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1.
Genetic diversity, population structure and genome-wide linkage disequilibrium (LD) was estimated in Nordic spring barley (Hordeum vulgare L. subsp. vulgare) by genotyping 180 breeding lines with 48 SSR markers and 7842 high-confidence SNPs using the Illumina Infinium 9K assay. In total 6208 SNPs were polymorphic and selected for further statistical analysis. A Mantel test revealed a strong positive correlation with a Pearson’s correlation coefficient (r) of 0.86, between the estimates of genetic distances based on SSR and SNP data. Population structure analysis identified two groups with a clear ancestry and one group with an admixed ancestry. The groups were primarily separated based on row-type and geographical origin. Average LD for the whole population decayed below a critical level of r2 = 0.20 within a range of 0–4 cM. To avoid confounding effects of the strong population structure, LD decay for the different groups was analysed separately and ranged from 0 to 12 cM. A slower LD decay was found within the two-rowed lines compared to the six-rowed lines and the two-rowed lines originating from the northern part, which could be the result of strong selection for malting quality and yield in the southern part. No large difference in genetic diversity was observed between population sub-groups, but differences at certain chromosomal regions were evident.  相似文献   

2.
A barley core collection can be studied extensively and the derived information can be used to identify loci/genes for the genetic improvement of quantitative and qualitative traits. To assess genetic diversity, allelic variation and population structure of Egyptian barley, 134 barley genotypes collected from a different region along with 19 cultivated genotypes obtained from of the Egyptian Agricultural Research Center. All genotypes were analyzed with 261 polymorphic SSR and SNP alleles. The mean number of alleles per locus was 4 and PIC was 0.49, while the level of genetic diversity was 0.55 ranging from 0.03 to 0.82. The genotypes were assigned to three subpopulations that were consistent with their origins. The genetic variation within population was higher (51%) than among population at the molecular levels (FST =?0.491 when P?<?0.10). The level of polymorphic variation was highest in subpopulations-II, due to collected from different regions with different ear-types thus, expected to contain more diversity than local genotypes in subpopulations-I and subpopulations-III. The structured study found that the 153 barley genotypes are in harmony with clustering approaches using the SSR and SNP genotypic data in a neighbor-joining tree and principal components analysis, which identified three subpopulations. These results demonstrated genetic diversity among the Egyptian barley genotypes can be applied to suggest approaches, such as association analysis, classical mapping population development, and parental line selection in breeding programs. Therefore, it is necessary to use the exotic genotypes as the genetic resources for developing new barley cultivars in Egypt.  相似文献   

3.
Wild species of safflower, Carthamus oxyacanthus Bieb., is highly crossable with cultivated species, C. tinctorius L. and could be directly exploited in broadening safflower gene pool and improving the crop for biotic and abiotic stress environments. In this study, genetic diversity among accessions of C. oxyacanthus and their relationships with cultivated safflower were evaluated using agro-morphological traits and polymorphic inter-simple sequence repeats (ISSR) markers. Significant variation was observed among accessions particularly for seeds per capitulum, seed yield per plant, harvest index and capitula per plant. Cluster analysis based on agro-morphological traits classified the wild accessions in two groups according to their geographical regions, and separated them from the cultivated genotypes. ISSR marker also revealed a high genetic variation among the accessions, and cluster analysis based on this marker divided genotypes into four groups, with cultivated ones in a separate clade. Genetic variation observed among the wild safflower germplasm at the DNA level was higher than the agro-morphological traits, indicating that ISSR is an effective marker system for detecting diversity among safflower genotypes and their genetic relationships. Accessions of C. oxyacanthus with high genetic relationship to cultivated species could be used for interspecific hybridization in breeding programs of safflower.  相似文献   

4.
Cultivated sorghum [Sorghum bicolor (L.) Moench] is an important food security crop in the semi-arid regions of the world including Asia and Africa. Its genetic diversity is contained mostly in traditional varieties and modern cultivars used by farmers. In this study, agro-morphological traits and molecular markers were used to assess genetic diversity in 22 accessions of cultivated sorghum from five countries (Botswana, Namibia, Swaziland, Zambia and Zimbabwe) in the Southern African Development Community (SADC) region. The study revealed a significant variation among 22 accessions in both qualitative and quantitative morphological traits, indicating the accessions’ promising potential as breeding material. For molecular analysis, 11 microsatellite primer-pairs were used, and generated a total of 70 alleles across 20 accessions. Analysis of molecular variance revealed a high level of genetic variation; 67 % among the accessions and 10 % among the five countries. The patterns of genetic diversity and the relationships observed in this study should provide insights for genetic resource conservation and utilization of sorghum germplasm in the SADC region.  相似文献   

