Evaluation of phenotypic variation in a worldwide germplasm collection of safflower (<Emphasis Type="Italic">Carthamus tinctorius</Emphasis> L.) grown under organic farming conditions in Germany

An investigation was conducted to determine the extent of diversity and relationships among a worldwide safflower (Carthamus tinctorius L.) germplasm collection and to find out adapted accessions that can be used in an organic safflower breeding program in Germany. A total of 468 accessions was studied under organic farming conditions at Kleinhohenheim experimental station during the seasons of 2004 and 2005. All the accessions were evaluated for 12 phenotypic traits and three rated diseases. Multivariate analyses have been used to measure the diversity in a subset of 200 accessions and 11 geographical regions. Generally, the study showed that there was a large genetic variation within accessions. A coefficient of variation (CV%) for investigated traits and diseases ranged from 2.9 to 91.0% with the highest CV was recorded for yield/m2, yield/plant and seeds/plant. The most accessions that originated in Europe revealed relatively better performance compared to non-Europeans. High yielding, early maturing, and disease tolerant accessions were identified. However, the low oil content (8.7–22.8%) is the primary concern in this germplasm collection. The degree of heritability varied between 10% for lodging to 86% for plant height. Genotypic coefficient of correlation (r _g) was slightly higher for many traits than the respective phenotypic coefficient. Oil content and seed yield/m2 were highly significantly correlated (r _g = 0.78). The genotypic coefficient of correlation showed that selection for seeds/plant and thousand kernel weight was effective for improvement of seed yield and oil content. The results of the principal component analysis and the clustering pattern of accessions were consistent with the results of analysis of variance. About 78% of the total phenotypic diversity in the germplasm was explained on the basis of four principal components and 88% of the total variation among geographical regions was contributed by the first three principal components. The distribution of the accessions within clusters has no apparent relationship with the geographical origin. However, many of the European accessions have a tendency to stay together.     

Variability and selection on different <Emphasis Type="Italic">Argyrolobium roseum</Emphasis> accessions for morphological traits and yield

Variability studies were carried out among different accessions of Argyrolobium roseum for 12 metric traits under natural and cultivated conditions. Almost all characters showed higher values in cultivated than natural population. Leaf breadth recorded highest CV (30.59%). Highest percentage of vitexin and D-pinitol (0.208 and 0.773% dwb) was observed in RAR-7 and RAR-6, respectively, under cultivated conditions. Phenotypic coefficient was higher than genotypic coefficient of variation. The association analysis revealed that root yield had positive significant correlation with 100 seed weight (r=0.839) biomass yield (r=0.601), where biomass yield had a positive significant correlation with leaf length, single pod weight. High heritability (97.4–99.8%) coupled with moderate genetic advance ranged between (49–67%) as a percent of mean was observed for leaf breadth, pod length, total foliage biomass yield and total root yield/plant. This suggests that direct selection for these traits is suitable for the improvement of this crop.     

Genetic relationships among cultivated types of Perilla frutescens and their weedy types in East Asia revealed by AFLP markers

AFLP markers were employed to detect genetic diversity in two cultivated Perilla frutescens (i.e. var. frutescens and var. crispa) and their weedy types and to assess their genetic relationships. Analysis of 60 Perilla accessions from China, Korea and Japan by seven AFLP primer combinations identified a total of 125 fragments, of which 80 (64%) were polymorphic at the species level. The phenotypic diversity meassured by Shannon's index of information for the cultivated type of var. frutescens, the weedy type of var. frutescens, the cultivated type of var. crispa and the weedy type of var. crispa were on average 1.07, 2.23, 1.24 and 1.75, respectively. The weedy types exhibited high within-type variation in spite of a small number of samples. In the neighbor joining tree, two major clusters were recognized: (1) cultivated type of var. frutescens, (2) weedy type of var. frutescens, and cultivated and weedy types of var. crispa. The cultivated types of var. frutescens and of var. crispa were sharply separated by AFLPs. However, there remained ambiguities in regard to the intraspecific relaltionships, due to the clustering of the weedy types which occured in each of the clusters of the cultivated types. Two cultivated types of P. frutescens and their weedy types should be taxonomically considered as a P. frutescens complex. The present AFLP data are consistent with the hypothesis that China is the original place of cultivation of var. frutescens and Korea is a secondary center of diffusion of var. frutescens.     

