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.

Graminaceous plants including staple cereals secrete certain phytosiderophores (PS) in calcareous soils with lower iron and zinc availability to enhance their uptake and translocation to the leaves and grains. A few Triticum aestivum cultivars and accessions of six Aegilops species were investigated for release of PS in vitro under iron- and zinc-sufficient and -deficient conditions, and for root and shoot iron and zinc concentrations. All the Aegilops species had three to four times higher release of PS than the wheat cultivars under both nutrient-sufficient and -deficient conditions. The maximum rate of increase of PS was observed on days 11 and 14 under iron- and zinc-deficient conditions, respectively, which levelled off rapidly among the wheat cultivars and continued to be high among Aegilops species till the end of the experiment. The absolute amount of iron and zinc expressed on dry weight basis after 18 d under iron- and zinc-deficient conditions showed nearly three times higher concentration in both roots and shoots of Aegilops species than that of the wheat cultivars. A significantly high correlation between concentrations of iron (r = 0.94) and zinc (r = 0.91) in roots and the PS released was found. The higher grain iron and zinc contents in the Aegilops species reported earlier may be attributed to their diverse and efficient mechanism(s) for PS-mediated micronutrient uptake and translocation system, which could be exploited for biofortification of wheat.

Spine gourd (Momordica dioica Roxb. ex Willd.) is a highly nutritious and underutilized vegetable containing high amount of protein as compared to other cucurbitaceous vegetables. Twenty-six accessions of spine gourd (M. dioica Roxb.), collected from eastern India, were evaluated to study the diversity and other genetic parameters. The estimates of genotypic coefficient of variation and phenotypic coefficient of variation for all the characters indicated that selection can be done on the basis of phenotype alone. On the basis of cluster analysis, spine gourd accessions can be categorized into three distinct groups. The accessions of spine gourd from eastern India showed an immense variation and can be used as a potential source of germplasm for crop improvement. The results presented here on nature and magnitude of genetic variability and diversity existing in this species will provide the foundation for designing an efficient spine gourd breeding programme. As spine gourd is distributed widely almost throughout India, further collections from Peninsular and Western India are suggested for maximum diversity sampling.

A total of 54 horsegram landraces collected from three altitudinal zones (lower hills, mid hills and higher hills) of Himalayan region were characterized and evaluated for nine quantitative characters. Accessions collected from lower and higher hills were more diverse and differed significantly from mid hills accessions for characters viz., days to flowering, days to physiological maturity, plant height and grain yield per plant. The plotting of first and second principal component axes scores revealed that there was dispersion among the accessions collected from different altitudinal groups. It reveals a less variability among the landraces collected from same altitudinal group but high variability among the landraces collected from different altitudes. This suggests that the horsegram landraces are adapted to specific zone due to different selection pressure practiced by the farmers at different altitudes. Farmers in lower and higher hills select the landraces having high grain yield coupled with less reproductive phase duration and taller in nature.

Target region amplification polymorphism markers were used to assess the genetic diversity and relationship among 151 worldwide collected faba bean (Vicia faba L.) entries (137 accessions maintained at the USDA–ARS, Pullman, WA, 2 commercial varieties and 12 elite cultivars and advanced breeding lines obtained from Link of Georg-August University, Germany). Twelve primer combinations (six sets of polymerase chain reaction) amplified a total of 221 markers, of which 122 (55.2%) were polymorphic and could discriminate all the 151 entries. A high level of polymorphism was revealed among the accessions with an estimated average pairwise similarity of 63.2%, ranging from 36.9 to 90.2%. Cluster analysis divided the 151 accessions into five major groups with 2–101 entries each and revealed a substantial association between the molecular diversity and the geographic origin. All 101 accessions in Group V are originated from China and 13 of the 15 accessions in Group II were from Afghanistan. Thirty-two individual plants were sampled from two entries to assess the intra-accession variation. It was found that the advanced inbred line (Hiverna/5-EP1) had very little variation (5.0%), while the original collection (PI 577746) possessed a very high amount of variation (47.1%). This is consistent with the previous reports that faba bean landraces have a high level of outcrossing in production fields and thus contain larger amount variation within each landrace. One implication of this observation for germplasm management is that a relatively larger population is needed in regeneration to mitigate the possible loss of genetic variation due to genetic drift.