5.
Cowpea cultivation in many countries around the Mediterranean Basin depends on a number of locally adapted populations conserved on-farm at a small scale, rather than on the use of modern varieties. Documentation, characterization and exploitation of traditional local populations could contribute to their conservation and utilization as sources of desirable characteristics. Therefore, a study was conducted to (a) characterize, (b) assess diversity and (c) classify 23 on-farm conserved local cowpea populations based on 32 agro-morphological traits. Investigations on diversity of characteristics related to seed yield, mineral and seed crude protein content as well as on correlations among them were carried out. A relatively high phenotypic diversity was observed. In particular, a high level of within population diversity was found (\( \bar{H}s \) = 0.34) exceeding that among populations’ diversity (Gst = 0.27). Principal component analysis classified the majority of local populations into two groups (mainly according to populations’ seed coat color and eye color), further divided into six subgroups regardless of the populations’ geographical origin. Significant differences were also observed among the populations studied for potassium and calcium, as well as for their seed crude protein content which ranged from 22.14 to 28.37 %. The results show appreciable levels of intra- and inter-phenotypic diversity in on-farm conserved cowpea populations, which indicates the existence of a valuable gene pool for future exploitation in breeding programs.  相似文献   

6.
Lima bean is a species cultivated broadly in the Americas and has been cultivated in the Caribbean for at least 500 years. In order to determine the genetic structure and diversity of Lima bean from the Caribbean, 50 landraces from Haiti, the Dominican Republic and Puerto Rico were collected and analyzed using 24 SSR markers. All landraces in this Caribbean collection were found to be of Middle-American descent. The genetic diversity (HE) was highest in the landraces from Puerto Rico and lowest in Haitian landraces. The observed proportion of heterozygotes (HO) was higher in the Haitian landraces and lowest in Puerto Rican landraces. Unweighted pair-group method with arithmetic averaging analysis showed that the landraces clustered into 3 clusters with all Haitian landraces grouping in one cluster. We also assessed the agro-morphological characteristics of the collection as well as the content of cyanogenic glucoside, linamarin, in leaves and dry seeds. Lima bean, which is a model crop for indirect plant defenses against herbivory, also possess linamarin as a source of direct plant defense. Upon tissue damage, linamarin is converted to toxic hydrogen cyanide. In our collection 44.6 % of the landraces had average seed HCN content ≤200 ppm which is the permitted level for Lima bean seed in the US. Our results also identified the landraces in this collection which have high linamarin levels in the leaves while having low levels in the seeds. Such landraces have the desirable combination of traits and will be the focus of our future plans for agronomic trait improvement though breeding.  相似文献   

7.
Wild barley, Hordeum vulgare L. ssp. spontaneum (C. Koch) Thell., is the progenitor of cultivated barley. Almost unanimously the center of diversity is considered to be in the Fertile Crescent of the Near East, where wild barley grows under a wide range of environmental and climatic conditions. Jordanian wild barley is expected to harbor genes useful for the improvement of cultivated barley, particularly those associated with tolerance to drought. This study evaluated 103 wild barley accessions collected from different areas of Jordan along with 29 cultivated barley genotypes for several morphological and agronomical traits. The Hordeum vulgare ssp. spontaneum C. Koch accessions were grouped into six populations according to the longitude, latitude, altitude, and rainfall zone of the collection site, and the cultivated barley in one population. The evaluation was conducted during the 2004–2005 growing season under field conditions in three locations in Jordan; namely, Khanasri, Ramtha, and Maru with 123.0, 222.9, and 429.2 mm annual rainfall, respectively. We used an unreplicated design with two systematic checks (the cultivars Rum and Mu’ta) each repeated 15 times. The results showed the existence of high variability among the Hordeum vulgare ssp. spontaneum C. Koch accessions for most of the traits, especially for plant height, tiller number, days to heading, days to anthesis, peduncle length, and peduncle extrusion. Plant height, earliness, peduncle length, and peduncle extrusion were found to be adaptive traits under drought conditions and several superior genotypes for each trait were identified. Genetic variation within population was much higher than between populations. Clustering of populations was according to their ecological geographical pattern.  相似文献   

