Natural products from plants are still important sources for the development of drugs, despite their recent neglect in pharmaceutical discovery programmes. The rapidly dwindling number of species endangers the availability of these natural compounds, which are characterized by the immense chemical and functional diversity ultimately responsible for their pharmaceutical activity. Although many steps in the drug discovery process have been continuously modified during recent years, a common dilemma is still unresolved, i.e. the supply crisis for hits discovered in rare wild plants due to their inaccessibility or lack of reproducibility. New technology, combining tissue culture, functional genomics and metabolomics, shows promise to overcome these problems and even to supply a greater chemical diversity of compounds.

Thirteen wild plants and their food uses in the folk traditions of some regions of central Italy are described. These uses that can be exploited for human nourishment were collected during field research (1977–2003). Some wild food plants quoted are not very well known. The herbs have been selected for their peculiar organoleptic characteristics (Taraxacum apenninum, T. glaciale, Crepis leontodontoides), for their nutritional interest (Bunium bulbocastanum, Sinapis alba, Sonchus oleraceus, Taraxacum apenninum, T. glaciale) and the possibility of their cultivation in marginal areas (see Chenopodium bonus-henricus, Podospermum canum, P. laciniatum and some of the quoted species).

A civil war is being fought in Darfur in western Sudan that has resulted in a humanitarian disaster with large numbers of Sudanese refugees seeking a safe haven in neighbouring Chad. The conflict is largely ecological in origin and is based on competition for natural resources, including plant genetic resources. Western Sudan has relatively low rainfall and supports rainfed sedentary agriculture and nomadic pastoralism, and a range of domesticated plant species is grown under irrigation by seasonal watercourses. Nomadic pastoralist populations move their herds according to established routes of seasonally available range and pasture species. There has always been a delicate balance between the sedentary and nomadic ways of life that through careful use of water and plant genetic resources has maintained the ecology of the region in balance. Drought, deforestation, overpopulation and overgrazing have accelerated desert encroachment and have exerted huge pressures on the ecology of the region. Indigenous plant genetic resources, including many wild species used as famine foods, are the key to livelihoods in the region. The upsurge in violence has resulted in many farmers abandoning their farms and seed stocks. Social systems are disrupted and rehabilitation of agriculture will be very difficult. This article describes domesticated and wild plant genetic resources of southern Darfur and details their importance to livelihoods in the region.

As a member of the tribe Brassiceae, Eruca sativa, although a minor crop worldwide, is considered a valuable genetic resource for cabbage, rapeseed and other Brassica crops. Self-incompatibility (SI) in Brassica has been extensively studied, but information on SI in E. sativa is limited. Of six chemicals used to treat the stigmas to overcome SI in five E. sativa lines, gibberellin was the most effective. As gibberellin is well known for its ability to break dormancy and to promote cell elongation, its effectiveness may help to understand the mechanisms of SI. Urea and ammonium sulphate were also effective. These two chemicals are known to affect protein stability, which may help explain their effects on SI. Although table salt has been reported as being effective in overcoming SI in B. rapa, B. oleracea and B. napu, it was not effective in E. sativa. Sucrose and alcohol also had negligible effect. There was significant variation among the genotypes in SI intensity and response to chemicals, but the genotype–chemical interaction was not significant. The data presented in this paper add to our understanding of SI in E. sativa and may lead to a better use of this genetic resource.

Due to their complex structure with several chiral centres important anticancer agents are still extracted from plants and not synthesized chemically on a commercial scale. Sustainable bioproduction of the compounds of interest may be achieved by plant in vitro cultures. Undifferentiated callus and suspension cultures, which can be cultivated in large bioreactors easily, very often fail to accumulate the compounds of interest, whereas shoot and root cultures as well hairy roots normally produce the same compounds as in the appropriate organs. The production of anticancer compounds, such as the alkaloids vinblastine, vincristine, paclitaxel (Taxol®), camptothecin, or the lignan podophyllotoxin, by plant in vitro cultures is reviewed. Taxanes can be produced in bioreactors using cell suspensions of various Taxus species with good yields; presently paclitaxel is produced on a commercial scale by Phyton Biotech (Germany). Camptothecin has low yields in suspension cultures of Camptotheca acuminata or Nothapodytes foetida (0.0003–0.01%), but a good production (0.1–0.3% dry wt) in root and hairy root cultures of Ophiorrhiza pumila, O. mungos and C. acuminata. Podophyllotoxin can be produced in cell suspension and root as well as hairy root cultures of Podophyllum and various Linum species up to 130 mg/l (Linum album cell suspensions); its derivative 6-methoxypodophyllotoxin is accumulated in hairy roots of L. persicum up to about 500 mg/l. The in vitro production of dimeric indole alkaloids in Catharanthus roseus has failed so far both in undifferentiated and differentiated in vitro cultures. In cases where in vitro cultures show good yields, they can be employed in biotechnology for the sustainable production of valuable products.

