Characterization of a landrace collection for Tomàtiga de Ramellet (Solanum lycopersicum L.) from the Balearic Islands

Tomàtiga de Ramellet (Ramellet) is a traditional long-storage tomato from the Mediterranean Islands of Mallorca, Menorca, Eivissa (Ibiza), and Formentera (Balearic Islands). To investigate the observed phenotypic and shelf life variability within local varieties, we studied 142 accessions characterized as Ramellet varieties, and 29 accessions representing other local varieties. The 171 accessions constitute a new germplasm collection at the University of Balearic Islands (UIB). The evaluation of the collection demonstrated wide variability in most agronomic, morphological and quality traits of Ramellet accessions and clearly differentiates them from other local varieties with respect to fruit shape, size, fruit composition, and fruit storage. All accessions of Ramellet evaluated have the ripening mutation alcobaça (alc), suggesting an important role for this variant in controlling shelf life. Results of evaluation also showed wide variability between the Ramellet accessions for storage time, suggesting that other traits like fruit size and composition may play a role in fruit conservation. Observed variation within the Ramellet accessions is consistent with a genetically variable population or landrace group. The establishment of this collection will help prevent genetic erosion of this local landrace group and constitute a resource for future investigation and breeding.     

Characterisation and Variation of Morphological Traits and Storage Proteins in Spanish Emmer Wheat Germplasm (<Emphasis Type="Italic">Triticum Dicoccon</Emphasis>)

Emmer wheat is hulled wheat that was wide cultivated in Spain at the past. Actually, the most of this germplasm is conserved in Germplasm Banks, and only two small populations have been found in Asturias (North of Spain) in a recent collecting mission. In this work, a collection of 31 Spanish emmer lines developed from identical number of accessions of two Germplasm Banks was analysed for morphological spike traits and seed storage protein composition. Up to seven different botanical varieties were detected, which suggest the presence of a wide diversity, although lower than the historically described 10 botanical varieties. At level of seed storage proteins, the lines showed a high diversity, although the new alleles were present with low frequency in materials with scarce agronomic interest for the farmers (var. atratum, var. lagascae or var. pycnurum). This last circumstance could translate in a lost of variability by genetic drift.     

Biodiversity in the barnyard millet (<Emphasis Type="Italic">Echinochloa frumentacea</Emphasis> Link,Poaceae) germplasm in India

One hundred ninety four accessions of barnyard millet collected from different eco-geographical regions of India were evaluated for 14 quantitative traits during kharif 2003 and 2005. These accessions were grouped into 5 groups on the basis of place of collection. These groups differed significantly in their mean values for quantitative traits and magnitude of correlation among traits indicates origin based association. The group ‘C’ (source of origin is unknown) was found most diverse group (mean coefficient of variation 17.67%), while rest of the groups recorded mean coefficient of variation between 12 and 13%. Correlation studies indicate that flag leaf width, number of racemes along with internode length should be considered while performing selection in segregating generations. The plotting of first and second principal component axes scores suggests that presence of three distinct morphotypes in the present study. These morphotypes are quite similar to three botanical varieties viz., var. robusta, var. intermedia and var. stolonifera in their morphological traits, while botanical variety laxa (endemic to Sikkim area of India) was completely absent from the present study.     

Wild melon diversity in India (Punjab State)

We present here the first comprehensive genetic characterization of wild melon accessions from northern India. The genetic diversity among 43 wild melon accessions collected from the six agro-ecological regions of the Punjab State of India was assessed by measuring variation at 16 Simple Sequence Repeat (SSR) loci, morphological traits of plant habit and fruit morphological traits, two yield-associated traits, root nematode resistance and biochemical composition (ascorbic acid, carotenoids, titrable acidity). Variation among accessions was observed in plant habit and fruit traits and wild melon germplasm with high acidity and elevated carotenoid content and possessing resistance to Meloidogyne incognita was identified in the collection. A high level of genetic variability in wild melon germplasm was suggested by SSR analysis. Comparative analysis using SSRs of the genetic variability between wild melons from the north and other melons from the south and east regions of India and also reference accessions of cultivated melon from Spain, Japan, Korea, Maldives, Iraq and Israel, showed regional differentiation among Indian melon accessions and that Indian germplasm was not closely related to melon accessions from other parts of the world. A highly drought tolerant accession belonging to var. agrestis Naud. was also identified.     

