Journal articles: 'Germplasm resources, Plant – Evaluation' – Grafiati (2024)

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The identification and evaluation of tea [Camellia sinensis (L.) O. Kuntze] germplasm resources are of great significance for tea plant breeding. In recent years, various methods, such as morphology, biochemistry, molecular markers, and sensory evaluation, have been used to evaluate the tea germplasm resources. However, the evaluation of tea germplasms based on metabolomics is rarely reported. In this study, we first measured the main agronomic characters and biochemical components of tea young shoots in spring, and then analyzed the metabolic profiles using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography with tandem mass spectrometry (LC-MS/MS). The results indicate that tea germplasm accessions QN3 and QN38 had excellent agronomic traits with early germination and high yield compared with HM. The biosynthesis of flavonoids in young shoots of QN3 was more vigorous, especially for the biosynthesis of epigallocatechin gallate (EGCG) and epicatechin gallate (ECG). Accession QN3 had highest content of luteoloside, myricetin and rutin, whereas QN38 had highest content of most amino acids. On the basis of sensory quality evaluation, accession QN3 and QN38 all had higher total quality scores. By using these approaches, we found that QN3 and QN38 are excellent breeding materials with high yield and high quality for making green teas. We also believe that the evaluation system constructed by the approaches described here is suitable for the identification of tea germplasms.

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The United States' National Plant Germplasm System (NPGS) is responsible for the acquisition, preservation, evaluation and distribution of plant genetic resources in the form of seed and clonal germplasm. In order to operate more effectively, the NPGS established a network of 40 Crop Advisory Committees (CACs) to provide analysis, data, and advice about germplasm within a crop or group of related crops of current or future economic importance. CACs are composed of Federal, State and industry scientists representing a variety of agricultural disciplines and geographic areas of importance to the crop. The committees are involved in a variety of activities including: 1) Developing crop descriptors for the collection of standardized characteristic and evaluation data, 2) Determining priorities for germplasm acquisition, evaluation and enhancement, 3) Advising curators on maintenance techniques, and 4) Developing special reports on the status of genetic resources for their crop(s). Twenty-four of the CACs are concerned with horticultural crops.

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Job’s tears (Coix lacryma-jobi L.) is an ancient plant with high nutritional and medicinal value. In this study, using 11 Chinese germplasm resources for Job’s tears, we examined genetic differences among the germplasms and differences in the in vitro antioxidant activities of coixan, and sought to identify inter-relationships between these two variables. We found that the intraspecific conservation of DNA sequences was high, with ITS regions and cpDNA trnL-F and trnH-psbA non-coding sequences showing no sequence variation, whereas the GBSSI gene showed a certain degree of variation among the different germplasms. EST-SSR analysis also revealed a relatively low level of genetic diversity among the germplasms. Coixan was shown to be an efficient antioxidant, and among the germplasms examined, the LNYX, FJPC, and AHBZ had the highest antioxidant activities. However, none of the four in vitro antioxidant activity indices we assessed were significantly correlated with the geographical origin of the germplasm (latitude and longitude); however, one of them was significantly associated with genetic diversity. Although the factors affecting the antioxidant activity of coixan are complex, the role of heredity should not be ignored. Our findings have implications for the scientific evaluation, identification, and sustainable utilization of the germplasm resources for Job’s tears.

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The National Plant Germplasm System (NPGS) is responsible for the acquisition, maintenance, evaluation, and distribution of genetic diversity of crop plants important to U.S. agriculture. The NPGS collections currently include more than 425,000 accessions representing more than 8000 species. The curators of the individual active collections face many challenges, including preserving the maximum amount of genetic diversity in active collections, encouraging the use of the germplasm in the collections, and operating with limited resources. During the past 5 years, the NPGS curators and the 40 Germplasm Committees have been evaluating how core subsets can help in meeting these challenges. A set of general guidelines and procedures for developing core subsets has been developed.

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The present work compiles the results of three-year expeditions organized between 2011 and 2013 aimed at plant crop collection in the area of Lithuania, an Eastern European country. Accessions of fruit trees, vegetables, cereals, forage, industrial, fibrous, medical, and spice crops as well as accompanying segetal plants were collected in 5 ethnographic regions of Lithuania. In total, 1010 samples of seeds, bulbs, and plant grafts were obtained. The majority of the collected samples belonged to the Cucurbitaceae, Fabaceae, Solanaceae, Alliaceae, and Rosaceae families. The accessions were described and deposited in the long-term storage in Lithuanian and Polish Gene Banks. Almost all collected cucumbers, pumpkins, squashes, and oat plants were morphologically characterized in field experiments. Cucurbita pepo accessions showed high morphological diversity, while limited diversity of cucumber accessions was observed. Oat plants were characterized by high morphological diversity and resistance to diseases present in some of the investigated accessions. Further characterization of collected apple trees and other accessions is underway. Obtaining germplasm in the area of Lithuania fulfills a gap in current plant crop collections. Collected material could be valuable for pre-breeding evaluation and further breeding programs as well as the study of genetic diversity.

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Coconut (Cocos nucifera L.) is a tropical evergreen crop with high economic value. Low temperature is one of the main environmental factors that limit coconut productivity. Therefore, it is necessary and significant to research the growth trend and physiological changes of coconuts under a low temperature environment. In this study, the physiological response of 20 coconut germplasm resources is presented in an integrated perspective to provide a holistic view of the behavior of coconut trees facing cold stress under four temperature conditions (25 °C, 15 °C, 10 °C, 5 °C). It was shown that low temperature would lead to the increase of relative electrical conductivity, MDA content, soluble protein content, and proline content. In addition, the activities of defense enzymes (SOD, POD, CAT, APX) were increased to resist the cold environment. In a comprehensive analysis, it was revealed that coconut germplasms with high cold resistance, such as C2, C7, and C10 as well as POD activity, proline content, and soluble protein content, were defined as representatives for coconut cold resistance evaluation. Through the exploration of osmotic adjustment substances and defense enzymes, the breeding and quality improvement of cold-resistant coconut varieties could be promoted. As a result, understanding the physiological response and tolerance mechanisms of coconuts to low temperature stress was essential, as this perception may serve as the foundation for coconut resistance evaluation, cultivation, and breeding.

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Substantial and sustainable increases in productivity of all crops are needed to meet the predicted demand for food, feed, fibres, flowers, fuels, fun, feed-stocks and pharmaceuticals of this 21st century bio-based economy. Plant breeding is vital for protecting the yield gains made to date, and for further increasing the genetic yield potential of all crops. As a result of the Green Revolution, global productivity of the main food staples steadily rose since the 1960s. Such achievements ensued from crop genetic enhancement partnerships. They are models for illustrating partnering for exchange, evaluation, release and use of plant genetic resources worldwide. These partnerships include national agricultural research institutes and international agricultural research centres. For many decades the global wheat yield increased due to an effective International Wheat Improvement Network (IWIN), which deployed cutting-edge science alongside practical multi-disciplinary applications, resulting in the development of bred-germplasm that has improved food security and the livelihoods of farmers in the developing world. IWIN operates field evaluation trials in more than 250 locations of 100 countries for testing breeding wheat lines across many environments. The International Network for Genetic Evaluation of Rice (INGER) has become an integral component of rice breeding programmes: every year partners provide about 1000 genetically diverse breeding lines, which have been grown in about 600 experiment stations from 80 countries. The Latin American Maize Programme (LAMP) has assessed national germplasm, facilitated the exchange of genetic resources across the continent, and its core subset has been made available to encourage further use in broadening maize genetic resources. For example, the Germplasm Enhancement of Maize (GEM) project has used LAMP-selected landraces in crosses with elite temperate maize lines provided by North American private companies, to introgress useful genetic diversity into US maize germplasm, with the aim to broaden the genetic base of “corn-belt” hybrids.

