Mungbean (Vigna radiata (L.) Wilczek), also known as greengram, is the most widely cultivated Asian Vigna species. Improved mungbean cultivars have a narrow genetic base that limits yield potential and they are poorly adapted to varying growth conditions in different agro-ecological conditions. The genetic potential of landrace germplasm accessions in gene- banks therefore needs to be better exploited. Germplasm core collections are made of a reduced set of representative accessions from the entire diversity maintained by genebanks. This subset of accessions can be used for testing general combining ability with local germplasm in the search for yield enhancement. Core collections also help breeders in selecting parental material that could maximize potential genetic gain from derived hybrid populations. At the National Bureau of Plant Genetic Resources (NBPGR), India, genetic enhancement/pre- breeding studies in mungbean have been initiated involving diverse parents mainly from the cultivated gene pool, using the Bureau's core collection as starting material. Germplasm enhancement aims at widening the genetic base of breeding materials by transferring desired genes from unimproved germplasm into enhanced varieties. Mild and decentralized selected material was maintained in target sites across the country. A total of 102 progenies were advanced to F5 for further selection and use by the breeders in Delhi. The genetic potential of a few selected enhanced progenies with desired plant types and better yield-related traits is presented in this paper. The study clearly demonstrates the potential of germplasm accessions conserved in genebanks for use in large-scale base-broadening efforts in mungbean.

The use of plant genetic resources (PGR) in crop improvement, followed by adoption, cultivation and consumption or marketing of the improved cultivars by farmers, is one of the most sustainable methods to conserve valuable genetic resources for the future, and simultaneously to increase agricultural production and food security. The objective of this review is to summarize issues related to the use of PGR in crop improvement. Specific topics are: definition of genetic resources for crop improvement; information sources on the internet; documentation and evaluation of PGR; access to PGR, equitable sharing of profits, and material transfer agreements; impediments to the use of PGR in crop improvement; classical methods of using PGR in crop improvement (introgression, incorporation, prebreeding and wide crosses); use of landraces in breeding for specific adaptation to stress environments; utility of molecular markers and genomic research for using PGR in crop improvement (diversity assessment, mapping of quantitative trait loci (QTL) and marker-assisted selection (MAS), advanced backcross QTL analysis and introgression libraries, association studies and direct allele selection); and gene transfer. Practical examples or experimental results are given for most aspects.

Sesame (Sesamum indicum L.) is one of the world's oldest oil crops and has been cultivated in Asia from ancient times. India has a rich diversity of this crop and a landrace collection is maintained at the National Genebank at the National Bureau of Plant Genetic Resources (NBPGR). The breeding potential of this germplasm has been hardly exploited to date. The major hindrance for the utilization of these resources is the transfer of diversity into a form that can be easily used by breeders and farmers. As part of a core collection strategy, a selection was made of 24 of the most diverse and unadapted parental lines, including one accession of the wild species S. mulayanum, and these were intercrossed in various combinations to maximize genetic diversity and to develop locally adapted pools of genetic resources. A weak and decentralized selection regime was maintained at four selected target sites on the progeny of 103 crosses. The range of variation in the selected F4 progenies was assessed, and promising types with desired plant characteristics and high seed yield were selected. Realized genetic gains, especially for yield-related traits, were also assessed. Only a limited fraction of the existing diversity held in the genebank was used in the present study and there is much more diversity available for large-scale genetic enhancement of sesame in the future.

Diversity in agronomically important traits of wild emmer wheat, Triticum dicoccoides, the progenitor of most cultivated wheats, was examined in l60 genotypes representing 16 populations derived from a wide ecogeographical spectrum of climate, soil and water availability in Israel and Turkey. The analysis included 14 quantitative economic characters including heading date, culm length, biomass, grain yield and its components, and grain protein percentage.

The results led to two major conclusions: (i) agronomically important traits varied genetically: ecogeographic diversity in these traits is dramatically displayed when populations are grown in a relatively standardized environment; and (ii) genetic diversity is revealed not only between, but also within populations. Thus, genotypes excelling in some of these characters were found in several populations.

