Astronium concinnum Schott ex Spreng. (Anacardiaceae) is a species used in civil construction, naval, luxury furniture, in addition to the potential for recovery and restoration of habitats. The objective of this work was to characterize the diversity and genetic structure of the A. concinnum in the Conservation Units, National Forest of Pacotuba and Private Natural Heritage Reserve of Cafundó, located in the south of the state of Espírito Santo. Eight ISSR primers were used, which produced 121 DNA fragments and 73.55% polymorphism. In the analysis of genetic dissimilarity, seven distinct groups were identified, with the majority of individuals (from both Conservation Units) being brought together into a single group. The genetic diversity of Nei (H*) and the Shannon index (I*), provided values for the species of 0.312 and 0.473, respectively, indicating the genetic diversity conserved in the species and its potential use for collecting genetically diversified seeds. The analysis of molecular variance revealed that most of the diversity (92.54%) is distributed within populations and the value of gene flow (Nm = 10.629) indicates the high rate of genetic exchange between Conservation Units. The results of the genetic structuring indicated the division of individuals into three genetic groups (K = 3), however, it was possible to observe a mixture of genetic material with the sharing of alleles between the three groups. The results indicate that A. concinnum trees maintain genetic diversity for their maintenance. In addition, the potential of the analysed individuals was certified as future matrixes for seed collection.

Applied genetics combined with practical plant breeding is a powerful tool in agricultural development and for food security. The Green Revolution spurred the world's potential to meet its food, feed and fibre needs at a time when vast regions were notoriously food-insecure. Subsequent adaptations of such strategies, from the late 1980s onwards, in order to develop new plant varieties in a more participatory way, have strengthened the focus on applying technology to farmers' diverse needs, feeding research results into a variety of seed systems. During these developments, there were no major legal impediments to the acquisition of either local or formal knowledge or of the building blocks of plant breeding: genetic resources. The emergence of molecular biology in plant science is creating a wealth of opportunities, both to understand better the limitations of crop production and to use a much wider array of genetic diversity in crop improvement. This ‘Gene Revolution’ needs to incorporate the lessons from the Green Revolution in order to reach its target groups. However, the policy environment has changed. Access to technologies is complicated by the spread of private rights (intellectual property rights), and access to genetic resources by new national access laws. Policies on access to genetic resources have changed from the concept of the ‘Heritage of Mankind’ for use for the benefit of all mankind to ‘National Sovereignty’, based on the Convention on Biological Diversity, for negotiated benefit-sharing between a provider and a user. The Generation Challenge Programme intends to use genomic techniques to identify and use characteristics that are of value to the resource-poor, and is looking for ways to promote freedom-to-operate for plant breeding technologies and materials. Biodiversity provides the basis for the effective use of these genomic techniques. National access regulations usually apply to all biodiversity indiscriminately and may cause obstacles or delays in the use of genetic resources in agriculture. Different policies are being developed in different regions. Some emphasize benefit-sharing, and limit access in order to implement this (the ‘African Model Law’), while others, in recognition of countries' interdependence, provide for facilitated access to all genetic resources under the jurisdiction of countries in the region (the Nordic Region). There are good reasons why the use of agricultural biodiversity needs to be regulated differently from industrial uses of biodiversity. The International Treaty on Plant Genetic Resources for Food and Agriculture, which entered into force in 2004, provides for facilitated access to agricultural genetic resources, at least for the crops that are included in the Treaty's ‘Multilateral System of Access and Benefit-sharing’. Ratification of the Treaty is proceeding apace, and negotiations have entered a critical stage in the development of practical instruments for its implementation. Although the scope of the Treaty is all plant genetic resources for food and agriculture, there are important crops that are not covered by its Multilateral System. Humanitarian licences are being used to provide access for the poor to protected technologies: countries may need to create such a general humanitarian access regime, to ensure the poor have the access they need to agricultural genetic resources.