8.
Variation in response to climatic and edaphic factors has resulted in the geographic differentiation and specific adaptation of lentil germplasm to its environment. The germination of lentil seeds can be affected by waterlogging caused by relay sowing into standing rice crops. Consequently, there is a demand for waterlogging-adapted lentil genotypes, particularly at germination. This experimentation investigated the effects of waterlogging at germination on a germplasm collection. Firstly, two contrasting genotypes, ATC 70876 and Nugget, were waterlogged for six durations (0, 3, 6, 9, 14 and 21 days) in a pot soil system in the glasshouse. Six days of waterlogging was the duration for germination where genotypes showed the largest contrast in germination rate; therefore, this duration was applied to a larger number (127) of genotypes from 11 countries in a screening trial. Finally, all 127 genotypes were grown in pots in the open to phenotype morphological traits (seed size, above-ground biomass, time to flower and maturity). There was significant variation among genotypes, and those originating from Bangladesh had the highest germination at 21.2 %. The heritability of germination on waterlogged soil among genotypes was intermediate at H2 = 44.8 %. Correlations between morphological and physiological traits showed that the capability of seeds to germinate on waterlogged soil was negatively correlated to time to maturity (r = ?0.643). It was concluded that genotypes from Bangladesh are adapted to waterlogging at germination. With an intermediate heritability for germination under waterlogging conditions, selection for relay sowing through waterlogging tolerance at germination is practicable.  相似文献   

9.
The genebank at ICRISAT conserves the largest collection of 23,092 pearl millet germplasm accessions originating in 52 countries. A total of 15,979 landraces originating in 34 countries and having geographic coordinates of the collection sites were selected to investigate the geographical distribution of pearl millet traits and diversity in the collection. Results revealed adaptation of pearl millet to latitudes ranging between 33.00°S and 36.91°N. Landraces with early flowering (33–40 days) were predominant in Pakistan, Ghana, Togo and India; with very late flowering (121–159 days) in Sierra Leone and the Central African Republic; with short plant height (80–100 cm) in India, Zambia and Sudan; with tallness (401–490 cm) in Chad, Burkina Faso, Nigeria and the Central African Republic; with high tillering (11–35) in India and Yemen; with high panicle exsertion (11–29 cm) in Ghana, Chad, India and Yemen; with long panicles (75–135 cm) in Nigeria and Niger; with thick panicles (41–58 mm) in Namibia, Togo and Zimbabwe and those with large seeds (16–19 g 1000 seeds?1) were predominant in Togo, Benin, Ghana and Burkina Faso. Collections from Ghana for flowering (36–150 days), Burkina Faso for plant height (80–490), India and Yemen for total (1–35) and productive (1–19) tillers per plant, Niger for panicle exsertion (?45 to 21.0), panicle length (9–135 cm) and thickness (12–55 mm) and Zimbabwe for 1000 seed weight (3.5–19.3 g), were found as important sources for trait diversity. Launching collection missions for trait-specific germplasm is suggested to enrich the world collection of pearl millet at ICRISAT genebank for diversity.  相似文献   

10.
Barley (Hordeum vulgare L.) is one of the economically important cereal crops grown in the highlands of the Kyrgyz Republic. In marginal agricultural areas of the country barley is considered as irreplaceable and very suitable fodder crop for livestock. In this study the genetic diversity of currently grown farmers’ spring barley material from Naryn and Issik-Kul provinces is described. In order to capture maximum diversity present in farmer field’s different morphological types were collected. The 22 spring barley accessions collected in 2008 were described morphologically and analysed using fourteen simple sequences repeat (SSR) markers. Most material was two-rowed barley, 78 %, whereas six-rowed barley was only 22 %. The spike colours present were light yellow, dark yellow, brown and violet. The material varied also for such characters as length of spike and number of kernels per spike. For the SSR loci 129 alleles were detected with an average of 9.3 alleles per locus and a genetic diversity with an average of h = 0.721 per locus. Based on analysis of molecular variance the 71.3 % of genetic diversity accounted for within accession variation, whereas 27.4 % for among accession variation. The variation between provinces was not significantly different. A group of two-rowed barley was identified that was more closely related to six-rowed barley than to the rest of the two-rowed barley material. Two-rowed material currently grown in Kyrgyzstan is more diverse than six-rowed barley (h = 0.65, A = 8.8 vs. h = 0.59, A = 3.1). From this study we could conclude that the materials nowadays grown by farmers are mixtures. Since there are no geographic differentiation between these mixtures suggests that materials is frequently inter-exchanged between farmers and are most probably not landrace material. The question concerning the origin of these mixtures remains unsolved and further investigation will be carried out to identify sources of variation in farmers’ field.  相似文献   