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A large diversity of fruit crop accessions is maintained at the Latvia State Institute of Fruit- Growing, which consists of modern cultivars, landraces and selections from local breeding programmes, as well as germplasm that has resulted from scientific exchange and co-operation with other institutes. Presently, the germplasm collection comprises 2509 accessions of 17 fruit crops; 676 accessions are designated as national genetic resources. Conservation of germplasm itself has little value without characterisation and further utilisation of the stored plant material. To intensify these activities, DNA-based technologies have been implemented in the characterisation of germplasm. Two main groups of molecular markers have been utilised: non-specific markers and gene-specific (functional) markers, subsequently applicable for Marker Assisted Selection (MAS). Genotyping protocols based on SSR, RAPD and Methylation-sensitive amplification polymorphism (MSAP) markers have been developed for twelve fruit crops for use in plant material identification, True-to-Type verification and evaluation of genetic diversity and internal collection structure. In total, 790 accessions have been genotyped using any of the mentioned markers. These markers have been harmonised with the European cooperative programme for plant genetic resources working group (ECPGR WG) recommended sets to ensure international data exchange. Gene specific molecular markers have been applied to apple and pear (resistance to scab), strawberry (resistance to Gnomonia fragariae), sweet cherries and plums (self-incompatibility).

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There is a lack of published microsatellite data which characterizes Ribes spp. To address this, an initial study of simple sequence repeat (SSR) variation was undertaken in 41 cultivars belonging to four species of the genus Ribes to evaluate its genetic variability. The cultivars were collected in Piedmont, northwest Italy, together with one cultivar from Switzerland. Twenty SSRs were screened for amplification and polymorphism. Seven failed to amplify, and therefore the remaining 13 were selected and used to fingerprint all the cultivars. Microsatellite analysis resulted in the identification of 38 genotypes, suggesting the existence of possible clonal genotypes and synonyms. Among the cultivars analyzed, two tetraploid accessions were found. The evaluation of genetic variability in Ribes is of fundamental importance for future nutritional breeding programs and to preserve genetic resources, as cultivar characterization permits better management of plant collections.

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Security of any country as well as the whole world can be ensure through the conservation of germplasm since they are genetic resources that can be used to prolong a population of an organism. Plant genetic resources (PGR) are the foundation of agriculture as well as food and nutritional security. The ICAR-NBPGR is key institution at national level for management of PGR in India under Indian Council of Agricultural Research (ICAR), New Delhi. India being rich in both flora and fauna germplasm diversity also have challenge of protecting its natural heritage. At the same time, we also have mutually beneficial strategies for germplasm exchange with other countries. The National Bureau of Plant Genetic Resources (NBPGR) activities include PGR exploration, collection, exchange, characteri- zation, evaluation, conservation and documentation. It also perform the responsibility to carry out quarantine of all imported PGR. NBPGR collects and acquires germplasm from various sources, conserves it in the Genebank, characterizes and evaluates it for different traits and provides ready material for breeders to develop varieties for farmers. At present, the National Genebank conserves more than 0.45 million accessions. NBPGR is responsible for identifying trait-specific pre-adapted climate resilient genotypes, promising material with disease resistance and quality traits which the breeders use for various crop improvement programmes. The prime focus area of research of NBPGR at present is is on characterization of ex situ conserved germplasm and detailed evaluation of prioritized crops for enhanced utilization. identification of novel genes and alleles for enhanced utilization of PGR; identification and deployment of germplasm/landraces.

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This paper is a tribute to the legacy of Dr Clive Francis, who directly and indirectly collected >14 000 accessions across 60 genera of pasture, forage, and crop species and their wild relatives around the Mediterranean basin, Eastern Africa, and Central and South Asia from 1973 to 2005. This was achieved by a collaborative approach that built strong interactions between disparate organisations (ICARDA, VIR, CLIMA, and Australian genebanks) based on germplasm exchange, conservation and documentation, capacity building, and joint collection. These activities greatly strengthened Australian pasture, forage, and crop genebanks, and led to widespread germplasm utilisation that has waned in the last 5 years, reflecting changing priorities among industry funding bodies and research providers. This situation must be reversed, given the pivotal role genetic resource collections must play to broaden the genetic and adaptive base of plant breeding, to meet the challenge of feeding an increasing population in a depleting resource base. Because the use of germplasm subsets that facilitate phenotyping will stimulate wider utilisation of genetic resources, we discuss the application of core collection and germplasm selection through habitat characterisation/filtering in Australian collections. Both are valid entry points into large collections, but the latter has the advantage of enabling both trait discovery and investigation of plant adaptation, and because it is based on a priori hypothesis testing, it increases understanding even when the trait of interest is not identified.

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Rocket (Eruca spp. and Diplotaxis spp.) is widely cultivated as a green vegetable in Mediterranean countries, Europe, United States and Brazil, but few rocket cultivars are available and limited variety selection has taken place. Plant genetic resources and germplasm are fundamental sources for plant breeding, and the assessment of the genetic diversity among germplasm accessions is useful to facilitate the more efficient use of plant genetic resources. The objective of this study was to characterize phenotypic diversity and relationships among genotypes of Eruca and Diplotaxis originating from 11 countries across three regions (Europe, Africa and Asia). Principal component analyses explained over 85% of total variation for 51 qualitative and quantitative agromorphological traits. Cluster analyses divided the accessions into five major clusters according to plant traits, siliqua properties and geographical origin of genotype with a few exceptions. These findings indicate a number of useful traits in the gene pool and a wide range of phenotypic variation that provides a good source of diversity for use in modern Eruca breeding programmes.

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AbstractMucuna pruriens(L.) DC is a tropical legume cover crop with promising nutritional and agronomic potentials. It is also a key source of 3,4 dihydroxy-L-phenylalanine (L-Dopa) – a precursor of dopamine used in the treatment of Parkinson's disease. However, lack of well-characterized germplasm plus poor accessibility to genomic resources has hindered its breeding programs. Furthermore, the cause and effect of various biotic and abiotic stresses impacting yield is also little studied. Systematic collection and evaluation of Indian germplasm by our group revealed presence of a diverse gene pool in India that can support a variety of breeding needs. The stability of L-Dopa trait across environments examined through Genotype and environment (G × E) interaction studies, as well as feasibility check on barcoding and phylogenetic analyses based on karyotype and conserved nuclear and chloroplast genes showed promising outcome. Germplasm screening for select biotic abiotic stresses identified resilient genotypes. Advances in use of DNA markers for diversity analysis, linkage map development, tagging of genes/quantitative trait loci for qualitative and quantitative traits, and progress in genomics are presented.