Increased amino acid content in high-oil maize (Zea mays L.) grain may add further value to its use in livestock rations, especially if this enhanced amino acid content is consistent across varying growing conditions. Most high-oil maize (HOM) grown in the USA utilizes the TopCross system which involves planting a blend (TC Blend) of two types of maize. Field experiments and on-farm studies were conducted in 1997 and 1998 to compare the amino acid profile of grain from HOM TC Blends with that of their normal-oil maize (NOM) counterparts across a range of production environments in Ohio. In 1997, the composition of four amino acids (lysine, methionine, glycine and arginine) was significantly higher in HOM compared to NOM grain. In 1998, nine amino acids (lysine, methionine, glycine, arginine, asparagine, threonine, serine, cysteine and tryptophan) were greater in HOM than in NOM grain. Lysine and methionine content in HOM grain averaged 12 and 13% higher than in NOM grain in both years. The number of amino acids significantly affected by the grain parent was greater than that for maize type each year. A significant maize type × grain parent interaction for a limited number of amino acids suggest that TC Blend grain parents may affect the consistency of amino acid composition in HOM grain. Results of this study demonstrate that the levels of several amino acids, including economically important lysine and methionine, were consistently greater in HOM than in NOM grain across a range of production environments. Modelling with livestock ration balancing software showed that the additional amino acids and oil in HOM added 12–20% to its value as livestock feed.

Wild relative of okra, Abelmoschus angulosus Wall. ex Wight & Arn. was identified as a resistant germplasm for Okra Yellow Vein Mosaic Virus (OYVMV) which is the devastating disease for okra cultivation in Sri Lanka. The mode of resistance of OYVMV in A. angulosus was studied with the aim of tagging responsible genes for the disease resistance. Wide hybridization was performed between A. angulosus and highly virus susceptible A. esculentus variety, MI-7. Very poor seed setting was observed in F1 and F2 generations due to post zygotic abortion. Disease screening was carried out using F1 and F2:3 populations along with parents in the field under induced disease pressure. Disease severity index and area under disease progress curve were calculated to measure disease severity. Number of genes segregating for OYVMV disease resistance was calculated for the F2:3 generation. Modified Wright's formula was used to estimate the effective gene number and mode of inheritance by a quantitative method. A χ2 test was performed for qualitative analysis. Plants of A. angulosus were totally free of virus incidence while 100% disease incidence was observed in the variety MI-7. F2:3 population showed between and within progeny segregation for disease incidence. Results indicated that the disease susceptibility was dominant over resistance. χ2 analysis revealed that the segregation of disease severity was significantly fit to the gene model of 9:6:1 (χ2 = 0.1757 at P ≤ 0.05) suggesting the disease resistance in A. angulosus is governing by two recessive genes in an additive manner. Result was confirmed by the quantitative analysis.

VQ-domain proteins are known to interact with WRKY transcription factors and have been reported to be involved in plant defence responses to environmental stresses in Arabidopsis. Thus, elucidation of the defence mechanisms during the interaction of VQ-domain proteins and WRKY transcription factors could provide useful insights into the regulation of VQ-domain protein-mediated WRKY transcription factors. As the focus of this review, we summarize the genomic analysis of the VQ-domain proteins as one of the WRKY-interacting proteins and their biological effects during plant stress conditions in Arabidopsis and rice.

Southern Sudan has a rich tree flora. Trees are important in the livelihoods of the numerous tribes of the region, who use them for shelter, fuel, food, fodder, medicine and income generation. The gallery and depression forests contain valuable timber trees. Other species provide non-timber forest products that are potentially tradable outside Sudan, particularly in African countries that have over-exploited their own forest resources. As the carrying capacity of the western and central areas of Sudan decreases, the pressure on the natural resources of the higher rainfall southern areas will increase. This in itself might initiate conflict, as various tribes compete over a relatively rich resource base. The recent peace established between the north and south could result in depletion of the forest resources of the south through commercial exploitation. This paper details and discusses the wild tree resources of southern Sudan, including many already threatened species.

Season-long monitoring of on-farm rice (Oryza sativa, L.) plots in Nepal explored farmers' decision-making process on the deployment of varieties to agroecosystems, application of production inputs to varieties, agronomic practices and relationship between economic return and area planted per variety. Farmers deploy varieties [landraces (LRs) and modern varieties (MVs)] to agroecosystems based on their understanding of characteristics of varieties and agroecosystems, and the interaction between them. In marginal growing conditions, LRs can compete with MVs. Within an agroecosystem, economic return and area planted to varieties have positive relationship, but this is not so between agroecosystems. LRs are very diverse on agronomic and economic traits; therefore, they cannot be rejected a priori as inferior materials without proper evaluation. LRs have to be evaluated for useful traits and utilized in breeding programmes to generate farmer-preferred materials for marginal environments and for their conservation on-farm.

