data presented herein represent the basis for further functional analysis that can lead to a better understanding of the soybean innate immunity response.

The technique of excised embryos was employed to facilitate the propagation of Podophyllum emodi derived from seeds collected at the different elevation zones of Himachal Pradesh, India. Seed germination was low, irrespective of stage of seed development or zone of collection. Germination was improved significantly (89.14%) in the partially mature and mature seeds collected from alpine and temperate zones when excised embryos were cultured on basal B5 medium. Leaf emergence and plant establishment in the field was also significantly higher in the plants raised through this technique, despite hypocotyl dormancy. The technique was successfully employed for the production of plants to be reintroduced in large numbers into their habitat in the Great Himalayan National Park.

Genetic relationships among elite celeriac varieties and celeriac accessions conserved in genebanks are generally unknown. The objective of this study was to use amplified fragment length polymorphism (AFLP) markers and morphological characterization to identify material that could be of use in celeriac breeding. Genetic relationships were estimated in 34 elite celeriac varieties bred in Europe and 28 celeriac accessions conserved at the German genebank. Two varieties of celery, two varieties of leaf celery and three genebank accessions of wild Apium species were additionally analysed. Fifteen EcoRI/MseI-based AFLP primer combinations were used. Polymorphic AFLP fragments were scored for calculation of Jaccard's coefficient of genetic similarity (GS). Morphological distances (MD) were determined based on 11 morphological traits. Average GS estimate in elite germplasm (GS=0.90) was higher than in exotic germplasm (GS=0.80). An AMOVA (analysis of molecular variance) revealed that a high proportion of variation was due to variation within elite celeriac varieties and genebank accessions. Although GS and MD matrices were poorly correlated (r=0.22), UPGMA (unweighted pair group method using arithmetic averages) cluster analyses revealed clear genetic groupings of celeriac germplasm, which was supported by morphological traits. Elite, moderately bred and exotic varieties formed distinct clusters, indicating that only a part of the available genetic diversity in celeriac germplasm has been exploited in breeding. Distinct Apium species might be useful for the introgression of new genes into cultivated celeriac material. Broadening of celeriac collections in genebanks and detection of new genetic resources are vital for improvements in celeriac breeding.

Faba bean (Vicia faba L.) was used as the rootstock for lentil scions to test the feasibility of using in vivo inter-generic grafting techniques as a substitute for root induction and as a tool in lentil genetic improvement. An accession of each of the six wild Lens species was used as the scion in grafts to faba bean breeding line FB50-9 rootstock. Successful grafts were obtained for all species with survival of grafts to seed maturity between 70.7 and 87.7% except for Lens orientalis PI 72735 with 55.3% survival. Days to flower remained the same after grafting, except for scions of L. nigricans PI 72560 and L. orientalis PI 72735 which had a lag phase of 9 and 7 d, respectively. For all six wild species, seed diameter and seed weight were not significantly different between non-grafted controls and scions grafted onto faba bean rootstocks. This simple approach opens the possibility of using in vivo grafting techniques to rescue inter-specific hybrids of lentil. The technique has potential as a useful tool in lentil breeding, as a means of improving seed multiplication rate of rare genetic resources of wild lentil and as a way to reduce the costs of germplasm multiplication of wild lentil species.

The Germplasm Enhancement of Maize (GEM) Project is a cooperative effort between the USDA-ARS, private industry and public researchers to broaden and enhance the germplasm base of maize. In this program, selected accessions from the Latin American Maize Project, and seven tropical hybrids donated by DeKalb to the GEM Project, were crossed to elite proprietary inbred lines contributed by commercial plant breeding programs. In most cases, the resulting hybrids were crossed to a second commercial inbred line and the resulting 25% exotic hybrids were used as breeding populations for further development. To identify GEM germplasm with value to protein quality breeding programs, we developed a process for evaluating the content of the essential amino acids methionine, lysine and tryptophan in the grain of GEM germplasm that balances the need for multiple-year evaluations with the constantly changing entry list of this germplasm screening program. This process involves annual field trials with common checks. Weak entries are dropped from the trial each year to make room for new entries, while strong entries are retained. Methionine exhibited the most significant variation, followed by lysine and then tryptophan. A number of GEM lines had methionine or lysine levels that were significantly better than Corn Belt checks and some were competitive with high-amino acid checks.