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Foreground and background selections are two important aspects that need to be carefully considered by plant breeders during field selection. In this article, we used 7 disease resistance markers, including four late blight and three potato virus disease resistance gene markers, and 12 microsatellite markers to evaluate the disease resistance and genetic diversity of 76 potato cultivars in total which were collected from 15 provinces of China. The foreground selection results showed that a number of materials, clustered separately, contained more than two late blight resistance markers or pyramided late blight and virus disease resistance gene markers together. A lot of them were collected from the southwest of China. Additionally, the genetic backgrounds of all cultivars were relatively narrow and a limited number of cultivars (15.8%) contained both potato late blight and potato virus Y resistance markers. Also, only two accessions (Yunshu 103 and Lishu 7) contained both late blight and potato virus X resistance markers. In conclusion, this comprehensive evaluation of genetic resources will shed the light on potato disease resistance breeding in the future.

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The Horticulture Program at the Western Regional Plant Introduction Station is responsible for the maintenance and distribution of germplasm collections of ten crop genera. These ten genera include over 28,000 accessions of 267 species of germplasm with either food or ornamental potential. The largest collection is beans (Phaseolus, > 11,500 accessions) which includes 32 species. Large collections of the cool season food legumes include Cicer, Pisum and Lens. Smaller legume collections include Lupinus, Lathyrus, Trigonella and Vicia. Although there are fewer than 3300 accessions within these four genera, there are 134 species represented. Although smaller in number of accessions, the Allium and Lactuca collections are extensively utilized for food and ornamental development programs. Associated with the curation and seed maintenance of these crops is a seed-borne virus eradication program, the development of core collections, and expansion of the evaluation data and other documentation into the Germplasm Resources Information Network.

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AbstractRosa x odorata (sect. Chinenses, Rosaceae) is an important species distributed only in Yunnan Province, China. There is an abundance of wild variation within the species. Using 22 germplasm resources collected from the wild, as well as R. chinensis var. spontanea, R. chinensis ‘Old Blush’ and R. lucidissima, this study involved morphological variation analysis, inter-trait correlation analysis, principal component analysis and clustering analysis based on 16 morphological traits. This study identified a high degree of morphological diversity in R. x odorata germplasm resources and the variation coefficients had a distribution range from 18.00 to 184.04%. The flower colour had the highest degree of variation, while leaflet length/width had the lowest degree of variation. Inter-trait correlation analysis revealed that there was an extremely significant positive correlation between leaflet length and leaflet width. There was also a significant positive correlation between the number of petals and duration of blooming, and the L* and a* values of flower colour were significantly negatively correlated. Principal component analysis screened five principal components with the highest cumulative contribution rate (81.679%) to population variance. Among the 16 morphological traits, style length, sepal width, flower diameter, flower colour, leaflet length and leaflet width were important indices that influenced the morphology of R. x odorata. This study offers guidance for the further development and utilization of R. x odorata germplasm resources.

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Cowpea (Vigna unguiculata L. Walp) is one of the important vegetable, grain, and fodder legume species grown in the tropics and subtropics. Cowpea is grown on small farms, and locally adapted landraces or populations are cultivated, and genetic improvements are limited by the lack of knowledge of genetic diversity of the indigenous and cultivated germplasm. Characterization and classification of diversity of the germplasm is valuable for both plant breeders and germplasm curators in the development of conservation strategies and identification of plant genetic resources. In the present study, 36 qualitative and quantitative agromorphological traits were used to characterize and assess the genetic diversity of 32 farmer preferred cowpea genotypes collected from diverse cultivated locations. Genetic variation was highly significant, and phenotypic diversity was observed for agromorphological traits. Agromorphological traits were classified by principal components analysis (PCA) into 10 components, which explained 81.18% of the total variation. PCA revealed that seed properties such as weight, diameter, width, length, eye color and immature pod pigmentation, leaf and pod color properties were the primary characteristics to discriminate cowpea genotypes. The hierarchical analysis grouped the genotypes into five clusters, and significant association was not apparent between geographic origin and agromorphological traits. The promising germplasm was identified to improve the landraces for fresh pod, grain, and fodder.

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SynopsisThe International Board for Plant Genetic Resources (IBPGR) has paid particular emphasis to SW Asia in its endeavour to collect, conserve and promote utilisation of the world's plant germplasm. This is in view of the region's rich genetic diversity in many crop plants and their weedy/wild relatives, coupled with its alarming rate of genetic erosion. Action during the past decade has focused on collecting mainly cereal and grain legume crops and their closest wild relatives within the framework of a regional programme encompassing six countries. Gene banks were also set up in these member countries to handle a full range of operations including seed storage, characterisation/preliminary evaluation and documentation. In future, emphasis will be placed on ecogeographical surveys prior to mounting collecting missions and on more characterisation/preliminary evaluation work.

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The genetic diversity of rice germplasm is the basis for increases in rice yield and quality. The collection, assessment, and protection of the genetic diversity of rice germplasm is important for achieving sustainable agriculture and assuring food security. Many underdeveloped indigenous areas have abundant and valuable rice germplasm resources. However, in-depth assessments of the genetic diversity of rice germplasm from these areas and studies related to protecting these traditional cultures are not available. In this study, from 2005 to 2016, the authors have conducted in-depth evaluation of the genetic diversity of Kam fragrant glutinous rice germplasm resources in southeast Guizhou by using multidisciplinary comprehensive methods such as ethnobotany, cultural anthropology, and modern molecular markers. In total, 376 Kam fragrant glutinous rice samples from 42 villages in the Dong community in southeast Guizhou were collected. Agronomic traits of panicles were complex and exhibited diversity. Some varieties had good disease resistance and adaptation to cold and wet climates. The Dong people named the Kam fragrant glutinous rice varieties by using seven elements, including diverse traits, growth environment, and origin. Traditional folk classification, in addition to morphology and biological analysis using molecular markers, indicates that Kam fragrant glutinous rice includes 91 varieties. Kam fragrant glutinous rice comprises a very high number of varieties, most of which are japonica-type and exhibit a high level of genetic diversity. The traditional folk classification of Kam fragrant glutinous rice by the Dong community is consistent with the biological classification. The traditional naming of Kam fragrant glutinous rice provides an important reference for understanding its genetic diversity. The high level of genetic diversity in Kam fragrant glutinous rice is not only related to the natural environment of the area but also tightly linked with the abundant and diverse Dong ethnic traditional cultures, which has led to protection of Kam fragrant glutinous rice’s genetic diversity.

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Purpose, requirements, and application of morphological descriptors for use in a sugarcane germplasm collection are reviewed. Such descriptors could be used to verify the identity of cultivars, and as a measure of genetic distance. Verification of cultivar identity is essential in routine plant breeding and associated research. Genetic distance estimation would enable a better usage of available genetic resources. Morphological characters are perhaps more reflective of agronomic performance and they provide a broader sampling of the genome than molecular techniques. Statistical evaluation of characters for adoption as descriptors differs from most taxonomic studies because the population is hybrid and open, with accelerated genetic drift. The various discriminant analyses provide the optimal character selection technique. Variance components of individual characters should also be analysed to enable character improvement. Different ways of incorporating descriptor usage into the plant breeding program are discussed.