A wide range of genetic diversity in pear (<Emphasis Type="Italic">Pyrus ussuriensis</Emphasis> var. <Emphasis Type="Italic">aromatica</Emphasis>) genetic resources from Iwate,Japan revealed by SSR and chloroplast DNA markers

Iwateyamanashi (Pyrus ussuriensis var. aromatica) is one of the Pyrus species which grows wild in Japan. The number of Iwateyamanashi trees has been decreasing, so conservation and evaluation is urgently needed. Over 500 accessions of Pyrus species collected from Iwate in northern Tohoku region are maintained at Kobe University as an Iwateyamanashi germplasm collection. In order to investigate the genetic diversity, five SSR (simple sequence repeat) markers, developed from Japanese and European pear were examined for 86 Pyrus individuals including 58 accessions from Iwate. These SSR loci could discriminate between all the Iwate accessions except for 10 that bear seedless fruit, as well as determine the genetic diversity in Iwateyamanashi germplasms. High levels of variation were detected in 41 alleles and the mean observed heterozygosity across 5 loci was 0.50 for the Iwate accessions. Seedless accessions sharing identical SSR genotype with the local pear variety “Iwatetanenashi” were supposed to have been propagated vegetatively via grafting. In an UPGMA phenogram, Japanese pear varieties (P. pyrifolia) were clustered into two groups with some Iwate accessions including seedless ones. Another 38 Iwate accessions were not clustered clearly, and there was no clear relationship between these accessions and geographical distribution or morphological characters. Allele frequency revealed that the Iwate accessions were genetically more divergent than the Japanese pear varieties. Most Japanese pears possessed a 219 bp deletion at a spacer region between the accD and psaI genes in the chloroplast DNA (cpDNA), but other Pyrus species and two Iwateyamanashi trees did not. In the Iwate accessions, 79.3% had a deletion type cpDNA and others had a standard type cpDNA without deletion. These results are indicative of the wide range of genetic diversity in the Iwate accessions which include Japanese pear varieties. A combination of SSR and cpDNA analyses revealed high heterogeneity in Iwateyamanashi and coexistence of Iwateyamanashi and hybrid progeny with P. pyrifolia. These could be reasons for the wide range of continuous morphological variation described previously.     

Pheno-morphological,agronomic and genetic diversity among natural populations of sulla (<Emphasis Type="Italic">Hedysarum coronarium</Emphasis> L.) collected in Sicily,Italy

Sulla (Hedysarum coronarium L.) is a short-lived perennial forage legume that plays a key role in cereal-based systems in semi-arid Mediterranean regions, particularly in organic production and low-input oriented agriculture. In Sicily, the species is widespread both as a wild and cultivated plant. The present study assessed the phenotypic and genetic variation among natural populations of sulla collected from different environments throughout Sicily and analysed how the patterns of phenotypic diversity varied according to the environmental parameters of each collection site. Two commercial varieties and two Sicilian agro-ecotypes were also included in the study as controls. Principal components analysis (PCA) was performed on the sites using geographic, climatic, and pedological data to assess the differences in types of collection sites. PCA was also performed on the accessions (using pheno-morphological and agronomic data) to establish the importance of different traits in explaining multivariate polymorphisms. The results showed a large degree of genetic diversity (based on ISSR markers) and variability in pheno-morphological and agronomic traits. PCA did not clearly differentiate the accessions according to their habitats of origin, but in some cases accessions from the same habitat had a tendency to group together. The agronomic attributes of several populations were more pronounced than those of the controls. The observed variability may be valuable when selecting for H. coronarium varieties suitable for various uses (e.g., hay production, grazing, soil protection).     