In this study, a forward-genetics analysis was performed on a portion of TILLMore, a chemically mutagenized population of barley cv. ‘Morex’ (http://www.distagenomics.unibo.it/TILLMore/), to identify root morphology alterations by comparison with ‘Morex’ wild-type. For this purpose, a simple paper-roll approach was performed to identify phenotypic variants at the seedling stage. The analysis of c. 1000 M4 families allowed us to identify c. 70 lines with altered root morphology. A more accurate phenotypic characterization of a portion of the mutant lines has been performed using stereomicroscopy and a scanning electron microscopy approach.

Crop wild relatives are an increasingly important source of plant genetic resources for plant breeders. Several studies have estimated the effects of climate change on the distribution of crop wild relatives, using species distribution models. In this approach, two important aspects, i.e. species' dispersal capacity and founder effects, are currently not taken into account. Neglecting these aspects can lead to an underestimation of the climate change-induced threat to the size of the species range and the conservation of range-wide levels of genetic diversity. This paper presents two recommendations for the interpretation of the results obtained with these models. The integration of process-based simulation models and statistical species distribution models will facilitate the inclusion of dispersal processes and founder effects in future assessments of the resilience of plant genetic resources under climate change.

Yellow endosperm maize can be used to reduce vitamin A deficiency among many pre-school children and women of reproductive age in sub-Saharan Africa. Assessment of the genetic diversity of tropical yellow endosperm maize inbred lines will have genetic gains in breeding design to develop lines with an enhanced level of provitamin A. We screened 122 tropical yellow endosperm maize inbred lines with 62 simple sequence repeat (SSR) markers and 51 SSR loci were polymorphic. We detected 190 alleles with an average of 3.72 alleles per locus, and polymorphic information content values among the inbred lines varied from 0.12 to 0.74 with an average of 0.43. Genetic distance (GD) values among all the pairs of the 122 inbred lines varied from 0.02 to 0.61 with an average of 0.41 for the SSR markers. The inbred lines exhibited a substantial level of genetic diversity. Genetic diversity was also evaluated using carotenoid data. The Euclidean GDs varied from 1.00 to 9.97 with an average of 3.81 for the carotenoid data. Cluster and principal coordinate analyses revealed clear separation of maize inbred lines into SSR-based groupings and carotenoid-based groupings. Cluster based on SSR markers were predominantly consistent with known pedigree data of the inbred lines. The correlation using Mantel's test between carotenoid-based GD estimates and SSR marker-based GD estimates gave a low r value ( − 0.06). The grouping of lines will facilitate the selection of parental lines for making crosses to develop new lines with enhanced provitamin A content.

We have established mutant collections of the model species Medicago truncatula according to current protocols. In particular, we used a transposon (Tnt1) tagging method and an ethyl methanesulfonate (EMS) mutagenesis approach (TILLING). The collections were subjected to both forward and reverse genetics screenings, and several mutants were isolated that affect plant traits (e.g. shoot, root developments, flower morphology, etc.) and also biosynthetic pathways of secondary compounds (saponins and tannins). Genes responsible for some of the mutations were cloned and further characterized.

Pigeonpea is an important grain legume. It contributes to the improvement of soil fertility through biological nitrogen (N) fixation. However, the symbiotic efficiency of pigeonpea with native soil rhizobia has not been determined adequately. This study was designed to determine the variation in the N fixation ability of pigeonpea inoculated with the native rhizobia. Forty soil samples were collected from diverse locations across South Africa and used for inoculating pigeonpea seed. Each pigeonpea genotype was inoculated separately with each soil sample and raised in a nitrogen-depleted growth medium in the greenhouse. A split-plot experimental design was used in the study. Several N fixation variables of pigeonpea were measured. There was >40.0% difference in the number of nodules between genotypes ‘Ex-PP-MD-321’ and ‘Mpuma-B-Spot’ but the nodule dry weight between the two genotypes was >80.0%. In contrast, the heaviest dry shoots (0.4513 g), weighed 52.0% heavier than those that were observed for ‘Mpuma-B-Spot’. Pigeonpea showed differential N fixation ability with the nodules, suggesting that there was potential to select for optimum host × rhizobial isolate combinations for the process and to expand the production area of the crop.