Genetic variation in wild and cultivated artichoke revealedby RAPD markers

Determination of intraspecific genetic diversity is an important first step for the utilization of genetic resources and canprovide useful information on crop evolution. A living collection of Italian and foreign artichoke varieties and ecotypes is maintained at the Germplasm Institute, Bari, Italy. A total of 32 accessions of cultivated (Cynara cardunculus L. var.scolymus (L.) Fiori), three of wild (Cynara cardunculus var.cardunculus L.) artichoke and two ofcultivated cardoon (Cynara cardunculus var.altilis L.) were analysed in order to studygenetic variation and relationships within the species, using RAPDmarkers. Cultivated accessions were selected according tomorphological variation and geographical distribution available inthe collection. Fifty arbitrary decamer primers were initially tested, 18 ofwhich showed from 3 to 10 unambiguously interpretable fragments. Anintra-accession analysis using 4 varieties and 8 polymorphicprimers revealed that no RAPD variation was detected amongindividuals. Jaccard's similarity index (JSI) was comprisedamong 1 and 0.693 when all accessions were considered, on the otherhand, within the cultivated artichoke, JSI ranged between 1 and0.817. A UPGMA dendrogram based on the similarity matrix showed thatwild artichokes were clearly separated from cultivated accessions.Moreover, within cultivated artichokes, several groups could bedistinguished.     

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.     

Allelopathy variation in dryland winter wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) accessions grown on the Loess Plateau of China for about fifty years

In this study, we investigated the genetic variation of allelopathic potential, its grey correlation with important agronomic characters, and rank analysis on allelopathic stability of fifteen wheat accessions commonly grown in arid regions of the Loess Plateau in China. The genetic variation of allelopathic property in dryland winter wheat showed significant differences between accessions. Allelopathic effects exhibited high heritability (55–95%) throughout the life cycle of wheat. Heritability was highest in the tillering stage and weakest in the seed filling stage. Allelopathic potential varied and was discontinuous throughout the wheat life cycle. Grey correlation analysis indicated a close relationship between allelopathic potential dependant on growth phase and agronomic characters. Allelopathic expression during some growth periods induced a partial correlation effect on some important agronomic characters that affected wheat yield. Allelopathic heritability and its degree of influence on yield were more evident in the vegetative growth stage compared to the reproductive stage. A multiple linear regression was built between allelopathic potential during different growth periods and agronomic characters pursued in wheat breeding. Allelopathic potential had a linear effect on production traits cultivated in wheat breeding. When allelopathic intensity varied from 0 to 1 in the reproductive stage, plant height ranged from 44 to 108 cm, spike length from 6.4 to 9.2 cm, number of spikelets with seeds from 13.4 to 21.0, mean seed number per spike from 41.5 to 50.3 and thousand seed weight from 36.2 to 38.3 g. Based on rank analysis, we concluded that there was a synergistic relationship between allelopathic potential in wheat and genetic, chemical and ecological factors. Triticum aestivum L. ‘No 6 Lankao’ and T. aestivum L. ‘No 22 Xiaoyan’ were identified as stable and relatively strong allelopathic accessions, whereas T. aestivum L. ‘Lankao 95–25’ was a stable but relatively weak allelopathic cultivar. Other varieties showed unstable allelopathic potential.     