Phenotypic biodiversity of an endemic wild pear, Pyrus mamorensis Trab., in North-Western Morocco using morphological descriptors

In this paper, we report on morphological diversity, ecology and flowering phenological records of an endangered and an endemic species of Morocco Pyrus mamorensis Trab. For this study, a survey was undertaken in North-Western Morocco (Mamora forest and Zaër region) whereby 67 accessions of P. mamorensis were sampled. A set of 33 genotypes of Pyrus spp. from the international collection INRA-Angers (France) of the genus Pyrus were also analyzed. The variability of the total of 100 accessions was assessed by twenty-six characters including fourteen qualitative and twelve quantitative traits. The results demonstrated high levels of morphological variation in the sampled accessions of P. mamorensis and established the relationships among the local germplasm using the UPGMA cluster analysis and the factorial discriminant analysis. Furthermore, we were able to distinguish three types of flowering in the Mamora forest: early, intermediate and late flowering type. Otherwise, the UPGMA classification comparing local accessions of P. mamorensis to the international collection led to the formation of four major groups showing the closest correspondence to their geographical origins: (1) The North African species represented by P. mamorensis, (2) The East Asian pea species, (3) The West Asian species and (4) The European species. These findings suggest the importance of implementing a conservation strategy preserving the genetic resources of wild pear in North-Western Morocco.     

Genetic diversity of the complex Paspalum notatum Flügge (Paniceae: Panicoideae)

The genus Paspalum L. comprises approximately 400 species worldwide and about 220 in Brazil. Paspalum is ecologically and economically important, and has been very useful as pasture and P. notatum Flügge (bahiagrass) is a valuable forage grass in the subtropics. This species consists of several sexual (diploid) and apomictic (tetraploid, ocasionally tri and pentaploids) biotypes. In this work, inter simple sequence repeats (ISSR) markers were used to assess the genetic variability of a bahiagrass (P. notatum) collection. Vegetative tissues of 95 bahiagrass accessions were obtained from various locations in South America (Brazil, Argentina and Uruguay). A total of 91 reproducible ISSR fragments were observed and 89 fragments (97.5% of the total observed) were polymorphic. Cluster analyses (UPGMA) were performed from the ISSR data set and the results illustrate the genetic relationships among the 95 accessions of P. notatum. A comparison among molecular, morphological and ploidy levels data were done. ISSR markers were effective in distinguishing the genotypes analyzed, and a wide variability was observed for this species. These results add new information regarding the genetic diversity in P. notatum, thus contributing toward the biological knowledge of this species, and providing with subsides for future plant breeding and conservation programs.     

<Emphasis Type="Italic">Macrotyloma axillare</Emphasis> and <Emphasis Type="Italic">M. uniflorum</Emphasis>: descriptor analysis,anthocyanin indexes,and potential uses

The purpose of this study was to characterize and identify potential new uses for perennial horsegram (Macrotyloma axillare) and horsegram (M. uniflorum) germplasm in the USDA, ARS collection. Seven morphological and yield parameters were studied in 11 M. axillare and 32 M. uniflorum accessions. A wide variation was found in stem branching, foliage, plant height, seed number, and seed weight. Leaf anthocyanin indexes were significantly higher than control flowers from PI 345729. Phytochemical traits exist in both species for potential use as nutraceuticals, forage, and food for humans.     

Diversity among landraces of Indian snapmelon (<Emphasis Type="Italic">Cucumis melo</Emphasis> var. <Emphasis Type="Italic">momordica</Emphasis>)

Diversity among 36 snapmelon landraces, collected from 2 agro-ecological regions of India (9 agro-climatic sub-regions), was assayed using RAPD primers, morphological traits of plant habit and fruit, 2 yield-associated traits, pest and disease resistance and biochemical composition (TSS, ascorbic acid, titrable acidity). Typical differences among accessions were observed in plant and fruit characteristics and snapmelon germplasm with high titrable acidity and possessing resistance to downy mildew, Cucumber mosaic virus, Zucchini yellow mosaic virus, Papaya ringspot virus, Aphis gossypii and Meloidogyne incognita was noticed in the collection. RAPD based grouping analysis revealed that Indian snapmelon was rich in genetic variation and region and sub-region approach should be followed across India for acquisition of additional melon landraces. Accessions of var. agrestis and var. momordica clustered together and there was a separate cluster of the accessions of var. reticulatus. Comparative analysis of the genetic variability among Indian snapmelons and an array of previously characterized reference accessions of melon from Spain, Israel, Korea, Japan, Maldives, Iraq, Pakistan and India using SSRs showed that Indian snapmelon germplasm contained a high degree of unique genetic variability which was needed to be preserved to broaden the genetic base of melon germplasm available with the scientific community. N. P. S. Dhillon and Ranjana contributed equally to this work and are considered the first authors.     