Iron walnut, Juglans sigillata Dode, restricted to southwestern China, has its centre of distribution in Yunnan Province which has a varied climate, geography and rich plant diversity. Yunnan contains abundant J. sigillata germplasm. In this study, a provincial-scale set of walnut germplasm resources (14 populations comprising 1122 individuals) was evaluated for genetic diversity based on 20 simple sequence repeat (SSR) loci. The number of SSR alleles per locus ranged from 7 to 27, with an average of 17.55. Mean allelic richness and mean private allelic richness ranged from 3.40 to 4.62 and 0.11 to 0.36, with average of 3.93 and 0.30, respectively. Expected heterozygosity (He) varied from 0.26 to 0.78, with an average of 0.57. Polymorphism information content ranged from 0.22 to 0.79, with an average of 0.57. Genetic differentiation (FST) was 0.05, indicating that only 5% of total genetic variability was inter-populational, a finding supported by an analysis of molecular variance and STRUCTURE analysis. Relatively high gene flow (Nm = 6.70) was observed between populations. A unweighted pair-group method with arithmetic analysis classified the 14 populations into two major groups. Mantel testing uncovered a significant correlation between geographic distance and genetic distance (r = 0.33, P = 0.04). Overall, the research revealed a moderately high level of genetic diversity in the germplasm and low genetic differentiation among populations, which showed great potential for further development and exploitation of this resource.

In order to gain an understanding of the genetic basis of traits of interest to breeders, the pea varieties Brutus, Enigma and Kahuna were selected, based on measures of their phenotypic and genotypic differences, for the construction of recombinant inbred populations. Reciprocal crosses were carried out for each of the three pairs, and over 200 F2 seeds from each cross advanced to F13. Bulked F7 seeds were used to generate F8–F11 bulks, which were grown in triplicated plots within randomized field trials and used to collect phenotypic data, including seed weight and yield traits, over a number of growing seasons. Genetic maps were constructed from the F6 generation to support the analysis of qualitative and quantitative traits and have led to the identification of four major genetic loci involved in seed weight determination and at least one major locus responsible for variation in yield. Three of the seed weight loci, at least one of which has not been described previously, were associated with the marrowfat seed phenotype. For some of the loci identified, candidate genes have been identified. The F13 single seed descent lines are available as a germplasm resource for the legume and pulse crop communities.

Triticum monococcum L. and T. boeoticum L., diploid wild relatives of bread wheat (T. aestivum L.), possess resistance to leaf rust (also known as brown rust) caused by Puccinia triticina Eriks. Haustorium formation-based resistance mechanisms (i.e. pre-haustorial and post-haustorial resistance) to leaf rust have been studied and reported in various T. monococcum accessions. In the present study, the mechanism of leaf rust resistance in T. monococcum and T. boeoticum accessions was studied using confocal laser scanning microscopy. Components of resistance studied at a histological level against leaf rust pathotypes, a Mexican pathotype (TCB/TD) and a Swiss pathotype (97512-19), indicated different types of resistance mechanism operative in the two accessions. The resistance in T. monococcum ranged from pre-haustorial resistance against 97512-19 to post-haustorial resistance against TCB/TD. The response in T. boeoticum was post-haustorial with necrosis against the two pathotypes. Pre-haustorial resistance observed in T. monococcum could serve as a potential source of durable rust resistance in wheat breeding.

The genus Malacomeles (Decne.) G. N. Jones (Rosaceae subtribe Pyrinae) represents several fruit shrubs, which is mainly distributed in North and Central America, from southern USA to Honduras and Guatemala, although the main distribution of this genus is in Mexico. Five species of the genus Malacomeles have been reported to exist in Mexico. Malacomeles is widely distributed in several mountainous ranges in Mexico, although it is unknown where most of the diversity of the Malacomeles genus is located in the country. The aim of this biogeographic study was to determine the areas of highest diversity of the genus Malacomeles in Mexico based on species richness and diversity indices in order to identify the best regions of Mexico to collect germplasm. The results indicated that most of the diversity of the genus Malacomeles is concentrated in northeast Mexico, mainly in the biogeographic province of Sierra Madre Oriental. In this province, the highest values on three biodiversity indices were found. Thus, this area can be considered as the priority area to collect the germplasm of Malacomeles. M. denticulata is the predominant and the most interesting species in Mexico from the viewpoint of collecting plant genetic resources; this species is mainly distributed in the provinces of Trans-Mexican Volcanic Axis, Mexican Plateau and Sierra Madre del Sur, where secondary priority areas to collect germplasm are located.