Variation and heritability of seed mass in chia (<Emphasis Type="Italic">Salvia hispanica L.</Emphasis>)

Variation and heritability of seed mass in the Mesoamerican crop chia, Salvia hispanica L. was studied to examine the feasibility of selection for the trait. Genotypic variation in seed mass in wild/cultivated and domesticated accessions of chia from different origins was assessed. Broadsense heritability of seed mass was estimated using variances associated with parental and F2 generations derived from two crosses and from the response to one cycle of selection. Significant (P . 0.0001) genotypic variation was observed among accessions. Mean seed mass for domesticated accessions (14.84 mg/100 seeds) was greater than that of the wild accessions (11.29 mg/100 seeds) by 31%. The heritability of seed mass was relatively high in chia (0.75), suggesting that this trait is under strong genetic control. This conclusion was supported by a single selection cycle from the F2 to F3 generation that produced a 16% increase in mean seed mass. The realized heritability estimated based on this one cycle of selection also was 0.75. These observations indicate that gains from selection in chia seed mass are possible when mass selection is conducted in early generations. Basic information is thus provided for future breeding efforts in a species for which little or no knowledge of inheritance currently exists.     

Molecular characterization of genetic diversity,structure, and differentiation in the olive (<Emphasis Type="Italic">Olea europaea</Emphasis> L.) germplasm collection of the United States Department of Agriculture

Fifteen microsatellite loci were used to genotype 108 accessions of cultivated olive, Olea europaea L. ssp. europaea var. europaea, and eight of O. europaea L. ssp. cuspidata (Wall. ex G. Don) Ciferri, from the germplasm collection of the United States Department of Agriculture in Davis, California. Number of alleles per locus ranged from 3, for locus IAS-pOe12_A, to 16, for locus ssrOeUA-DCA11, with an overall mean of 9.93. Observed heterozygosity ranged from 0.175, for locus UDO99–019, to 0.937, for locus GAPU89, with a mean of 0.640. The cluster analysis using the Unweighted Pair Group Method using Arithmetic mean (UPGMA) method displayed thirteen clusters within seven main groups that can be partially described by common geographic origin or fruit use, though overlap among these groups was common. The locus-wise total gene diversity (H _T) ranged from 0.319, at UDO99–019, to 0.847, at ssrOeUA-DCA3, with an overall mean of 0.696. Most of the gene diversity was partitioned within clusters, with proportions (H _S/H _T) ranging from 0.633, at IAS-pOe12_B, to 0.848 at GAPU89 per locus, with a mean of 0.759. The principal components analysis explained 24.8% of the total variation along the first two components. Projection of accessions onto the first two principal components produced affinities generally in agreement with the results of the UPGMA cluster analysis. The California cultivar ‘Mission’ clustered closely with Iberian cultivars and may represent clonal selections adapted to local growing conditions. The results show significant diversity but low levels of differentiation among olive cultivars within the collection.     

A multi-species assessment of genetic variability in Nigerian Amaranthus accessions: potential for improving intra- and interspecies hybridization breeding

Amaranthus yields could benefit from our growing understanding of the genetic variability within and among individual species of local germplasm collections. Thirty-seven Amaranthus accessions representing three different species were evaluated for seed yield and yield components across two seasons. The objectives were to characterize the genetic variability of seed yield and its components across species and determine relationships among seed yield and its components by phenotypic correlation. Significant differences (P < 0.01) existed for all the evaluated traits among the accessions. Characters such as seed yield, stem girth and leaf length showed higher heritability estimates in A. cruentus (14) than in A. hypochondriacus (12) and A. dubius (11) accessions. Seed yield was significantly and positively correlated with stem girth and thousand seed weight. However, it was significantly and negatively correlated with number of days to flowering, plant height, leaf number, number of branches. The clustering of the accessions, which was partially in agreement with species grouping, will help in the identification of diverse parents for use in the breeding program. Enormous amount of genetic variability found in seed yield and its components among Nigerian Amaranthus accessions will offer opportunity for grain and leaf yield improvement through breeding.     