Genetic diversity among Polish landraces of common oat (Avena sativa L.)

All over the world about 220,000 accessions of the genus Avena is preserved in gene banks. Polish oats collection, in the National Centre for Plant Genetic Resources, consists of about 2,500 accessions. More than 80 % of them belong to the species Avena sativa. Only 136 accessions have the landrace or traditional cultivar status and 91 of them were collected in Poland. The main objective of this study was to estimate genetic diversity of a set of 67 Polish landraces using inter simple sequence repeat (ISSR) markers. We also tried to determine whether genetic diversity depended on the region and altitude of collection site and if there was a relationship between DNA polymorphism and some morphological traits. The accessions were collected between years 1973 and 1999 from areas of Northern, Southern and Eastern Poland. The obtained results indicated a relatively low diversity (0.09–0.37) of the common oat landraces. Analysis of molecular variation (AMOVA) showed that there were no significant differences within designated geographic regions. It indicated that at the same time the altitude of collection site had significant effect on the genetic differentiation of the accessions. AMOVA also showed the presence of variance between groups formed on the basis of the colour of lemma. White lemma accessions were also characterized by highest genetic distinctiveness. Considering the evident impact of local climatic conditions on the genetic distinctiveness of Polish landraces utility of them in the Polish breeding programs should be considered.     

A new collection of wild populations of Capsicum in Mexico and the southern United States

An exploration and collection mission for wild populations of Capsicum was carried out in the fall of 2006 and 2007, in 13 Mexican states and in the U.S. states of Arizona and Texas. The aim of this collection was to expand the number of accessions of wild chile pepper (Capsicum annuum var. glabriusculum and Capsicum frutescens) that are publicly available for research in plant improvement and for subsequent use in an inquiry into the domestication of C. annuum. While Mexico and the United States National Plant Germplasm System both have germplasm repositories INIFAP—Instituto Nacional de Investigaciones Forestales—Agrícolas y Pecuarias and USDA GRIN—United States Department of Agriculture’s Genetic Resources Information Network) with accessions of C. annuum var. glabriusculum, the very limited number available, their age, and/or validity of the information attached to many accessions do not allow for extensive research. Four hundred and sixty-six plants were sampled over two field seasons, of which copies of the collection reside in both UAA and at UC Davis. Given the current environment with the intellectual property of varieties of crop plants and, particularly, the extreme restrictions affecting explorations and the official procuring and sharing of germplasm across national borders, this U.S.—Mexico collaboration is one of the few examples of joint U.S.—Mexico germplasm collection efforts.     

The Sierra Norte of Madrid: an agrobiodiversity refuge for common bean landraces

At the mountain area close to the city of Madrid, common beans were one of the main food crops present in everyday diet until 1960. This paper describes the morphological diversity, for forty-six phenological and morphological traits, found in forty-three traditional varieties of common beans collected in this area and seven commercial varieties used as reference. That comparison suggests that common bean breeding programs have led to later varieties with a higher production of straight pods. Quantitative traits showed also similar values when compared to the Iberian common bean collection, except for the phenological and seed size characters. The phenological differences could suggest an ecological adaptation of the studied landraces to the regional environmental conditions. The different seed size averages of both collections might correspond to the scarce presence of smaller seed-type common beans in Madrid collection. All the accessions collected in the Sierra Norte of Madrid belong to any of the groups included in the Spanish core collection. Madrilenian collection is also composed by indeterminate growth habit varieties, while the presence of bush accessions is relatively uncommon. Most of the Madrilenian landraces have a remarkable fitness for green-pod consumption (42 %) and their seeds are mainly white (30 %), ovate-shape (49 %) and medium-large (40 %). The study of seed storage protein allowed to classify the landraces according to their domesticated gene pools. Most of them (72 %), with T and C phaseolin type, seem to belong to Andean germplasm, while the remaining (28 %), with S and B phaseolin type, to Mesoamerican one. The remarkable morphological diversity of common beans found in this small area is a symptom of a broad genetic base despite genetic erosion, what indicates a widespread crop in the past. Therefore, it is advisable to design agro-environmental policies to promote the production and commercialization of common bean landraces in Sierra Norte of Madrid.     