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Plant viruses pose a threat to the acquisition, maintenance and distribution of lupin germplasm (genusLupinus, familyFabaceae). The availability of sufficient quantities of healthy and virus-free seeds from maintained lupin collections is mandatory for conducting lupin research. The objective of this research was to determine which lupin species were potentially infected with potyviruses (presumably seed-borne) upon germination in the greenhouse. The procedure for screening lupin seedlings in the greenhouse for potyviruses incorporated enzyme-linked immunosorbent assay followed by elimination or segregation of infected seedlings from the population before transplantation into the field plots for regeneration and accession characterization. None of the accessions in this evaluation had been tested previously for virus. From 2002 to 2005, 15 perennial (30 accessions) and 6 annual lupin species (213 accessions) were evaluated on site at the Western Regional Plant Introduction Station in Pullman, WA, USA. While none of the greenhouse perennial seedlings tested positive for potyvirus, seedlings in three annual species (Lupinus albus,Lupinus angustifoliusandLupinus luteus) were infected by potyviruses, presumably by seed transmission. Future testing may focus on the annual species, thus saving limited germplasm maintenance resources.

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Echinacea is becoming a well-established, high-value crop, both as an ornamental and a dietary supplement. A comprehensive collection of Echinacea germplasm is conserved by the USDA-ARS North Central Regional Plant Introduction Station (NCRPIS) in Ames, Iowa, and is available via seed distribution for research and educational purposes (ars-grin.gov/npgs). Representing all nine species collected throughout their respective North American geographic ranges, the Echinacea collection includes 179 accessions. Extensive morphological characterization data associated with this collection have been compiled and are available to researchers on the Germplasm Resources Information Network (GRIN) database to aid in selection criteria. The collection has been used extensively for various research projects, ranging from ornamental breeding studies to HPLC analyses of metabolites of interest to the phytopharmaceutical industry. This poster will summarize the Echinacea collection conserved at the NCRPIS, including a list of available accessions by species, illustrations of seed, and control-pollinated cage propagation methods; and facilities utilized for seed cleaning, testing, and storage. In addition, instructions on how to use the GRIN database to view evaluation data and acquire germplasm will be provided.

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Indiscriminate growth can lead to germplasm collections that are too large to maintain, too large to use, or both. Curators' budgets do not often increase with collection size, so conservation and utilization activities are hindered. Maintenance of genetic integrity in large collections is practically impossible. Evaluation is restricted to easily-observed traits, potentially limiting utilization. One strategy to improve management of large collections is the core collection concept, proposed by O.H. Frankel in 1984 and subsequently expounded by A.H.D. Brown. It establishes one subset of accessions, the core, selected to represent “with a minimum of repetitiveness, the genetic diversity of a crop species and its relatives”. The other subset, the reserve, includes all accessions not in the core. Both subsets are conserved according to the highest standards feasible, but the core receives priority for characterization and evaluation to facilitate use and provide subsequent directed access to the entire collection. Use and abuse of the core concept will be discussed, including: definition of terms, genetic and statistical assumptions, and practical implementation.

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Germplasm of 153 flax (Linum usitatissimum) accessions from 24 countries held at Plant Gene Resources of Canada (PGRC) was evaluated for resistance to fusarium wilt (Fusarium oxysporum), anthracnose (Colletotrichum lini) and pasmo (Septoria linicola). The screening was conducted at the All-Russian Flax Research Institute (VNIIL) at Torzhok, Russia, over 3 years for fusarium wilt and anthracnose, and over 2 years for pasmo. A disease severity index ranging from 0% (no infection) to 100% (heavy infection) was calculated based on observations after artificial inoculation with the pathogens in the greenhouse (fusarium wilt) or in field nurseries (anthracnose and pasmo). The average disease severity index for fusarium wilt was 56.6 ± 34.4% (range 0–100.0%), for anthracnose 59.8 ± 8.1% (range 43.8–83.9%) and for pasmo 74.2 ± 11.8% (range 27.3–100.0%). The variation of disease severity indices among the years and within each accession was highest for fusarium wilt. Higher than average resistance for all three diseases was found in accessions from East Asia, while germplasm from the Indian subcontinent showed considerably lower than average resistance. Germplasm from North America and South America (mostly linseed) displayed above average resistance to fusarium wilt, while European accessions (mostly fibre flax) showed lower than average resistance to this disease. The different resistance levels reflected the improvements made by plant breeding and differences in the environments under which the germplasm accessions evolved. Accessions with potential use in linseed and fibre flax breeding were identified.

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Global warming and worsening environmental problems have worsened the heat resistance of peony and difficult maintenance and management. The high temperature stress caused by the environment has become an important environmental factor for the growth and development of peony. The article summarizes the morphology, yield, physiological and biochemical indicators and research status of peony under high temperature stress; summarizes the research status of peony heat tolerance evaluation index screening, germplasm heat tolerance evaluation and heat-resistant peony breeding, in order to promote tolerance Selection and breeding process of hot peony germplasm resources. At present, related researches on peony mainly focus on pharmacological effects and germplasm resources. The physiological mechanism of high temperature and breeding of heat-resistant varieties of peony are relatively lagging behind. In-depth study of the physiological mechanism of high temperature in peony combined with multi-omics will help to adopt technical measures to improve the heat tolerance of high plants and reduce heat damage, so as to speed up the selection and breeding of heat-resistant peony germplasm, and meet the survival and medicine of peony in harsh environments. Use and other needs.

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Wild soybean germplasm is distributed widely in China, particularly in Heilongjiang Province. In this study, 242 wild soybean accessions from four agricultural divisions in Heilongjiang Province were evaluated based on six qualitative and eight quantitative traits. Results showed that a large amount of variation occurred in these evaluated traits. Abundant qualitative traits included the wild type (78.51%), purple flowers (90.50%), needle leaf (39.26%), black seed (83.88%), brown hilum (52.07%), and mud film (87.60). Results of multivariate analysis based on quantitative traits showed that 100-seed weight, seeds weight per plant, number of seeds per plant, number of effective pods, and number of invalid pods were significantly different among samples (p < 0.05). A total of 27 germplasms were screened. Cluster analysis identified the 242 accessions into two groups, not following the geographical distribution pattern, with rich wild soybean resources revealed in the northern site. The present study indicated that wild soybean in Heilongjiang Province should be conserved in situ. The rich genetic diversity revealed in soybeans of different sites in Heilongjiang Province suggested its significant potential utilization in genetic improvement and breakthrough for soybean breeding. This information will help to exploit and conserve wild soybean accessions in Heilongjiang Province.