Characterization of sesame (<Emphasis Type="Italic">Sesamum indicum</Emphasis> L.) germplasm regenerated in Georgia,USA

Sesame, Sesamum indicum L. is used worldwide for cooking oil and food. The United States Department of Agriculture, Agricultural Research Service, Plant Genetic Resources Conservation Unit (USDA, ARS, PGRCU) conserves 1,226 accessions originating from Europe, Africa, Asia, North America, and South America. Sesame accessions were directly seeded to the field in Griffin, GA between 15 May and 01 June 2003–2007. At 50% maturity, 192 accessions were characterized for morphological, phenological, and reproductive traits during the regeneration cycles. High quality plants regenerated from all accessions produced 131 to more than 80,000 seeds per accession. Sesame can be successfully grown and regenerated in Griffin, GA. Coefficients of variation and principal component analysis revealed considerable variability among accessions for phenological, morphological and reproductive traits. Assuming appropriate levels of heritability, sufficient variation among sesame accessions exists for days to maturity, plant height, and reproductive traits among these sesame accessions to warrant breeding programs for new sesame cultivar development.     

Variation of cultivated flax (Linum usitatissimum L. subsp.usitatissimum) and its wild progenitor pale flax (subsp.angustifolium (Huds.) Thell.)

The domestication of cultivated flax (Linum usitatissimum L. subsp.usitatissimum) is briefly discussed. Using data documented as a matter of routine in genebank work, 63 accessions of cultivated flax from the flax germplasm collection of the Gatersleben Genebank are compared with 73 accessions of its wild progenitor pale flax (subsp.angustifolium (Huds.) Thell.), which have been observed in systematic field trials. Range of variation, genetically based variation, heritability and correlation of several characters are considered, especially with respect to the influence of domestication. Cultivated flax shows higher variation in the characters of generative plant parts, while pale flax varies more in the vegetative parts of the plant. The character correlations are similar in both subspecies. Of the 29 characters studied in pale flax the parameters describing tillering, height of plant, weight of seeds, width of petals and width of leaves are especially suitable for distinguishing between different accessions. In spite of the high heritabilities of most of the characters, the influence of the environment is significant in most cases.     

Assessment of Genetic Diversity among Finger Millet (<Emphasis Type="Italic">Eleusine coracana</Emphasis> (L.) Gaertn.) Accessions using Molecular Markers

Finger millet (Eleusine coracana), an allotetraploid cereal, is widely cultivated in the arid and semiarid regions of the world. Being rich in protein and calcium, finger millet serves as an important staple food for rural populations in developing tropical countries where calcium deficiency and anemia are wide spread. Thirty-two finger millet genotypes were fingerprinted using 50 random amplified polymorphic DNA (RAPD) markers. Out of the total 529 loci generated using the 50 RAPD primers, 479 loci (91%) were polymorphic and informative to differentiate the accessions. Cluster analysis grouped the 32 finger millet accessions into two major clusters. Among the 32 finger millet genotypes, GEC 182 and CO 12 were distantly related with a low similarity index of 0.315. These two accessions also differed considerably in days to flowering and grain weight; GEC 182 is early flowering and has bold grains, while CO 12 is late flowering and has smaller grains. These two accessions with higher diversity at molecular level, phenology and grain weight will be ideal as parents in hybridization programme, to develop improved finger millet varieties suitable for peninsular region of India.     

The genetic characterization of Turkish watermelon (<Emphasis Type="Italic">Citrullus lanatus</Emphasis>) accessions using RAPD markers