Kenya lies within sorghum centre of diversity. However, information on the relative extent of diversity patterns within and among genetically defined groups of distinct ecosystems is lacking. The objective was to assess the structure and phenotypic diversity of wild sorghum populations across a range of geographical and ecological conditions in the country. Sixty-two wild sorghum populations (30 individuals per population) sampled from four distinct sorghum growing regions of Kenya and covering different agroecologies were characterized for ten qualitative traits. Plant height, number of tillers, panicle sizes and flag leaf dimensions were also recorded. Frequencies of the phenotypic classes of each character were calculated. The Shannon diversity index (H′) was used to estimate the magnitude of diversity. Principal component analysis was used to differentiate populations within and between regions. Wild sorghum is widely distributed in Kenya, occurring in sympatric ranges with cultivated sorghum, and both have overlapping flowering windows. All characters considered displayed great phenotypic diversity. Pooled over characters within regions, the mean H′ ranged between 0.60 and 0.93 in Western and Coast regions, respectively. Wild sorghum was found to show a weak regional differentiation, probably reflecting the importance of seed-mediated gene flow in shaping the wild sorghum population structure. Trait distribution was variable among regions, but there was no conspicuous distribution of the traits studied in any given region. Spontaneous hybridization and introgression of genes from cultivated to wild sorghum seems to be likely, and may already have occurred for a long time, although undocumented. Implications for in situ and ex situ genetic resources conservation are discussed.

Taxonomy plays an essential role in genebank documentation. It is often the first level at which users search material, and it determines the protocols used in the management of collections. Especially, when plant genetic resources information is pooled in systems such as EURISCO, the European catalogue of ex situ plant genetic resources, problems regarding technical handling of taxonomic nomenclature, such as lack of standardization and low quality of data, become apparent. These problems were studied by analysing the content of EURISCO and mapping the taxon names in EURISCO on those used in the United States Department of Agriculture genebank system GRIN-Tax. Thus, the number of spelling errors and the level of standardization could be quantified and improved. An analysis of the content of EURISCO was made, showing a highly unbalanced distribution over crops: 50% of the accessions belong to ten genera only. Mapping EURISCO on the crops listed in Annex 1 of the International Treaty on Plant Genetic Resources for Food and Agriculture showed that 67% of the accessions in EURISCO belong to crops in that list.

Production of summer squash, Cucurbita pepo, can be severely limited by viral pathogens and powdery mildew. Resistance has been introgressed from Cucurbita moschata, and resistant hybrids have been commercially deployed. Our objective was to assess genetic affinities of such hybrids with susceptible, open-pollinated cocozelle and zucchini cultivars, and two disease-resistant lines derived from six generations of backcrossing to a susceptible zucchini cultivar. Amplified fragment length polymorphism (AFLP) EcoRI/MseI primer combinations were employed and, based on the resulting polymorphic bands, genetic similarities were estimated, and an unweighted pair group method using arithmetic average (UPGMA) cluster analysis was conducted. The open-pollinated cocozelle cultivars clustered with the resistant hybrids. The hybrids had greater similarities with one another than did the open-pollinated cultivars. The zucchini cultivars and their resistant backcross lines formed their own exclusive cluster. However, the resistant backcross lines showed less than 0.80 similarity with their recurrent parent. As the chromosome number of Cucurbita is high (2n = 2x = 40) and the resistances are inherited monogenically and oligogenically, these results, after six generations of backcrossing, cannot be explained by classical genetic linkage.