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Wild germplasm can be classified as the raw material essential for crop improvement. Introgression of wild germplasm is normally used in breeding to increase crop quality or resilience to evolving biotic and abiotic threats. Here, we explore the potential of introgressing Vaccinium elliottii into commercial blueberry germplasm. Vaccinium elliottii is a wild diploid blueberry species endemic to the southeastern United States that possesses highly desirable and economically important traits for blueberry breeding such as: short bloom to ripe period, adaptation to upland sandy soils, disease resistance, firmness, and pleasant flavor. To examine the potential of hybridization, we evaluated populations of interspecific hybrids across multiple stages of breeding (i.e., F1, F2, and backcrosses) in two crop seasons. We used our extensive pedigree data to generate breeding values for pre-breeding blueberry hybrid populations. Hybrid performance was evaluated considering fitness (i.e., plant vigor and plant height) in addition to evaluating six fruit-quality and marketable-related traits (i.e., size, firmness, acidity, soluble solids, weight, and yield). Overall, F2 and backcrosses rapidly achieved market thresholds, presenting values not significantly different from commercial blueberry germplasm. Our results confirmed the potential of exploiting the high genetic variability contained in V. elliottii for interspecific hybridization. Additionally, we developed germplasm resources that can be further evaluated and utilized in the breeding process, advancing selections for fruit quality and environmental adaptation.

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SUMMARYStripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a major wheat disease that can inflict yield losses of up to 70% on susceptible varieties under favourable environmental conditions. The timely identification of plant genetic resources likely to possess novel resistance to this disease would facilitate the rapid development of resistant wheat varieties. The focused identification of germplasm strategy (FIGS) approach was used to predict stripe rust resistance in a collection of wheat landraces conserved at ICARDA genebank. Long-term climate data for the collection sites, from which these accessions originated and stripe rust evaluation scores for one group of accessions were presented to three different non-linear models to explore the trait×collection site environment interactions. Patterns in the data detected by the models were used to predict stripe rust resistance in a second and different set of accessions. The results of the prediction were then tested against actual evaluation scores of the disease in the field. The study mimics the real scenario where requests are made to plant genetic resources curators to provide accessions that are likely to possess variation for specific traits such as disease resistance.The models used were able to identify stripe rust-resistant accessions with a high degree of accuracy. Values as high as 0·75 for area under the curve and 0·45 for Kappa statistics, which quantify the agreement between the models’ predictions and the curator's disease scores, were achieved. This demonstrates a strong environmental component in the geographic distribution of resistance genes and therefore supports the theoretical basis for FIGS. It is argued that FIGS will improve the rate of gene discovery and efficiency of mining genetic resource collections for adaptive traits by reducing the number of accessions that are normally required for evaluation to identify such variation.

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Forty Chinese sorghum landraces maintained by the USDA-ARS Plant Genetic Resources Conservation Unit, Griffin, GA were evaluated for ergot resistance at the Texas A&M Research Farm, College Station, Texas, during the 2005 and 2006 growing seasons. The male sterile line, ATx623, was included as a susceptible control and three IS8525 derived lines were included as resistant controls. The disease infection level was low in the susceptible check in 2005 due to unfavorable environmental conditions, but the majority of the Chinese accessions showed a higher level of tolerance than the resistant controls and in contrast, infection severity was high in 2006. The IS8525 resistant controls averaged 25% infection compared to an average infection of 18% for the 40 Chinese accessions. Four Chinese accessions, PI63923, PI511832, PI610749, and PI610688, recorded less than 10% ergot infection and thus, these four accessions may possess genes for ergot resistance. Further research is underway to evaluate these accessions under multi-environments to confirm resistance and to determine if the resistance is associated with pollination characteristics. Accepted for publication 19 February 2008. Published 19 May 2008.

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Genetic relationships among 970 cucumber (Cucumis sativus L.) plant introductions (PIs) in the U.S. National Plant Germplasm System (NPGS) were assessed by observing variation at 15 isozyme loci. Allozyme frequency data for these PIs were compared to allozyme variation in heirloom and modern (H&M) cultivars released from 1846-1985 (H&M cultivars; 178 accessions), and experimental commercial (EC) germplasm (EC germplasm; 82 accessions) in use after 1985. Multivariate analysis defined four distinct groups of accessions (Groups A-D), where Group A consisted of PIs received by the NPGS before 1992, Group B contained PIs from India and China obtained by NPGS after 1992, Group C consisted of EC germplasm, and Group D contained H&M cultivars. Morphological, abiotic stress (water and heat stress tolerance) and disease resistance evaluation data from the Germplasm Resources Information Network (GRIN) for the PIs examined were used in conjunction with estimates of population variation and genetic distance estimates to construct test arrays and a core collection for cucumber. Disease resistance data included the evaluation of angular leafspot [Pseudomonas lachrymans (E.F. Smith) Holland], anthracnose [Colletotrichum lagenarium (Ross.) Ellis & Halst], downy mildew [Pseudoperonospora cubensis (Berk. & Curt) Rostow], rhizoctonia fruit rot (Rhizoctonia solani Kuhn), and target leafspot [Corynespora cassiicola (Berk. & Curt) Wei] pathogenicity. The test arrays for resistance-tolerance to angular leafspot, anthracnose, downy mildew, rhizoctonia fruit rot, target leafspot, and water and heat stress consisted of 17, 16, 17, 16, 17, 16, and 16 accessions, respectively. The core collection consisted of accessions in these test arrays (115) and additional 32 accessions that helped circ*mscribe the genetic diversity of the NPGS collection. The core collection of 147 accessions (115 + 32) represents ≈11% of the total collection's size (1352). Given estimates of genetic diversity and theoretical retention of diversity after sampling, this core collection could increase curatorial effectiveness and the efficiency of end-users as they attempt to identify potentially useful germplasm.

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Forage breeding is essential for animal production, and its effectiveness depends on available genetic diversity. However, breeding is challenged when there is limited evaluation of genebank accessions. Predictive characterisation based on ecogeographic information is a promising approach to address the urgent need to expedite evaluation of target traits in existing collections of forage genetic resources. Using white clover (Trifolium repens L.) as an example, we applied predictive characterisation to model the expression of cyanogenesis, an important process related to the generation of anti-quality compounds. Data on genebank accessions and other population occurrences were divided into two subsets, one including accessions that had been evaluated for this trait, and the other with those that had not. The occurrence sites of the records with the best geo-referencing quality were characterised ecogeographically. The cyanogenesis trait was predicted using the calibration method, in which some selected ecogeographic variables were used as independent variables. Thus, we identified 470 populations with high probability of being acyanogenic. A small sample of populations (18 accessions) was evaluated to ratify the usefulness of this approach. Seventeen of the evaluated accessions showed a complete acyanogenic response and one showed 95% acyanogenic plants. Our study also expanded the areas previously rated as highly acyanogenic. In conclusion, our results contribute in a predictive way and with minimum cost to increase the knowledge of wild populations and genebank accessions in relation to a target trait. This facilitation in the generation of evaluation data may encourage greater investment in forage plant breeding and boost germplasm utilisation.