Southern Sudan has a low population density, abundant land and tremendous agricultural potential. A large number of domesticated crops are grown in the region in a range of cropping systems. There are also numerous useful wild plant genetic resources. Little collecting work has been done in the region, there are few accessions from southern Sudan stored ex situ and publications on the actual and potential plant genetic resources for agriculture are sparse. The region has been a centre of civil conflict with little respite since independence in 1956. The farmers’ fields and natural environments represent in situ genebanks, which following the cessation of hostilities will become extremely important for the rehabilitation of subsistence agriculture, the promotion of cash crop production and the revitalization of the regional economy. Several wild plant species are highly nutritious and merit the attention of plant scientists. This article describes some of the domesticated, semi-domesticated and wild plant genetic resources of the area, and suggests why these are important for agricultural rehabilitation following implementation of a peace accord.

Pepper (Capsicum sp.) is important in human diets in many parts of the world and a major source of several antioxidants, including carotenoids, ascorbic acid, tocopherols and phenolics. More information on genetic diversity within Capsicum for antioxidant (AO) content and antioxidant activity (AOA) could contribute to improved human health. We evaluated 46 Capsicum accessions from AVRDC—the World Vegetable Center Capsicum core collection for content of nine AO (five carotenoids, ascorbic acid, tocopherols α and γ, and total phenolics) and two AOA assays for 2 years in south Taiwan. Ample genetic diversity exists within C. annuum to increase AO content. Based on dry weight values, non-pungent C. annuum entries as a group were significantly greater than pungent entries for contents of β-cryptoxanthin (36%), ascorbic acid (65%), total phenolics (36%) and α-tocopherol (11%). Group means of the brown-fruited entries exceeded the means of red-fruited entries for capsanthin (34%), zeaxanthin (37%), lutein (36%), β-cryptoxanthin (71%), β-carotene (82%), ascorbic acid (19%) and α-tocopherol (40%). Red-fruited C. annuum entries ‘Verdano Poblano’ and ‘Guajillo Ancho’ from Mexico ranked among the entries highest for all carotenoids, ascorbic acid and α-tocopherol. The inhibition of lipid peroxidation (ILP) assay could be adopted for AOA characterization or selection because of high variation among entries and consistent entry performance over years. ILP was positively correlated with phenolics (r=0.72**) and ascorbic acid (r=0.58**) contents. Significant positive correlations were detected between most carotenoids as well as a significant positive correlation between ascorbic acid and total phenolics contents (r=0.78**).

A natural population of Vriesea friburgensis var. paludosa was genetically and demographically characterized. Four selected enzymatic systems were used. In total, 10 allozymic loci were analysed. The proportion of polymorphic loci was 70% and the number of alleles per locus was 2.3· The mean observed and expected heterozygosities were 0.234 and 0.226, respectively. An excess of heterozygotes was revealed by the value of the fixation index (—0.035). These indices showed the presence of high levels of genetic diversity in the population studied. A demographic survey revealed almost six times more vegetative than sexually reproductive plants. Reproductive plants were found only in clusters. The genetic diversity exhibited by this population, associated with vegetative as well as sexual propagation, resulting in clusters or colonies, would allow the employment of a sustainable management strategy for species conservation as well as its exploitation as an ornamental.

The concept of agro-sustainability is presented and discussed. The paper shows that sustainable farming practices, sustainable development and the preservation of biological diversity require adequate valorization of local biodiversity. Special emphasis is given to neglected and underutilized crop species. The role and importance of these plants, including primitive wheat, wild anise, food legumes, several vegetables and forage legumes in southern Italy is presented. Each case is presented as an example of cultivation linked to different aspects of utilization, conservation, genetic erosion, and of their potential for sustainable agriculture.

Vavilov (1935) described China as the earliest and largest independent centre of origin of cultivated plants. Gansu Province occupies the geographic centre of China. With an area of 454,000 km2, latitudes ranging from 32°3′N to 42°57′N and elevations varying from 500 to 6200 m, the province has an extremely diverse climate and topography. Stretching 1653 km along the ancient Silk Road, Gansu also has a long history of agriculture (6000 years) and for centuries was exposed to dynamic cultural exchanges between the East and the West. The unique combination of these conditions allowed rapeseed to be introduced from Europe and the Middle East, to evolve over a long time of cultivation and to diversify to adapt to many types of ecological conditions and cropping systems in Gansu. Currently, rich genetic resources exist in Gansu for Brassica rapa, B. juncea, B. chinensis and Eruca sativa. Eight landraces are described to demonstrate the diversity of rapeseed genetic resources in Gansu. It is generally recognized that B. chinensis originated in China. Information provided in this paper suggests that Gansu and its adjacent regions could also be a centre of diversity for B. rapa and B. juncea.