Indian gooseberry, popularly known as amla, is harvested from two species of Phyllanthus, namely Phyllanthus emblica and Phyllanthus indofischeri. Although these two species are characterized on vegetative and reproductive features, development of reliable and authentic identification based on molecular approaches is necessary for precise identification. Most of the commercial orchards of Indian gooseberry are established with mixture of the two species. Introduction of unauthentic clones and seedlings in the establishment of orchards and differences in the growth of these two species under different elevations are the major constrains in identification. The present work aims to study the changes in vegetative and reproductive features under different elevations and to develop a simple molecular tool for precise identification of these two species based on single nucleotide polymorphisms in trnL (UAA) intron sequences of chloroplast DNA. Genomic DNA of leaf tissues of P. emblica and P. indofischeri, collected from the authentic source, was subjected to polymerase chain reaction amplification using trnL (UAA) intron gene-specific primers. The amplified product with the molecular weight of 540 bp was sequenced and used as reference for identification of these two species. The trnL (UAA) introns sequenced from 60 individual trees in three different orchards were compared with trnL (UAA) intron of authentic samples, and confirmed that these orchards have 76% population of P. indofischeri and remaining 24% is occupied by P. emblica. Thus, trnL (UAA) intron is a potential DNA marker for precise identification of these two species. The importance of the present study and its practical application in genetic improvement of Indian gooseberry are discussed.

Genetic variation in Lactuca serriola, the closest wild relative of cultivated lettuce, was studied across Europe from the Czech Republic to the United Kingdom, using three molecular marker systems, simple sequence repeat (SSR, microsatellites), AFLP and nucleotide-binding site (NBS) profiling. The ‘functional’ marker system NBS profiling, targeting disease resistance genes of the NBS/LRR family, did not show marked differences in genetic diversity parameters to the other systems. The autogamy of the species resulted in low observed heterozygosity and high population differentiation. Intra-population variation ranged from complete homogeneity to nearly complete heterogeneity. The highest genetic diversity was found in central Europe. The SSR results were compared to SSR variation screened earlier in the lettuce collection of the Centre for Genetic Resources, the Netherlands (CGN). In the UK, practically only a single SSR genotype was found. This genotype together with a few other common SSR genotypes comprised a large part of the plants sampled on the continent. Among the ten most frequent SSR genotypes observed, eight were already present in the CGN collection. Overall, the CGN collection appears to already have a fair representation of genetic variation from NW Europe. The results are discussed in relation to sampling strategies for improving genebank collections of crop wild relatives.

Pigeonpea (Cajanus cajan (L.) Millsp.) seed harvested while it is immature is a nutritious vegetable and forms a substitute for green pea [Pisum sativum (L.)]. Using the characterization data of more than 12,000 accessions conserved at ICRISAT genebank, Patancheru, India, 105 accessions were selected for important traits of vegetable pigeonpea (mature pod length>6 cm, seeds per pod>5 and 100-seed weight>15 g) and evaluated for these traits during 2007–08. From the initial evaluation, 51 accessions were identified as vegetable type and further evaluated for traits of vegetable pigeonpea during 2008–09 to identify most promising accessions. ICP 13831 produced longest immature pods (10.3 cm), ICP 13828 had maximum number of seeds per pod (5.9) and ICP 12746 produced larger seeds (44.8 g/100 seeds). Highest percentage of total soluble sugars (9.7%) was recorded in immature seeds of ICP 13413. ICP 15143 followed by ICP 15186 recorded more dry pods per plant and seed yield per plant. Performance of ICP 12184, ICP 13413, ICP 14085 and ICP 15169 was better than that of the best control for pod length, seeds per pod, soluble sugars and protein content. Cluster analysis based on scores of first five principal components resulted in three clusters that differed significantly for days to 50% flowering, days to 75% maturity, shelling percentage and soluble sugars. Important traits of vegetable pigeonpea such as immature pod length, seeds per pod, seed soluble sugars and protein content had shown strong positive correlation. Caribbean and Eastern Africa were found as the best source regions for vegetable pigeonpea. Evaluation of selected accessions at potential locations in different countries was suggested to identify vegetable pigeonpeas suitable for different regions and for use in crop improvement programs.