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Castor (Ricinus communis L.) is an important non-edible oilseed crop that can potentially be used as feedstock for biodiesel production. There are 1033 accessions in the United States Department of Agriculture (USDA) castor germplasm collection. The range of oil content in these accessions has never been surveyed. For exploiting castor as a feedstock for biodiesel production, the entire USDA castor collection was procured from the National Plant Germplasm System (Germplasm Resources Information Network) and the oil content was measured with nuclear magnetic resonance. The variation of oil content among all castor accessions ranged from 37.2 to 60.6% with an average of 48.2%. One hundred seed weights were determined and seed-coat colour was also recorded from each accession. One hundred seed weight ranged from 10.1 to 73.3 g with an average of 28.3 g. There was a significant correlation between seed weight and oil content but the correlation value was low (r = 0.1572, P < 0.0001). Fifty accessions with a wide range of oil content were selected to be field grown for further evaluation. The results obtained from this survey will be useful for castor breeders seeking germplasm accessions with high oil content in the collection.

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This article focuses on advances in both basic and applied research on soybean germplasm resources collected from China and dispersed to the world. Many landraces developed over the course of the 4500 years since its domestication in the Huangdi period. Systematic germplasm collection was begun in the early 20th century by Professor Shou Wang, and since then over 170,000 accessions have been conserved worldwide. Evaluation with respect to key morphological characteristics, pest resistance, abiotic stress tolerance and nutritional quality attributes has been widely carried out. In addition, genetic diversity has been assessed at the DNA level, and used to establish core collections for both cultivated (Glycine max) and wild (Glycine soja) soybean. Some core sets have targeted the most used parental lines, and others have focused on specific traits, such as resistance to the soybean cyst nematode or to soybean mosaic virus, or enhanced phosphorus use efficiency. The recent acquisition of the soybean genome sequence should accelerate the utilization of not only the Chinese soybean germplasm collection, but also those maintained elsewhere in the world.

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Genetic resources of temperate berry crops were collected 7 to 27 July 2004 in Hokkaido, Japan, under a bilateral agreement between the United States and Japan. This expedition was a collaborative effort between the United States Department of Agriculture (USDA), the Japanese Ministry of Agriculture, Forestry and Fisheries (MAFF), the University of New Hampshire, and Akita Prefectural College of Agriculture, Japan. Additional assistance was provided by the Hokkaido Governmental Plant Genetic Resources Center, several Forest Research Stations of the Hokkaido University, and private botanists. The expedition obtained 100 accessions encompassing eight genera and 29 species. In all, 84 seedlots, and 23 plants were obtained. The genera collected included: Actinidia, Fragaria, Lonicera, Morus, Ribes, Rubus, Sambucus, and Vaccinium. Plant and seed accessions from this trip are preserved and distributed from the USDA ARS National Clonal Germplasm Repository in Corvallis, Ore., and from MAFF. The target genus for this expedition was Fragaria, so the trip was planned for July. Multiple samples of the two Japanese diploid strawberry species, Fragaria iinumae Makino and F. nipponica Makino (synonym = F. yezoensis H. Hara) were obtained during their prime ripening time. Ribes, Rubus, and Vaccinium fruits ripened later in the summer, but were collected when fruit were observed. Unfortunately, seeds of some of these accessions proved to be immature or nonviable upon extraction. We suggest that expeditions to collect these genera should be planned for late August. Morphological and molecular evaluation of collected germplasm is underway at the USDA ARS Corvallis Repository and at the University of New Hampshire.

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Soybean rust, caused by Phakopsora pachyrhizi Syd. & P. Syd., is one of the most destructive diseases of soybean [Glycine max (L.) Merr.] worldwide. To identify sources of resistance to domestic soybean rust fungus populations for plant breeding, our strategy has been to evaluate soybean lines that were previously identified as resistant to foreign isolates. In this study, two sets of plant introductions (PI) were evaluated using P. pachyrhizi urediniospores collected in Mississippi in 2006. The first set of PIs contained 10 lines previously identified as resistant in Paraguay, four PIs with known single genes for resistance to P. pachyrhizi, and Freedom and Williams 82 as susceptible checks. The second set included 17 lines that were selected based on information from Germplasm Resources Information Network (GRIN) and susceptible Williams 82. PI567102B was one of the most resistant lines to a Mississippi bulk isolate of P. pachyrhizi with the lowest severity rating, no sporulation, and red-brown lesion type. Accepted for publication 25 April 2009. Published 15 June 2009.

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The continuous increase in the world population and the associated food demands in the wake of climate change are pushing for the development and cultivation of climate-resilient crops that are able to efficiently use natural resources. Proso millet (Panicum miliaceum L.) might be a promising candidate crop thanks to its heat stress resistance and its limited water demand. To date, one of the most important strategies to increase grain yield and to improve other agronomic important traits is through an efficient breeding program based on a wide genetic variability of parental germplasm. In this study, we evaluated the agronomical traits of a world collection of 80 P. miliaceum accessions. The entire collection was evaluated over a 2 year field experiment under Mediterranean pedoclimatic conditions, which exhibited a wide range of variability for plant height (25–111 cm), grain yield (842–3125 kg ha−1), total dry biomass (2767–10,627 kg ha−1), harvest index (HI; 0.25–0.35), Growing Degree Days (GDDs; 581–899), and days to maturity (80–111 d). A non-parametric multivariate analysis of variance (Np-MANOVA) analysis indicated that GDDs to flowering, grain yield, total dry biomass, days to maturity, plant height, and seed yield per plant were useful parameters to differentiate the germplasm accessions. High heritability (>0.60) was observed in both years for plant height, leaf number, basal tiller, seed yield per plant, 100-seed weight, GDDs to flowering, and days to maturity. Grain yield, total dry biomass, and HI reported moderate heritability (0.30–0.60). The findings reported in the present study may provide valuable information that could support researchers in breeding programs to develop high grain-yielding accessions.

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Successful development of new sorghum cultivars and hybrids to ensure sustainable production depends largely on the availability of genetic resources with desirable traits such as pest resistance. Our recent research has focused on improvement of crop protection against greenbugs using the worldwide germplasm collection and genomics-based approaches. First, we conducted the systematic evaluation of a worldwide germplasm collection in order to identify new sources of greenbug resistance. Twenty-one resistant lines were identified, which offered new sources of resistance to sorghum breeding. Molecular markers used to assess the genetic diversity among those resistant lines suggested relatively diverse resistant sources in the sorghum germplasm collection. More recently, a mapping project was executed to associate the resistance genes with sorghum chromosomes. The mapping data indicated one major and a minor quantitative trait loci reside on chromosome 9 and are responsible for resistance to greenbug. In addition, cDNA microarrays were used to monitor greenbug-induced gene expression in sorghum plants. This study has developed a transcriptional profile for sorghum in response to greenbug attack, which provides us with useful molecular information for discovery of greenbug resistance genes and a better understanding of the genetic mechanisms controlling host defences in sorghum.