11.
Common bean (Phaseolus vulgaris) is an important export crop in Kyrgyzstan since the end of the twentieth century. Genetic diversity analysis of common bean populations is useful for breeding programs, as it helps to select genetic material to be used for further crossing. Twenty-seven common bean accessions were analyzed using 13 qualitative morphological traits. In some cases, obtained morphological data were combined with previously published results based on microsatellite markers. The similarity matrices generated from the molecular and morphological data were significantly correlated (r = 0.49, P < 0.01). Cluster analyses based on Dice’s similarity coefficient were constructed based on morphological data and the combined data set of morphology and microsatellite, and both grouped the 27 accessions according to their origin: 15 belonged to the Andean and 12 to the Mesoamerican gene pool. On average, the Andean accessions were less diverse than the Mesoamerican accessions. The average diversity based on the Shannon diversity index for the 13 qualitative morphological traits was 0.05. Overall, this study revealed that qualitative morphological markers are efficient in assigning modern cultivars to their gene pools of origin.  相似文献   

12.
This work studied the combined use of gliadins and SSRs to analyse inter- and intra-accession variability of the Spanish collection of cultivated einkorn (Triticum monococcum L. ssp. monococcum) maintained at the CRF-INIA. In general, gliadin loci presented higher discrimination power than SSRs, reflecting the high variability of the gliadins. The loci on chromosome 6A were the most polymorphic with similar PIC values for both marker systems, showing that these markers are very useful for genetic variability studies in wheat. The gliadin results indicated that the Spanish einkorn collection possessed high genetic diversity, being the differentiation large between varieties and small within them. Some associations between gliadin alleles and geographical and agro-morphological data were found. Agro-morphological relations were also observed in the clusters of the SSRs dendrogram. A high concordance was found between gliadins and SSRs for genotype identification. In addition, both systems provide complementary information to resolve the different cases of intra-accession variability not detected at the agro-morphological level, and to identify separately all the genotypes analysed. The combined use of both genetic markers is an excellent tool for genetic resource evaluation in addition to agro-morphological evaluation.  相似文献   

13.
Bambara groundnut an indigenous crop of African origin is drought tolerant and the third most important leguminous crop in Ghana and Sub-Saharan Africa. In order to assess the level of genetic diversity within a small collection of Ghanaian landraces, molecular analysis was performed using microsatellite markers alongside characterization of morphological features. Genetic distance based on Jaccard’s similarity coefficient from the SSR marker analysis ranged from 0.48 to 0.9 among the landraces. 80 individual genotypes were clustered into 17 units with substantial levels of inter- and intra-landrace polymorphism. The analyses of variance from the morphological characterization for all quantitative traits were statistically significant (p < 0.05) except for terminal leaflet width. The first 4 principal components accounted for 41.97, 20.15, 13.39 and 9.81 % respectively of the morphological variations among the landraces. Qualitative traits however accounted for less of these variations. The results of the present study support the availability of high level of polymorphism within the collection of bambara groundnut analysed. This report is useful to crop improvement and germplasm conservation of bambara groundnut in Ghana.  相似文献   

14.
In Ethiopia, barley is generally grown in two different planting seasons per year: during the long rainy season (Meher) and the short rainy season (Belg). The aim of the present study was to assess for the first time the role of this ‘two-season system’ on the structure of the genetic diversity of the Ethiopian barley landraces. We characterised 3,170 individual genotypes from 106 landrace populations using eight morphological spike traits. The diversity within population was higher in the season where barley is more important (Belg), and in general, where its cultivation is in larger plots because of weaker ‘competition’ with others crops. This indicates that barley diversity has a complex relationship with variations in the surrounding agro-ecosystem. Overall, the divergence between the two seasons was quite small (3.4%), suggesting that seed flow does not occur independently across the years within the two seasons. This would affect the amount of mutations and historic recombination that have accumulated within these populations.  相似文献   

15.
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16.
Patterns of geographical diversity, and the relationship between agro-morphological traits and fatty acid composition were assessed for 193 safflower (Carthamus tinctorius) accessions representing forty countries. Accessions were assigned to eight groups based on geographical proximity. Cluster and Principal Component analyses were performed to assess patterns of diversity among the accessions and to select the most distant accessions from each of eight groups for analysis of randomly amplified polymorphic DNA (RAPD) markers. There was a large amount of diversity for agro-morphological traits, fatty acid composition, and RAPD markers. Most correlations among different traits were rather low. Plant height showed a positive correlation with days to flowering (r = 0.63**). Palmitic acid was positively correlated with stearic acid and oleic acid values, and negatively correlated with linoleic acid (P < 0.01). Oleic acid and linoleic acid showed a strong negative correlation (r = −0.89**). The first three principal components together explained 59% of the variation, however, neither principal component analysis (PCA) nor marker analysis revealed a clear relationship between diversity pattern and geographical origin. Accessions from some geographical regions tended to group together, such as accessions from South Western Asia, Central Western Europe, and the Mediterranean region. The correlation between the morphological matrix and the genetic matrix based on RAPD markers was not significant (r = 0.027). Wide diversity in safflower germplasm indicates a considerable potential for improving this crop for both agronomic and quality traits.  相似文献   