Wild relatives of crop species are known to be sources of genetic diversity that can be used in crop improvement. However, they have not always been studied adequately for the variation that may exist within them, for traits which may have important implications from an evolutionary point of view and their use in breeding programmes. In the present study, a wild groundnut species, Arachis stenosperma, has been studied for variation between accessions collected from different sites in Brazil for morphological and certain nutritional traits, and for disease resistance. Multivariate analysis of 23 characters grouped 18 accessions into two clusters, while one accession, ICG 14927, was distinct from these. However, in protein profile they all appear identical. Hence, the variation appears to have arisen in response to the climatic conditions of their habitat, which has implications for use of these accessions in breeding programmes. The variation in these traits could not be associated with any phytogeographical regions. The dispersal of this species from its centre of origin and diversity to other parts of Brazil appears to be recent and without any identifiable selection pressures having operated.

In a search for high-quality jute (Corchorus olitorius) fibre using phenotypic marker(s), a single plant from CRIJAF accession OIJ 154 was isolated on the basis of its unique red-tinted pale green stem, which becomes crimson red at maturity, and was given a code name, PPO4. Progenies from this selection bred true with respect to morphological characters. It has a slightly lower height at maturity, but has comparable yield and a higher harvest index when compared to the most popular high-yielding variety JRO 524. In spite of having lower chlorophyll per unit weight of leaf tissue, the photosynthetic rate per unit chlorophyll, the relative growth rate of PPO4 was higher than JRO 524. A composite analysis of quality parameters indicated that the genotype is of higher grade (between TD2 and TD3) with very fine (1.5 tex) fibre of high tensile strength (19.7 g/tex). The lignin content (ca 14%) of the fibre was also less than that of JRO524 (ca 17%) under standard assay conditions. This plant type, with distinct morphological markers, could be utilized in breeding programmes for the genetic improvement of jute.

The technique of inter-simple sequence repeat-polymerase chain reaction (ISSR-PCR) was used to fingerprint blackgram (Vigna mungo) genotypes in order to differentiate them at a molecular level. Twenty-four primers were used to analyse 11 blackgram genotypes. The genotypes used in the study could be differentiated based on combined amplification profiles generated by two primers (UBC primer numbers 808 (AG)8C and 826 (AC)8C). It was observed that 3′-anchored repeat primers based on (AG) and (GA) repeats amplified a greater number of bands than 3′-anchored repeat primers of (CA) and (AC) repeats. This result perhaps indicates that GA/AG repeats are more frequent than CA/AC repeats in the blackgram genome.

A set of 68 simple sequence repeat (SSR) markers were selected from existing databases (including Medicago, soybean, cowpea and peanut) for the purpose of exploiting the transferability of SSRs across species and/or genera within the legume family. Primers were tested for cross-species and cross-genus fragment amplification with an array of 24 different legume accessions. Nearly one-third (30.78%) of the SSR primers screened generated reproducible and cross-genus amplicons. One hundred and seventeen cross-species polymorphic amplicons were identified and could be used as DNA markers. These polymorphic markers are now being used for characterization and evaluation of our collected and donated legume germ- plasm. The transferability of SSRs, mis-/multiple-primings, homologous/heterologous amplifications, single/multiple-amplicons and application of these amplicons as DNA markers are discussed. The transfer of SSR markers across species or across genera can be a very efficient approach for DNA marker development, especially for minor crops.