Landraces (LRs) are important as a source of novel alleles for crop improvement, and their conservation is therefore necessary for food security. These genetic resources have suffered continuous erosion, especially in more accessible areas. We assess the loss of Nepali rice LRs and identify the factors influencing the probability of cultivating the most dominant LR via a logistic regression model. The majority of farmers cultivate LRs and modern varieties simultaneously. However, there has been a decrease in varietal diversity and a loss of some LRs over recent years, mainly because of their low yield, their sensitivity to diseases and pests, and their late maturity. The opportunity cost of maintaining the Satha landrace is higher on irrigated farms and for those farmers specializing in niche products. On the other hand, Satha is more likely to be cultivated by large-scale farmers and by those having a religious and/or a cultural attachment to this LR. Market-based incentives are less costly than publicly funded conservation programmes, and the superior taste of some LRs may allow them to be developed as niche products. However, to achieve this, public investment is needed to generate the necessary support infrastructure. In the more accessible Terai region, there is a particular need to introduce a flexible incentive mechanism to maintain LRs and to offset the negative effect of development intervention.

Cassava brown streak disease (CBSD) remains a major threat to cassava production in Mozambique. Breeding for CBSD resistant varieties that are also preferred by farmers is an integral part of managing the disease. The main objective of the study was to determine the genetic relationship between farmer-preferred varieties from Mozambique with those from Tanzania whose resistance to CBSD is known and some of which are being used as parents in quantitative trait loci (QTL) detection studies. To achieve this, 103 genotypes collected from farmers’ field in three provinces of Mozambique were genotyped together with five varieties from Tanzania whose CBSD response is well known. Thirty-five single nucleotide polymorphism (SNP) markers with a high minor allele frequency in East African landraces were used. Results indicated that seven Mozambican genotypes were genetically similar to either one of the four Tanzanian CBSD resistant genotypes while Xino Nn'gole was genetically identical to Namikonga a CBSD resistant variety, based on the SNPs used here. Little genetic differentiation was observed in cassava between provinces, with the majority of genetic variation distributed within individual genotypes (98%) rather than among provinces (2%). Both observed (Ho) and expected (He) heterozygosity in three provinces were generally high (Ho = 0.496) and (He = 0.455). There is a high likelihood that the eight genotypes similar/identical to those from Tanzania may share the same QTL associated with CBSD resistance thus should be further evaluated for agronomic traits as well as response to CBSD.

To preliminarily evaluate the genetic diversity of the Iranian diploid Triticum L. gene pool, in this study, a total of 176 individuals belonging to T. monococcum L. ssp. aegilopoides (Link) Thell. and T. urartu Thum. ex Gandil. were pre-screened using single-strand conformation polymorphism (SSCP) analysis of the Acc-1 and Pgk-1 loci. A selected set of 76 DNA samples corresponding to the observed SSCP variants were sequenced for both loci and evaluated for nucleotide diversity associated with the taxonomic groups and geographical regions. We found three haplotypes, including one that was new for Iran, at each locus. Population structure and analysis of molecular variation results proved that the collection evaluated could be genetically divided into two distinct groups, which to a great extent was in accordance with the taxonomic classification. A genetic leakage from T. monococcum ssp. aegilopoides into T. urartu was observed during structure analysis, which was inferred on the basis of occasional outcrossing, despite their inbreeding nature. The results revealed that there was no variation within the populations belonging to T. urartu, while a meaningful variation was found between the geographical regions for T. monococcum ssp. aegilopoides. The median-joining networks revealed a conflict between morphology and haplotype variation, which was interpreted on the basis of introgressive hybridization, recombination signature and rapid speciation. In conclusion, we suggest that SSCP analysis is a useful tool in regions where thorough sequencing of an enormous number of DNA samples is time consuming and not affordable.

Bamboo shoots and leaves are valuable food sources for both humans and livestock. The USDA-ARS NPGS (National Plant Germplasm System) collections hold 93 bamboo species in 20 genera. Total leaf protein, amino acid composition and elemental content for these important genetic resources had never been quantified. Lack of nutrition information hinders germplasm utilization. The above-mentioned nutritional traits were evaluated from these 93 species in this study. Leaf protein content among bamboo species ranged from 8.12 to 16.33% with an average of 12.84%. This average was higher than 9.0% observed for switchgrass leaves, but considerably lower than 32.48% in cassava leaves. For 18 quantified amino acids, there was more than a twofold variation among the samples evaluated. For 12 quantified mineral elements, there was significant variability from the low end (4.2-fold, 2.27–9.52 mg/g calcium; 4.4-fold, 56.17–246.43 µg/g sodium) to the high end (61.5-fold, 17.67–1087.0 µg/g manganese; 40.8-fold, 42.0–1713.5 µg/g aluminium). Due to their variability in leaf nutritive value, bamboo species should be carefully chosen when they are used as a feedstock. The results from this study will be useful for the bamboo industry, producers and consumers.