To characterize five different morphological forms of Russian olive grown in Ladakh, analysis of morphometric data of different variants was performed. Statistically significant differences among these variants were found for all the fruit and seed characters studied. Results of the study indicate presence of infra-specific differentiation within the species. Morphometric data for these variants conform to the system of nomenclature prevalent in the region for these variants. The ringmo (‘long fruited’ variety) type had the longest fruits, while bee (‘small fruited’ variety) had the smallest fruits.

Genetic structure of five populations of a locally common rice (Oryza sativa L.) landrace Jaulia from parts of Uttarakhand state of India was studied using sequence tagged microsatellite site (STMS) markers. Of these, four populations were on-farm managed, assembled from different niche environments, and one population was conserved ex situ and represented static conservation. The 16 STMS primer pairs fully differentiated the inter- and intrapopulation diversity. A total of 72 alleles were recorded with a mean of 4.5 alleles per locus. Population wise, the total number of alleles ranged from 21 to 41, with maximum number of alleles for population IC 548358 and minimum number of alleles for population IC 100051 representing static conservation. A greater number of alleles specific to populations under farmer management could be recorded. Changes in yield parameters also seemed to be affected under farmer management besides other environmental adaptations for qualitative morphological characters. The marker diversity using STMS primer pairs indicates the genetic differentiation among populations resulting from joint effects of several evolutionary forces operating within the historical and biological context of the crop landrace. The variations in adaptations, on the other hand, indicate the degree to which populations are adapted to their environments and their potential for continued performance or as donors of characters in plant breeding. Both biotic and abiotic aspects of the environment are involved.

Genetic diversity and phylogenetic relationships among 141 cowpea (Vigna unguiculata L. Walp.) accessions collected throughout the nine geographical regions of Ghana were evaluated using simple sequence repeat (SSR) molecular markers. Twenty-five primer combinations pre-selected by their ability to polymerase chain reaction amplify SSRs from a set of test cowpea germplasm were evaluated. Of these, 20 primer combinations gave reproducible polymorphisms among 97.2% of the cowpea accessions tested, with the remaining accessions being found to be genetically identical. The informative primer combinations revealed a total of 74 alleles at 20 loci with an average of 3.8 alleles detected per locus. Variation in heterozygosity among cowpea SSRs ranged from 0.01 to 0.84 with an average occurrence of 0.19. The polymorphism information content varied from 0.07 to 0.66 with an average of 0.38. The Ghanaian cowpea accessions clustered into five main branches, each of which was loosely associated with the geographical regions from which samples were obtained. Accession GH2288 was found to be the most divergent cowpea accession compared with all others including the outgroup IT84S-2049, a breeding line from Nigeria. Our results provide a framework for future studies aimed at the conservation and management of cultivated cowpea germplasm in Ghana, and a good starting point for the selection of parental lines for genetic improvement programmes.

This is the first report on increasing yield and nutritional content of snake melon (Cucumis melo L. var. flexuosus) by exploiting intraspecific genetic variation of genetically diverse melons. Inbred snake melon ‘Punjab Long melon 1’ (PLM1) was hybridized with five genetically diverse inbred melons: KP 7 (var. momordica), AM 72 (var. acidulus), ‘Arya 1’ (var. chate), 04-02 (var. tibish) and ‘Punjab Wanga’ (unknown botanical variety). The parents and hybrids were evaluated at three locations for nine traits. Hybrids PLM1 × 04-02 and PLM1 × ‘Punjab Wanga’ exhibited significant (P0.05) heterosis for the number of marketable fruits per plant, and ascorbic acid and carotenoid contents of marketable fruits.