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AbstractTomato is injured by low doses of 2,4-D, dicamba, quinclorac, and glyphosate. New crop varieties resistant to 2,4-D and dicamba are likely to increase use of these herbicides and may increase drift problems. There is a diverse germplasm of tomato available that includes wild relatives known to be tolerant to numerous biotic and abiotic stresses. A greenhouse and field study was conducted to investigate auxin tolerance in three wild tomato accessions (TOM199, TOM198, and TOM300) and compare them with two commercial tomato cultivars (‘Money Maker’ and ‘Better Boy’). Auxin herbicides, which included 2,4-D, dicamba, and quinclorac, were applied at doses of 11, 3, and 39 g ae ha−1, respectively. Visible injury ratings of each accession for each herbicide treatment were recorded at 7, 14, 21, and 28 d after treatment (DAT) on a 0% to 100% scale. Results indicate that all three wild tomato accessions exhibited less than 15% injury compared with 100% injury for two commercial cultivars after application of dicamba. The three wild accessions (TOM199, TOM198, and TOM300) did not show any significant reduction in plant height compared with nontreated plants. At 28 DAT, plant heights of TOM199, TOM198, and TOM300 were 25, 25, and 28 cm when treated with dicamba and 31, 30, and 31 cm nontreated, respectively. Based on these results, the identified lines can serve as a genetic resource for developing herbicide-tolerant tomato, thus minimizing or eliminating the negative impacts of drift from nonlabeled herbicides tested in this project.

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AbstractComprehensive screening of rice (Oryza sativa L. subsp. japonica Kato) germplasm resources with different nitrogen (N) efficiency levels is effective for improving N use efficiency (NUE) while reducing pollution and providing high quality, yield, and efficiency agriculture. We investigated 14 indices of 38 varieties under three N application levels to assess differences among genotypes. Rice varieties were classified for screening and identifying N efficient. Descriptive statistical analysis results indicated significant differences in relative yield, and also in NUE indices (agronomic utilization rate and partial productivity of N fertilizer). The genotype main effects and genotype–environment interaction effects (GGE) biplot analysis was used to evaluate suitable varieties, compare the stable and high yield capabilities of different varieties, find the ideal variety, and describe the correlation, discrimination and representativeness of the indices under different N application levels. Descriptive statistical, discrimitiveness and representativeness and factor analysis were used to select indices, in which the panicle number per plant and soil and plant analyzer development (SPAD) value were the key indices for evaluation and identification. Heatmap and hierarchical cluster analysis based on the average value of evaluation indices, and scatter plot based on the comprehensive value of N efficiency (P) according to formula showed that all varieties could be divided into five types under different N treatments. Our findings work toward developing N efficient rice varieties to improve NUE, reduce N fertilizer application and thus N waste, consequently mitigating the effects of rice production on the environment to ensure food security and sustainable agricultural development.

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The drastic reduction of agrobiodiversity has induced all countries in the world to implement numerous initiatives to safeguard genetic resources. The biodiversity issue is also one of the priority objectives of the global action plan for the conservation and sustainable use of FAO's cytogenetic resources and of the International Treaty on Plant Genetic Resources for Food and Agriculture. In Italy, the primary competence on genetic resources of agricultural interest is entrusted to the Ministry of Agricultural. In 2004, the Ministry entrusted the coordination of the RGV/FAO Project to CREA. The main objectives of the project, in addition to the inventory of accessions present in the collections of the structures involved, are their morphological, agronomic and molecular characterization and the productive enhancement with particular reference to the autochthonous varieties at risk of extinction. The project in question includes the activities of recovery and characterization of the viticultural germplasm illustrated in the present work. The 12 vines described here, like others yet to be rediscovered, are strongly linked to small winegrowers and indissolubly characterial of a territory in Campania Region that from the socio-cultural (rather fragmented agricultural system) and environmental orography point of view, like the national one, is very diversified.

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SUMMARYThe mountain ecosystem of the Central Himalayan Region is known for its diversity of crops and their wild relatives. In spite of adverse climatic conditions, this region is endowed with a rich diversity of millets. Hence, the aim of the present study was to explore, collect, conserve and evaluate the diversity of barnyard millet (Echinochloa frumentacea) to find out the extent of diversity available in different traits and the traits responsible for abiotic stress tolerance, and to identify trait-specific accessions for crop improvement and also for the cultivation of millets in the region as well as in other similar agro-ecological regions. A total of 178 accessions were collected and evaluated for a range of morpho-physiological and biochemical traits. Significant variability was noted in days to 50% flowering, days to 80% maturity, 1000 seed weight and yield potential of the germplasm. These traits are considered to be crucial for tailoring new varieties for different agro-climatic conditions. Variations in biochemical traits such as lipid peroxidation (0·552–7·421 nmol malondialdehyde formed/mg protein/h), total glutathione (105·270–423·630 mmol/g fresh weight) and total ascorbate (4·980–9·880 mmol/g fresh weight) content indicate the potential of collected germplasm for abiotic stress tolerance. Principal component analysis also indicated that yield, superoxide dismutase activity, plant height, days to 50% flowering, catalase activity and glutathione content are suitable traits for screening large populations of millet and selection of suitable germplasm for crop improvement and cultivation. Trait-specific accessions identified in the present study could be useful in crop improvement programmes, climate-resilient agriculture and improving food security in areas with limited resources.

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BACKGROUND: Blackcurrants are an important berry crop whose further development depends mainly on the diversity of available plant material and its successful inclusion in the breeding. OBJECTIVE: The study aimed to evaluate selected SSR markers’ applicability for the analysis of germplasm consisting of genotypes developed through complicated multistage crosses among different Ribes species and estimate the genetic structure and level of genetic diversity of the blackcurrant collection. METHODS: The set of 110 blackcurrant accessions from the Latvian genetic resources collection was genotyped using 18 previously described SSR markers. RESULTS: The marker set provided all genotypes with unique fingerprints and proved the need for reference genotypes in international studies for data validation. The accessions clustered according to pedigree and did not group by country of origin or breeding programme. CONCLUSIONS: The tested SSR markers uncovered relationships between blackcurrant accessions of complicated interspecific composition and revealed an extensive mutual exchange of germplasm among breeding programmes, thus pointing to the need for new donors of valuable characteristics. The results also highlighted the necessity to identify each species’ proportion in the hybrid material to assess the impact of species-linked gene expression.

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Olive (Olea europaea L.) is a species of great economic importance in the Mediterranean basin. Italy is very important for the olive industry; in fact, olive's genetic patrimony is very rich and characterized by an abundance of cultivars. At present, the majority of ancient landraces are vegetatively propagated by farm. It is likely that the number of cultivars is underestimated because of inadequate information on minor local cultivars that are widespread in different olive-growing areas. The existence of many cultivars reinforces the need for a reliable identification method. It is important to improve the ex situ plant germplasm collection and fairly to characterize all cultivars for future breeding programs. In the present report, we used 11 loci microsatellites to characterize 211 olive cultivars of an olive collection cultivated in six regions of southern Italy. These regions represent the major area for olive cultivation in Italy and have a strategic geographical location in the Mediterranean basin. The dendrogram obtained, using the unweighted pair group method with arithmetic mean clustering algorithm, depicts the pattern of relationships between the studied cultivars. There is a clear structuring of the variability relative to the geographic origin of olive cultivars. This work, for the very high number of the Italian olive cultivars analyzed, highlights the degree and distribution of genetic diversity of this species for better exploitation of olive resources and for the design of plant breeding programs. Besides, the use of molecular markers, like simple sequence repeats, is imperative to build a database for cultivar analysis, for traceability of processed food, and for appropriate management of olive germplasm collections.