17.
Black cumin (Nigella sativa L.) is one of the important medicinal plants that used in food and pharmaceutical industries. In the present study, 32 Iran endemic black cumin genotypes were evaluated through randomized complete block design with three replications in 2016 and 2017 growing seasons to determine the extent of genetic diversity and character associations for agro-morphological and phytochemical traits. Results showed the significant differences between genotypes for all traits studied. Clustering analysis using agro-morphological and phytochemical traits grouped genotypes into the two distinct groups. The values of percentage of essential oil and fatty oil content varied from 0.65 to 0.1.36% and 25.30% to 35.02% between genotypes, respectively. The highest seed yield and fatty oil yield obtained for Arak genotype. GC and GC/MS analyses of essential oil and fatty oil compositions of the Arak genotype revealed that p-cymene and linoleic acid were main components, respectively. Stepwise regression analysis revealed that shoot dry mass, days to ripening and seed length were the most important traits associated with seed yield, fatty oil yield and essential oil yield. Hence, these traits can be considered as important indicators for early selection for seed yield and quality in black cumin breeding programs.  相似文献   

18.
Diversity and structure of populations may differ substantially between morphological traits and molecular markers. Explanations of such discrepancies are crucial for further progress in breeding as well as for the maintenance of genetic resources. Our objective was to compare indices of among-cultivars differentiation for morphological traits (QST) and molecular markers (FST) in alfalfa (Medicago sativa), a legume forage species. Ten cultivars representing the Northern and Southern types commonly grown in Europe were investigated. For each cultivar, 40 genotypes were analysed with 16 SSR markers and four morphological traits measured in two locations and several cuts. QST values were in general high (0.02–0.39) compared to the differentiation observed with molecular markers (FST = 0.01), especially for growth habit, indicating that morphological traits were more efficient to structure the diversity than molecular markers. For morphological traits, a clear separation of Northern and Southern cultivars was observed, whereas for molecular markers, no clear structure was detected. Nevertheless, the grazing type cultivar Luzelle was separated from the rest of the cultivars for both morphological traits and molecular markers. Although pairwise differences between cultivars were significant for both morphological traits and molecular markers, the main part of the variation was found within cultivars. This large within-cultivar variation may be explained, besides the outcrossing reproductive mode and autotetraploid genetics, by the recent history of M. sativa domestication in Europe and the frequent seed exchanges. Selection for morphological traits (QST > FST) was achieved without modification of within-cultivar neutral diversity.  相似文献   

19.
Sweet potato (Ipomoea batatas [L.] Lam) is a versatile crop globally serving as food, feed and raw material for industries. Designed selection for higher yields and related traits is crucial to identify complementary sweet potato clones for breeding. The objective of this study was to determine phenotypic variation among diverse sweet potato collections with regard to yield, dry matter content (DMC) and sweet potato virus disease (SPVD) resistance and to identify suitable clones for breeding. A total of 144 sweet potato genotypes were evaluated at 2 sites in Tanzania using a 12?×?12 simple lattice design. Data collected included 10 quantitative and 17 qualitative agro-morphological traits and virus reaction. Results indicated differences among genotypes for most traits studied. The mean DMC was 36% with clones Zapallo and Ukerewe exhibiting the lowest and highest values of 29% and 45%, respectively. The mean storage root yield of clones was 5.1?t/ha with genotype Jewel expressing the highest yield of 11.3?t/ha. Genotypes Resisto and Mataya were early flowering at 40 and 50 days, respectively, while Ex-Mwanza and Kandoro did not flower at all. Fifty-eight per cent of the genotypes showed resistant reaction to SPVD, while 31% and 11% were moderately susceptible and susceptible to the disease, respectively. A positive correlation was observed for the number of roots and fresh root yield. Seven clones including Simama, Ukerewe, Mataya, Resisto, 03–03, Ex-Msimbi-1 and Gairo were selected for high storage root yield and related traits or SPVD resistance. The selected genotypes are recommended as potential parents for sweet potato breeding.  相似文献   

20.
A total of 106 potential duplicate cases involved 277 accessions were detected on the basis of passport data in the durum wheat collection maintained in the CRF-INIA. Similarity between accessions was measured by agro-morphological traits. The 90% of the agro-morphological duplication were verified with gliadin proteins, allowing identification of similar material with greater refinement than agro-morphological data. However, the results indicated not to decide for rationalisation only on the basis of molecular data.  相似文献   

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