Yams (Dioscorea spp.) are one of the main root and tuber crops in the world, especially within the species complex Dioscorea cayenensis/D. rotundata. Few studies have been conducted in Brazil with these species, including genetic diversity. The objective of this study was to characterize the genetic diversity of local varieties of D. cayenensis and D. rotundata using morphological and molecular markers, and provide information on the management and use of the crop by family farmers from different regions in Brazil. Thus, yam tubers were sampled from several municipalities in the South, Southeast and Northeast regions. Eighteen morphological traits and ten microsatellite loci were used to analyse 47 yam accessions (23 D. cayenensis and 24 D. rotundata). Species identification was carried out after field morphological evaluation. Spatial genetic analysis indicated significant structure among the local varieties, mostly between regions and species. Both cluster and Bayesian analyses showed a separation of the accessions into two distinct groups: group I with accessions originated from the Southeast region and group II with accessions originated from the Northeast region, while accessions from the South region were intermediate or included in either group. The results showed a separation between D. cayenensis and D. rotundata accessions in Brazil, and that D. cayenensis occurs predominantly in the Southeast region, while D. rotundata occurs in the Northeast region. Further studies with larger sampling would be welcome in order to confirm these findings. Also, this study highlights the importance of family farmers in the genetic diversity conservation of these species in Brazil.

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.

The Triticeae tribe (Poaceae) includes several important cereal crops, cultivated forages, annual and perennial grass weeds and ecologically diverse native North American grasses. Elymus L. is the largest and most complex genus in the Triticeae tribe with approximately 150 polyploid perennial grass species occurring worldwide. The genomic constitutions of approximately 40% of the Elymus species are unknown. Molecular markers are needed to facilitate genetic analysis of diversity and functional traits in these species. We have developed simple sequence repeat (SSR) markers for use in Elymus based on Elymus expressed sequence tag sequences. To test the polymorphic content and transferability of these SSRs, 100 SSR primer pairs were tested on 84 plants representing seven North American Elymus, Pseudoroegneria and Pascopyrum species. The number of bands produced from each of the SSRs ranged from 1 to 11 with an average of 4.3 bands/SSR. A subset of the 23 most polymorphic SSRs produced 142 bands, an average of 6.2 bands/SSR. Binary data from the 100 SSRs successfully separated all individuals into their respective accessions in a neighbour-joining phylogram with a 100% confidence interval. Analysis of molecular variance showed that 29.9% of the total variation was within and 70.1% was among the accessions. These SSRs will be a useful tool for investigating genetic diversity, genome constitutions and molecular mapping in Elymus and other Triticeae grasses.

The diversity within 20 rice varieties used as progenitors in Cuban rice breeding programmes was analysed with respect to agro-morphological traits, pedigree and DNA markers. Eleven agro-morphological traits were scored, and phenotypic (Euclidian) distances between the rice varieties were calculated. Sixty random amplified polymorphism DNA (RAPD) and 115 amplified fragment length polymorphism (AFLP) bands served to determine Dice's distance estimates. Cluster analyses were performed based on genetic distance matrices using the unweighted pair-group method of arithmetical means (UPGMA) as the clustering method. This analysis showed five phenotypic, six genealogical, five RAPD and six AFLP diversity groups. Genetic diversity estimates based on RAPD data, but not on AFLP, efficiently represented the genetic parentage and phenotypic diversity between rice varieties. Combined diversity estimates allowed the identification of 11 different genetic pools and permitted a more effective separation of the progenitor set than those obtained solely by phenotypic and genealogical information. The results of this study stress the necessity to diversify rice parental stocks for further breeding purposes.