Chickpea (Cicer arietinum L.) is an important crop for developed as well as underdeveloped countries, especially those in the Indian sub-continent that contribute more than 60% to both the global area and global production. The harsh environmental conditions under which chickpeas are generally grown impose restrictions on the expression of genetic yield potential. In the present study, a number of different breeding approaches for the development of genotypes possessing multiple resistances to different biotic and abiotic stresses, coupled with enhanced productivity are reported. In one study, 90 genetically diverse genotypes (35 medium-sized desi types, 35 bold-seeded desi types, 10 medium-sized kabuli types and 10 bold-seeded kabuli types) were tested in several locations in the 2000–2002 seasons, under rainfed (dryland) conditions and with supplemental irrigation. The bold-seeded desi genotypes gave superior performance in the rainfed environment, while the bold-seeded kabuli genotypes outyielded the other cultivars under supplemental irrigation. From crosses between accessions from geographically diverse sources, crosses between lines carrying multiple disease resistances, and crosses between the cultivated chickpea and the wild species, C. reticulatum, 23 selections were tested for yield and resistance to multiple stresses at various locations in northern and central India. From the crosses between geographically diverse parents, six high-yielding kabuli genotypes with wide adaptation and drought tolerance were identified. Pyramiding genes for multiple resistances proved useful in identifying eight lines possessing multiple disease resistance. Introgressing wild genes generated nine genotypes with high yield potential, resistance to soil-borne diseases and adaptation to water-limited environments. We conclude that high productivity, multiple resistance and wide adaptability can be achieved simultaneously by using potentially complementary approaches.

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

DNA profiles of 92 banana and plantain cultivars were generated with 12 amplified fragment length polymorphism (AFLP) primer pairs. The average polymorphism information content (PIC) values of the polymorphic AFLP markers varied from 0.270 to 0.341, and the profiles could distinguish all the 92 cultivars analysed. It was possible to identify differences between two accessions of the AAB genome cultivar Rasthali, indicating the presence of intra-cultivar genetic variation. A UPGMA (unweighted pair group method of arithmetical means) dendrogram generated with 1581 AFLP products identified four major clusters, each comprising cultivars of similar genomic constitution. All the ABB cultivars grouped in a single cluster, which was well separated from the rest. The within-group similarity coefficients indicated that the most diverse group was AAB, followed by AAA. However, significant genetic diversity was also present among AA, AB and ABB Indian banana cultivars, supporting the notion that India, along with other neighbouring south-eastern Asian countries, is the centre of diversity for cultivars of banana and plantain. The presence of substantial diversity among the banana and plantain landrace cultivars could be exploited in varietal improvement programmes.

Identification of sugarcane hybrids is difficult when selections are based solely on morphological traits. Our objective was to combine morphological traits and molecular marker analysis to select F1 hybrids from two separate crosses between Djatiroto, a clone of Saccharum spontaneum, and elite sugarcane clones, LCP 85-384 (Cross 97-3144) and CP 62-258 (Cross 97-3146). The maternal inflorescences of Djatiroto were emasculated by submersion in a circulating 45°C hot-water tank for 10 min to minimize self-fertilization. Cross 97-3144 produced 4.7 g of seeds with 338 viable seeds per gram and Cross 97-3146 produced 2.4 g of seeds with 166 viable seeds per gram. After greenhouse germination, 96 progeny from each cross were evaluated in a field plot. Evaluations were conducted on the ratoon crops for stalk diameter (mm), juice Brix (percentage soluble solids), and a randomly amplified polymorphic DNA (RAPD) marker OPA-11-366 that was reproducibly amplified through PCR from the elite clones, but not the maternal S. spontaneum clone. Fifty progeny (52.1%) from Cross 97-3144 and 36 progeny (37.5%) from Cross 97-3146 inherited the RAPD marker. Five putative F1 progeny were selected from each cross, namely US 99-43, US 99-44, US 99-45, US 99-46 and US 99-47 from Cross 97-3144, and US 99-48, US 99-49, US 99-50, US 99-51 and US 99-52 from Cross 97-3146, based on their relatively larger stalk diameter, higher Brix and inheritance of the RAPD marker. The hybrid nature of these selected progeny was verified with sugarcane microsatellite markers. This is the first report of the development of Saccharum hybrids with the cytoplasm of S. spontaneum for breeding purpose through a combination of conventional and molecular breeding approaches. Availability of these F1 hybrids could enhance the genetic diversity of Saccharum germplasm and has enabled sugarcane geneticists and breeders to explore the possible contribution of S. spontaneum cytoplasm in the development of new sugarcane cultivars.

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