Genetic diversity of the Turkish watermelon genetic resources was evaluated using different Citrullus species, wild relatives, foreign landraces, open pollinated (OP) and commercial hybrid cultivars by RAPD markers. The germplasm was consisted of 303 accessions collected from various geographical regions. Twenty-two of 35 RAPD primers generated a total of 241 reproducible bands, 146 (60.6%) of which were polymorphic. Based on the RAPD data the genetic similarity coefficients were calculated and the dendrogram was constructed using UPGMA (Unweighted pair-group method with arithmetic average). Cluster analysis of the 303 accessions employing RAPD data resulted in a multi-branched dendrogram indicating that most of the Turkish accessions belonging to var. lanatus of Citrullus lanatus (Thunb.) Matsum et Nakai were grouped together. Accessions of different Citrullus species and Praecitrullus fistulosus (Stocks) Pangalo formed distant clusters from C. lanatus var. lanatus. Among 303 accessions, a subset of 56 accessions was selected representing different groups and a second dendrogram was constructed. The genetic similarity coefficients (GS) within the Turkish accessions were ranged from 0.76 to 1.00 with 0.94 average indicating that they are closely related. Taken together, our results indicated that low genetic variability exist among the watermelon genetic resources collected from Turkey contrary to their remarkable phenotypic diversity.     

AFLP similarities among historic Danish cultivars of fodder beet (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L. subsp. <Emphasis Type="Italic">vulgaris</Emphasis>var. <Emphasis Type="Italic">rapacea</Emphasis> Koch)

Dead seeds of a fodder beet cultivar ‘Elvetham’ stored under ambient conditions since 1880 were compared to a homonymous sample preserved in an on-farm situation in Denmark. DNA was isolated from single seeds and successfully applied to Amplified Fragment Length Polymorphism (AFLP) analysis of the accessions. Six primer pairs were used to determine the similarity between the two accessions based on 112 polymorphic bands. Furthermore, similarity among seven cultivars of fodder beets representing the main types used in Scandinavia at the end of the 19th century was determined. This analysis was based on 152 polymorphic bands. Differentiation among the seven cultivars was determined to a mean G _ST value of 0.438, while G _ST between the two ‘Elvetham’ accessions was 0.266. A principal coordinate analysis based on jaccards similarity index illustrates that the two ‘Elvetham’ accessions are different from each other. The differentiation is higher than the value found between two separate ‘Eckerndorfer’ accessions. The results indicate that the cultivated accession has changed. Additionally, the value of applying old dead seed material for documentation in gene banks is demonstrated. During the analysis it was found that DNA isolated from seeds and leaves behaved differently in the AFLP process, however, the two fractions assigned to their common accession.     

Diversity and origin of cultivated and citron type watermelon (<Emphasis Type="Italic">Citrullus lanatus)</Emphasis>

Cultivated (Citrullus lanatus var. lanatus) and citron type (var. citroides) watermelon collected from different areas on the African continent are remarkably diverse in fruit and seed morphology. Chloroplast DNA investigations using PCR-RFLP and sequencing analysis of several non-coding regions were conducted to infer their biogeographic and evolutionary relationships, origin and domestication history. Variability within C. lanatus was observed at regions of high A + T content, resulting in indels and transversions mainly. Distinct chlorotype lineages were identified separating the cultivated and egusi-type watermelon from var. citroides accessions. This suggests an ancient split from a common ancestor and haplotype fixation. Three haplotypes as a result of relatively recent indel events were detected within var. citroides. The geographical range of two of the main citroides haplotypes is relatively similar across southern Africa. Accessions with the most ancient citroides haplotype originated in Swaziland and South Africa resulting in colonization routes from this area all over the world. Chloroplast divergence is not associated with morphological divergence. The cultivated and wild watermelon appear to have diverged independently from a common ancestor, possibly C. ecirrhosus from Namibia.     

Genetic diversity and structure of Ethiopian,Yemen and Brazilian C<Emphasis Type="Italic">offea arabica</Emphasis> L. accessions using microsatellites markers