Genetic diversity and phenotypic variation for drought resistance in alfalfa (<Emphasis Type="Italic">Medicago sativa</Emphasis> L.) germplasm collected for drought tolerance

Drought is a major environmental factor hampering alfalfa productivity worldwide. Gene banks provide an array of trait diversity, frequently consisting of specific seed collection projects that focused on acquiring germplasm adapted to specific traits such as drought tolerance. These subsets provide a logical starting point to identify useful breeding resources. In the present study, we investigated the genetic diversity and evaluated 18 agronomic, physiological and quality traits associated with drought tolerance in a subset of 198 alfalfa accessions collected for their potential drought resistance. Significant differences were found among accessions for most of the traits evaluated. Water deficit significantly decreased biomass dry yield by 61.9% compared with well-watered control. A positive correlation was found between relative water content (RWC) and drought susceptible index, while negative correlations were found between RWC and leaf senescence (LS), and between RWC and canopy temperature (CT). Alfalfa accessions with high RWC showed relative lower yield reduction, cooler CT and delayed LS. Genetic variation for forage quality was also investigated and the correlation between agronomic and quality traits was analyzed. Biomass yield under drought was negatively correlated with total protein, relative feed value and relative forage quality, suggesting that the efforts to improve yield under drought tend to negatively affect forage quality. Therefore, maintaining forage quality should be considered for breeding alfalfa with drought resistance. Alfalfa accessions with high drought resistance scores and minimum loss of quality were identified in this study and can be used as genetic resources for developing alfalfa varieties with improved drought resistance and water use efficiency while maintaining forage quality.     

Morphological patterns in a world collection of <Emphasis Type="Italic">Cleome gynandra</Emphasis>

Cleome gynandra L. is a leafy vegetable native to sub-Saharan Africa and Asia and cultivated on dry areas. The plant plays an important role in the food and nutrition security of local communities. The objective of this study was to illustrate variation and diversity in the Cleome collection held at the World Vegetable Center. In total, 242 accessions were cultivated and morphologically characterized and analyzed. The gynophore and filament, both important organs of the flower, played a key role in taxonomical identification. High morphological variation was detected in traits including plant height, pod length, leaf size, flower color, and earliness. Distinct morphological differentiation was detected between Asian and African accessions. On average, the African accessions were larger, less uniform and later in flowering and seed maturation than the Asian accessions. The results were used to establish a core collection of 49 Cleome accessions. Gaps in the current collection were detected. High within-accessions diversity challenges the existing ex situ conservation system; to maintain diversity, seed should be collected from a large number of plants, both during the collection mission and in ex situ regeneration. The results are relevant for germplasm collection strategies and regeneration protocols for good genebank practices.     

Water yam (Dioscorea alata L.) diversity pattern in Brazil: an analysis with SSR and morphological markers

Substantial progress was made in the last decade in understanding the diversity in Dioscorea species. However, most of the studies so far concentrated in the ‘yam belt in Africa’. We present a genetic diversity and structure analysis among commercial and local varieties of water yam (Dioscorea alata L.) in Brazil using microsatellite and morphological markers. Twelve microsatellite primers were used to generate DNA profiles of 72 local varieties and 17 commercial accessions of water yam collected in four different regions in Brazil. Also, four morphological traits were evaluated on individual plants under field conditions. The morphological characterization showed considerable diversity. High polymorphism was found with 100 % polymorphism observed for 11 primers and a discriminating power value of 0.92, on average. We did not observe a strong population structure among sampling regions, while most of the genetic diversity was concentrated within regions (95.9 %). Analysis of the relationship between accessions did not clearly separate the local and commercial genotypes. However, the molecular analyses of D. alata showed high intraspecific diversity in local accessions from different regions in Brazil, with the highest Shannon index value (H′ = 0.41) for the Southeast region. These results confirmed an admixture of accessions in all sampling regions, consistent with the lack of a significant correlation between geographic and genetic distances, suggesting that farmers exchanged water yam materials extensively. The genetic diversity can be explained by the result of a continuous exchange of accessions by farmers throughout Brazil.