The bell-type pepper cultivar Golden California Wonder, a source of resistance to southern blight, was crossed with the susceptible cultivar Sweet Banana. The F1, F2 and backcross progenies of this cross and the parental lines were evaluated in an inoculated field study for their reactions to Sclerotium rolfsii Sacc. A categorical rating system was used to rate plants for severity of wilting and severity of stem-lesion development. The plants within all three non-segregating populations (the resistant parent, the susceptible parent and the F1) displayed a range of reactions to S. rolfsii. Variable reactions to S. rolfsii among homogeneous pepper populations were expected because this phenomenon is well documented in the literature and we had observed similar responses in field trials conducted over multiple years. The high level of variation for reactions to S. rolfsii exhibited by the parental and F1 hybrid populations and the categorical system of rating individual plants placed severe limitations on the effective use of any quantitative type of analysis. Accordingly, a weighting procedure was used to correct the F2 and backcross populations based on frequencies of apparent mis-classifications in the parental and F1 populations. Examination of the comparative frequency distributions of the parental and progeny populations and examination of the weighted segregation data suggest that the southern blight resistance in ‘Golden California Wonder’ is conditioned by a single recessive gene. The level of resistance conditioned by this reputed recessive gene appears high enough to recommend it for use in pepper breeding programmes.

The Sorghum genus is extremely diverse both morphologically and geographically, however, relatively few of the 25 recognized species have been evaluated genetically. The apparent lack of basic knowledge pertaining to the levels of genetic diversity both within and between the 17 Australian wild species is a major obstacle to both their effective conservation and potential use in breeding programmes. Twelve Sorghum bicolor-derived simple sequence repeat (SSR) markers were evaluated for cross-species amplification in all 25 Sorghum species. The SSR markers were highly polymorphic, with diversity indices ranging from 0.59 to 0.99 with mean of 0.91. Five markers combined were able to differentiate 24 of the 25 Sorghum species, with intra-species polymorphism apparent. Sorghum bicolor-derived SSRs have proven to be an efficient source of markers for genetic diversity studies of the relatively poorly characterized Australian indigenous Sorghum species.

We analysed the patterns of variation for 14 qualitative and 12 quantitative traits in 11,402 pigeonpea germplasm accessions from 54 countries, which were grouped into 11 regions. Semi-spreading growth habit, green stem colour, indeterminate flowering pattern and yellow flower colour were predominant among qualitative traits. Primary seed colour had maximum variability and orange colour followed by cream were the two most frequent seed colours in the collection. Variances for all the traits were heterogeneous among regions. The germplasm accessions from Oceania were conspicuous by short growth duration, short height, fewer branches, pods with fewer seeds, smaller seed size and lower seed yields. The accessions from Africa were of longer duration, taller, with multi-seeded pods and larger seeds. The germplasm diversity indicated by Shannon–Weaver diversity index (H′) pooled over all traits, was highest for Africa (0.464±0.039) and lowest for Oceania (0.337±0.037). The cluster analysis based on three principal component scores using 12 quantitative traits revealed formation of three clusters: cluster 1 includes accessions from Oceania; cluster 2 from India and adjacent countries; and cluster 3 from Indonesia, Thailand, the Philippines, Europe, Africa, America and the Caribbean countries. Pigeonpea-rich countries such as Myanmar, Uganda, and others like Bahamas, Burundi, Comoros, Haiti and Panama are not adequately represented in the collection, and need priority attention for germplasm exploration.

In China, medicinal plants enjoy an inherent and prominent role in the general health service. Due to excessive collection in the wild of rare and endangered plants, the natural resources of medicinal plants are depleting fast. In order to protect the medicinal plant resources, the Chinese government has implemented Good Agricultural Practice (GAP) programmes to cultivate the main popular medicinal plants in China. Thus far, around 800 GAP cultivation bases have been established nationwide and the total cultivation area of medicinal plants has reached 5000 km2. Besides GAP cultivation of medicinal plants, tissue cultural biotechnology has been applied to serve as an alternative for the supply of medicinal plant materials in China. Thus far, shoot production by tissue culture technology has been successful in medicinal plants such as Anoectochilus formosanus, Dalbergia odorifera, Dendrobium, Momordica grosvenorii, Pseudostellaria heterophylla and Taxus chinensis. In addition, the cell culture of Lithospermum erythrorhizon and Saussurea involucrata has been industrialized in 300–20,000-litre bioreactors. Besides the production of shoot and cell culture in bioreactors, tissue culture technology is also being practised for the conservation of rare medicinal plants.

In order to describe the phenotypic diversity in a core collection of grasspea, 47 progenies of single plants (pure lines) selected from 25 accessions were evaluated. Sixteen morpho-agronomic characters including seed 3-(β-N-oxalyl)-l-2,3 diaminopropionic acid (β-ODAP) content were studied. Univariate and multivariate analyses (principal component analysis and cluster analysis) were performed to estimate differences between progenies. Some high-yielding lines could be used directly for cultivation as new varieties and/or as parental lines in crossing programmes. Seed β-ODAP concentration varied from 0.24% to 0.64%. However, a medium to high seed β-ODAP level was recorded for most of the lines, and no significant correlation was observed between this and other morphological traits.