Genetic diversity among 115 coffee accessions from the Coffea Germplasm Collection of IAC was assessed using SSR markers. The germplasm represents 73 accessions of Coffea arabica derived from spontaneous and subspontaneous plants in Ethiopia and Eritrea, species center of origin and diversity, 13 commercial cultivars of C. arabica developed by the Breeding Program of IAC, 1 accession of C. arabica cv. ‘Geisha’, 13 accessions of C. arabica from Yemen, 5 accessions of C. eugenioides, 4 accessions of C. racemosa and 6 accessions of C. canephora. Genetic analysis was performed using average number of alleles per locus (A), proportion of polymorphic loci (P), Shannon’s genetic index (H′ and G′_ST) and clustering analysis. All evaluated species were distinguished by a cluster analysis based on Jaccard’s coefficient. Differentiation between the cultivated plants of C. arabica and accessions derived from spontaneous and subspontaneous plants was observed. Spontaneous and subspontaneous accessions from Ethiopia were separated according to the geographical origin: east and west of the Great Rift Valley. Cultivated plants showed a low genetic diversity with a division in two groups: accessions from Yemen (H′=0,028) and Brazilian commercial cultivars (H′=0,030). The results agreed with previously reported narrow genetic basis of cultivated plants of C. arabica and supported the hypotheses about domestication of the species. This study also showed a significant genetic diversity among accessions from Ethiopia and Eritrea present in the Germplasm Collection of IAC. This diversity is specially observed in accessions from Sidamo (H′=0,143), Kaffa (H′=0,142) and Illubabor (H′=0,147) indicating their importance as source of genetic variability for coffee breeding programs.     

Characterisation of agro-morphological traits of corchorus accessions

The genus Corchorus includes nutrient-rich indigenous leafy vegetables often grown or harvested in the wild in Africa. It has potential to contribute to food security, but there is need to improve it as a crop through plant breeding. However, not much is known about the genetic variability among Corchorus species. The aim of this study was thus to characterise the available germplasm of Corchorus accessions and investigate heritability of their agro-morphological traits. Eleven Corchorus accessions (4 South African and 7 from the World Vegetable Center) were evaluated in a field study at Roodeplaat, South Africa, for their morpho-agronomic traits using a randomised complete block design with three replications across two seasons (2015/2016 and 2016/2017). Data were subjected to ANOVA, principal component analysis and cluster analysis. Broad sense heritability, genetic advance, genetic parameters and correlations were determined among the accessions and traits. The Corchorus accessions showed significant (P < .05) differences in all the quantitative traits evaluated. The data showed significant variability among the studied Corchorus accessions in their agro-morphological traits for exploitation in future breeding programmes that in turn can contribute to the improvement of this crop.     

Genetic structure and differentiation among grapevines (<Emphasis Type="Italic">Vitis vinifera</Emphasis>) accessions from Maghreb region

Three gene pools representative of Vitis vinifera L. subsp. vinifera (=subsp. sativa Beger) growing in the Maghreb regions (North Africa) from Tunisia (44), Algeria (31) and Morocco (18) and 16 wild grape accessions (Vitis vinifera L. subsp. sylvestris (Gmelin) Beger) from Tunisia were analysed for genetic diversity and differentiation at twenty nuclear microsatellites markers distributed throughout the 19 grape chromosomes. 203 alleles with a mean number of 10.15 alleles per locus were observed in a total of 109 accessions. Genetic diversities were high in all populations with values ranging from 0.6775 (Moroccan cultivars) to 0.7254 (Tunisian cultivars). F _st pairwise values between cultivated grapevine populations were low but found to be significantly different from zero. High F _st pairwise values were shown between wild and cultivated compartments. Two parent offspring relationships, two synonyms and two clones of the same cultivar were detected. The rate of gene flow caused by vegetative dissemination of cultivated grapevine plants was not sufficient to genetically homogenise the pools of cultivars grown in different regions. The Neighbour Joining cluster analysis showed a clear separation according to geographical origins for the cultivated grapevines gene pools and revealed a high dissimilarity between cultivated and wild grapevine. However, three cultivars (Plant d’Ouchtata 1, Plant de Tabarka 3 and Plant d’Ouchtata 3) are very close to wild accessions and may result from a hybridisation between cultivated and wild accessions. The high level of differentiation between cultivated and wild accessions indicates that the cultivated accessions do not derive directly from local wild populations but could mostly correspond to imported materials introduced from others regions during historical times or derived from crossing between them.