Climate change-induced events are causing salinization of many rice-growing areas, requiring the identification of new sources of genetic variation for salt tolerance in plant genetic resources since commonly grown cultivars are sensitive to salt. To identify the level of salt tolerance across a wide range of genotypes, we used a multivariate screening method using multiple growth and physiological traits simultaneously. For this purpose, four indica, two japonica and two wild rice genotypes were grown hydroponically under 40 and 80 mM NaCl stresses; fourteen different growth, qualitative and physiological traits, e.g. plant height, biomass, root and shoot elongation rates, and tissue ion accumulation, were recorded. In general, indica varieties performed better than both japonica and wild species. Our approach identified the existence of qualitatively different mechanisms of salt tolerance across the genotypes. For example, Pokkali, a salt-tolerant indica variety, displayed both ‘Na exclusion’ and ‘ion balance’ mechanisms, whereas PSBRc50 and IR58 showed only ‘Na exclusion’, and the Japonica genotypes Banikat and Nipponbare showed only ‘ion balance’. The results demonstrated that the tolerance is dependent on the level of stress and that this varies between genotypes; Nipponbare is moderately tolerant to 40 mM NaCl but not to 80 mM. We also suggest that the use of multivariate analyses can simplify the complex salinity tolerance picture and can effectively reveal the salinity tolerant genotype from a wide range of germplasm. The results reported here identify different physiological mechanism of tolerance across the genotypes and provide a sound basis for future studies examining their underlying molecular mechanisms.

Sinapis alba L. is a major specialty crop grown as a condiment in western Canada, but little is known about its genetic diversity. The objective of this study was to assess the level and pattern of genetic diversity in a collection of 127 S. alba accessions held at Plant Gene Resources of Canada using amplified fragment length polymorphism (AFLP) markers. Five AFLP primer pairs were applied, and 134 polymorphic bands were scored for each accession. These scored bands had frequencies of occurrence ranging from 0.02 to 0.99 with an average of 0.69. More AFLP variation was found within single (79.1%) than between (20.9%) S. alba accessions. A small degree of AFLP difference (1.7%) was observed among the accessions of various regions, while relatively large variation (9.2%) existed among the accessions of various countries. A large AFLP difference (15.6%) also existed between the yellow- and brown-seeded accessions, but only 6.2% difference was observed between the cultivar and landrace accessions. Two distinct groups of S. alba germplasm were identified on the basis of the seed colour (yellow or brown), although a few mixtures also existed. No apparent ‘duplicated’ accessions were observed. The most diverse accessions were from Italy, Spain, France and Greece. Among the most genetically distinct accessions were SA97 from Portugal, SA89 and SA88 from France, SA83 from Russia and SA57 from Italy. These findings are significant not only for managing S. alba germplasm, but also for identifying diverse germplasm that can be used by plant breeders to improve S. alba seed yield and quality parameters.

Drought stress negatively affects the cotton production all over the world. The negative impact of drought varies for different species due to some morphological and root attributes that help some species to better stand under drought. But the extent of disturbance varies for different cotton species. To find out such variation, two cotton species (Gossypium hirsutum and Gossypium arboreum) were studied under normal and drought conditions for 2 years. Two genotypes for each species were included, i.e. PC-1 and COMILLA (G. arboreum) and IUB-13 and IUB-65 (G. hirsutum). The experiment was laid out under a completely randomized design following factorial arrangement. Genotype × treatment × year interaction of cotton genotypes was studied for different root, morphological, physiological and fibre-related traits. Traits such as above ground dry biomass, above ground fresh biomass, chlorophyll contents, leaf area, seed cotton yield, sympodial branches/plant, fibre strength and ginning out-turn were higher in G. hirsutum genotypes as compared to G. arboreum genotypes. However less reduction under drought in all above mentioned traits was recorded for G. arboreum, than G. hirsutum. Furthermore, root traits; primary root length, lateral root numbers, root fresh weight and root dry weight were enriched under drought condition in G. arboreum genotypes than in G. hirsutum genotypes, which is a clear manifestation of higher drought tolerance ability in G. arboreum genotypes transferrable to G. hirsutum genotypes through interspecific crossing or other means.