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

We report the morphological typing of 13,337 accessions of bread wheat. The individual characters assessed were: awnedness, awn colour, glume colour, presence/absence of glume hairs, spike type, spike density, spike branching, grain colour, stem type (hollow/solid) and presence/absence of ligules. We have associated these morphological data with accession provenance, to analyse global patterns of the traits. Whereas some of the traits (awnedness, awn colour, glume colour, presence/absence of hairs on glumes, stem type) are concentrated in distinct geographical regions, others (spike type, spike density, grain colour, presence/absence of ligules) appear to be randomly distributed. Spike branching was not observed. Possible reasons for the geographical distributions of the characters, in the light of their inheritance, are discussed.

The phenotypic diversity of 32 landrace populations of tetraploid wheats originating from the Bale and Wello regions of Ethiopia was studied. Eight heritable qualitative traits (glume hairiness, glume colour, awnedness, awn length, beak awn, awn colour, spike density, seed colour) were measured on 2453 individual plants (45–110 plants per landrace). The frequencies of each phenotypic class were used to estimate and analyse the diversity at different levels (population, altitude, region). Beak awn and seed colour showed the highest diversity index, and glume hairiness the lowest. Glume hairiness, glume colour, beak awn and awn colour were regionally variable, while gradients across altitude were observed for glume hairiness, glume colour and beak awn. Variation was, however, largely due to the differences in the level of the different characters within populations. On a regional basis, a higher mean diversity index was observed for materials from Wello than from Bale. No drastic change in the overall diversity between these collections and those analysed in the 1970s was evident.

The endangered alpine plant Aconitum heterophyllum was conserved under ex situ conditions (greenhouse and open) of Palampur by overcoming seed dormancy and plant establishment through hot water treatment (40–60 °C for 30–120 s) of seeds. High seed germination (88 and 76%) was obtained when seeds were treated with hot water at 45 and 50 °C for 90 s. Correlation studies also revealed that treatment enhanced vegetative growth and reproductive yield of the plants. The total alkaloid content of the roots and rhizomes of the plants growing under ex situ conditions was lower than the ones collected from the natural habitat in the 1-year-old plants. However, in the 2-year-old plants, it was almost at par with the ones collected from nature. The life cycle of the plants growing under ex situ conditions also did not vary largely from the plants growing under in situ conditions. Therefore, the present study indicates the successful adaptation of A. heterophyllum plants in conditions other than their natural habitat and hence its potential for sustainable commercialization.

Awareness of the need for biodiversity conservation is now universally accepted, but most often recent conservation activities have focused on wild species. Crop species and the diversity between and within them has significant socioeconomic as well as heritage value. The bulk of genetic diversity in domesticated species is located in traditional varieties maintained by traditional farming systems. These traditional varieties, commonly referred to as landraces, are severely threatened by genetic extinction primarily due to their replacement by modern genetically uniform varieties. The conservation of landrace diversity has been hindered in part by the lack of an accepted definition to define the entity universally recognized as landraces. Without a definition it would be impossible to prepare an inventory and without an inventory changes in landrace constituency could not be recognized over time. Therefore, based on a literature review, workshop discussion and interviews with key informants, common characteristics of landraces were identified, such as: historical origin, high genetic diversity, local genetic adaptation, recognizable identity, lack of formal genetic improvement, and whether associated with traditional farming systems. However, although these characteristics are commonly present they are not always all present for any individual landrace; several crop-specific exceptions were noted relating to crop propagation method (sexual or asexual), breeding system (self-fertilized or cross-fertilized species), length of formal crop improvement, seed management (selection or random propagation) and use. This paper discusses the characteristics that generally constitute a landrace, reviews the exceptions to these characteristics and provides a working definition of a landrace. The working definition proposed is as follows: ‘a landrace is a dynamic population(s) of a cultivated plant that has historical origin, distinct identity and lacks formal crop improvement, as well as often being genetically diverse, locally adapted and associated with traditional farming systems’.

A major challenge for the molecular characterization and evaluation of minor grass species germplasm is the lack of sufficient DNA markers. A set of 210 simple sequence repeat (SSR) markers developed from major cereal crops (self-pollinated wheat and rice, mainly self-pollinated sorghum and out-crossing maize) were evaluated for their transferability to minor grass species (finger millet, Eleusine coracana; seashore paspalum, Paspalum vaginatum; and bermudagrass, Cynodon dactylon). In total, 412 cross-species polymorphic amplicons were identified. Over half of the primers generated reproducible cross-species or cross-genus amplicons. The transfer rate of SSR markers was correlated with the phylogenetic relationship (or genetic relatedness) of these species. The average transfer rate of genomic SSR markers was different from the average transfer rate of expressed sequence tag (EST)-SSR markers. The level of polymorphism was significantly higher among species (67%) than within species (34%), and was related to the degree of out-crossing for each species. The level of polymorphism detected within species was 57% from self-incompatible species, 39% from out-crossing species and 20% from self-pollinated species. Genomic SSRs detected a higher level of polymorphism than EST-SSRs. The use of transferred polymorphic SSR markers for the characterization and evaluation of germplasm is discussed.