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Eggplant is the fifth economically most important vegetable in the Solanaceae family after tomato, potato, chili, and tobacco. Apart from the well-cultivated brinjal or aubergine eggplant (Solanum melongena L.), two other underutilized eggplant species, the African eggplant (S. macrocarpon L.) and the scarlet eggplant (S. aethiopicum L.), were also cultivated with local importance where the leaves and fruits are used for food and medicinal purposes. The major objectives of the eggplant breeding program are to improve fruit quality, increase yield performance through heterosis breeding, and introduce pest and disease resistances from wild relatives. Europe and Asia hold a wide collection of germplasm resources with significant potential for genetic improvement. While cultivated eggplant is susceptible to several fungi and bacteria, many wild relatives offer potential resistance to these pathogens. In this paper, we review the genetic resources and diversity of cultivated eggplant and its wild relatives. As a point of departure, we examine the economic importance, domestication, taxonomy characterization, and relationships of the crop and its wild relatives. The importance of evaluating and safeguarding wild relatives is highlighted, as crop wild relatives are highly underrepresented. A key section in this study is an overview dedicated to genetic resources, resistance to biotic and abiotic stresses, pre-breeding, and breeding for sustainable eggplant production.

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The USDA-ARS National Plant Germplasm System Malus collection is maintained by the Plant Genetic Resources Unit (PGRU) in Geneva, NY. In the 1990s, a core subset of 258 trees was hand-selected to be representative of the grafted Malus collection. We used a combination of genotypic and phenotypic data to compare the diversity of the 198 diploid trees in the original core subset with that of 2114 diploid trees in the grafted field collection for which data were available. The 198 trees capture 192 of the 232 total microsatellite alleles and have 78 of the 95 phenotypic characters. An addition of 67 specific individuals increases the coverage to 100% of the allelic and phenotypic character states. Several de novo core sets that capture all the allelic and phenotypic character states in 100 individuals are also provided. Use of these proposed sets of individuals will help ensure that a broad range of Malus diversity is included in evaluations that use the core subset of grafted trees in the PGRU collection.

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Pea is an important grain legume and vegetable in the South of Europe where it is grown on small farms and gardens using traditional varieties and methods during the winter. Variability in old, unimproved varieties needs to be determined in order to create useful genetic variation for broadening the narrow genetic base of commercial cultivars and for making efficient use of available resources. One hundred and four unimproved pea varieties and ten elite cultivars were evaluated in 1991 and 1992 at two locations for seed and vegetable quality, canopy and agronomic traits. Significant genotype by environment (G × E) interactions were found for protein concentration, fresh seed size and weight, canopy traits, pod length and weight, days to flowering, and days to fresh seed and pod maturity. There were significant differences between unimproved pea varieties for all traits studied except for seed soluble sugars and seed tenderness. Most of the significant differences for seed and vegetable quality traits were observed in the unimproved germplasm from the South of Europe when compared with differences within the elite germplasm. Data from the evaluation of available pea germplasm provide information needed by breeders to develop varieties efficiently for the different needs of growers, processors and feed manufacturers. The relevance of these results in devising breeding strategies is discussed. Key words: Pisum sativum, seed and vegetable quality, field performance, genotype by environment interaction

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AbstractWild soybean (Glycine soja) is a valuable genetic resource for soybean improvement. Seed composition profiles provide beneficial information for the effective conservation and utilization of wild soybeans. Therefore, this study aimed to assess the variation in free amino acid abundance in the seeds of wild soybean germplasm collected in Japan. The free amino acid content in the seeds from 316 accessions of wild soybean ranged from 0.965 to 5.987 mg/g seed dry weight (DW), representing a 6.2-fold difference. Three amino acids had the highest coefficient of variation (CV): asparagine (1.15), histidine (0.95) and glutamine (0.94). Arginine (0.775 mg/g DW) was the predominant amino acid in wild soybean seeds, whereas the least abundant seed amino acid was glutamine (0.008 mg/g DW). A correlation network revealed significant positive relationships among most amino acids. Wild soybean seeds from different regions of origin had significantly different levels of several amino acids. In addition, a significant correlation between latitude and longitude of the collection sites and the total free amino acid content of seeds was observed. Our study reports diverse phenotypic data on the free amino acid content in seeds of wild soybean resources collected from throughout Japan. This information will be useful in conservation programmes for Japanese wild soybean and for the selection of accessions with favourable characteristics in future legume crop improvement efforts.

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N.I. Vavilov, Academician of the V.I. Lenin All-Union Academy of Agricultural Sciences, takes his place as a founding pillar of knowledge in the cathedral of the origin and development of cultivated plants. Relying on the theories of his revered predecessors, Charles Darwin and Alphonse de Candolle, Vavilov developed the concept of centers of origin for agronomic crops. Vavilov’s astute hypotheses set the stage for the modern use of exotic germplasm in plant breeding. Vavilov, a devoted scientist, continued to revise and refine his theory of the centers of origin throughout his lifetime based on additional plant collections and data evaluation. Though he initially proposed three in 1924, and eight in 1935, his final papers of 1940, discussed seven major centers with some minor additions. His concept of specific centers of origin for crop plants was not an isolated aphorism but has directed breeders, on their study and reflection, to the continued improvement and economic development of plants for humanity. Inherent genetic plant variability is the basis of domestication and breeding into crops of economic importance with food, fuel, fiber, and industrial uses. The objective of this article is to present a summary of Vavilov’s plant explorations. His collection trips led to the development of his theory of the centers of origin of cultivated crops, the law of hom*ologous variation, as well as his concept of genetic erosion. Further modification of his theories by other scientists and the impact of his ideas are mentioned. His influence on present day conservation of genetic resources are presented.

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Abstract An extensive working collection of Arachis germplasm is maintained by the USDA at the Southern Regional Plant Introduction Sta. in Griffin, GA. Much of this collection is maintained also under long-term seed storage at the Nat. Seed Storage Lab. in Ft. Collins, CO. The working collection consists of 9027 accessions of A. hypogaea and 684 accessions of Arachis species. About half of the A. hypogaea accessions are unimproved landraces collected in the crop's centers of diversity in South America. The other half is comprised of germplasm obtained from countries outside of South America. The U.S. germplasm collection of peanut was the first major germplasm collection to have a working core collection. Research has verified that this core collection can be used to improve the efficiency of germplasm utilization. This has stimulated a great amount of germplasm evaluation work and has resulted in the identification of numerous sources of resistance to several economically significant pathogens. Considerable efforts in the U.S. also have been devoted to the use of wild species of Arachis for sources of resistance to pathogens. Programs are ongoing to introgress high levels of resistance or immunity to early (Cercospora arachidicola Hori) and late (Cercosporidium personatum Berk. & M.A. Curtis) leaf spots, nematodes, and viruses. Genetic resources have been particularly useful in adding disease resistance to peanut cultivars. This has had a significant economic impact on U.S. peanut farmers. The largest impacts have been from the development of cultivars with resistance to Sclerotinia blight (Sclerotinia minor Jagger), the peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1], and tomato spotted wilt Tospovirus. Use of these resistant cultivars has an estimated economic impact of more that $200 million annually for U.S. peanut producers.