| 1. |
- Andreasen, Katarina, et al.
(författare)
-
Genetic identity of putative Linnaean plants : Successful DNA amplification of Linnaeus's crab apple Malus baccata
- 2014
-
Ingår i: Taxon. - : Wiley. - 0040-0262 .- 1996-8175. ; 63:2, s. 408-416
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Advancements in molecular techniques enable us to extract DNA from historic herbarium specimens and facilitate genetic comparisons between herbarium material and living plant collections. These recent advances offer an exciting opportunity for identifying extant Linnaean plants by genetic comparisons of Linnaeus's own herbarium specimens with potentially remnant plants from his cultivations. DNA from the lectotype of Malus baccata (L.) Borkh. in the Linnaean Herbarium was successfully extracted and amplified for five of twelve loci of microsatellites. Results of genetic comparisons with M. baccata trees from Linnaeus's Hammarby, Sweden, show that the trees at Hammarby are closely related to each other, but not to the lectotype, which is closer to material from Russia. This suggests that Linnaeus received M. baccata from more than one source. Although not close to the lectotype and not represented by a specimen in the Linnaean Herbarium, the extant M. baccata at Hammarby may still represent Linnaean plants, that were grown by Linnaeus himself, or the descendants to such plants. Future studies on the almost 50 living, potential Linnaean plants may reveal an invaluable biological, scientific and cultural heritage from the era that saw the rise of systematic biology.
|
|
| 2. |
|
|
| 3. |
- Crespo, Leonardo, et al.
(författare)
-
A systematic review of rye (Secale cereale L.) as a source of resistance to pathogens and pests in wheat (Triticum aestivum L.)
- 2017
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 154, s. 1-9
-
Forskningsöversikt (refereegranskat)abstract
- Wheat is globally one of the most important crops. With the current human population growth rate, there is an increasing need to raise wheat productivity by means of plant breeding, along with development of more efficient and sustainable agricultural systems. Damage by pathogens and pests, in combination with adverse climate effects, need to be counteracted by incorporating new germplasm that makes wheat more resistant/tolerant to such stress factors. Rye has been used as a source for improved resistance to pathogens and pests in wheat during more than 50 years. With new devastating stem and yellow rust pathotypes invading wheat at large acreage globally, along with new biotypes of pest insects, there is renewed interest in using rye as a source of resistance. Currently the proportion of wheat cultivars with rye chromatin varies between countries, with examples of up to 34%. There is mainly one rye source, Petkus, that has been widely exploited and that has contributed considerably to raise yields and increase disease resistance in wheat. Successively, the multiple disease resistances conferred by this source has been overcome by new pathotypes of leaf rust, yellow rust, stem rust and powdery mildew. However, there are several other rye sources reported to make wheat more resistant to various biotic constraints when their rye chromatin has been transferred to wheat. There is also development of knowledge on how to produce new rye translocation, substitution and addition lines. Here we compile information that may facilitate decision making for wheat breeders aiming to transfer resistance to biotic constraints from rye to elite wheat germplasm.
|
|
| 4. |
|
|
| 5. |
- Crespo, Leonardo, et al.
(författare)
-
Mapping resistance to the bird cherry-oat aphid and the greenbug in wheat using sequence-based genotyping
- 2014
-
Ingår i: TAG Theoretical and Applied Genetics. - : Springer Science and Business Media LLC. - 0040-5752 .- 1432-2242. ; 127, s. 1963-1973
-
Tidskriftsartikel (refereegranskat)abstract
- Identification of novel resistance QTL against wheat aphids. First QTL-resistance report for R. padi in wheat and chromosome 2DL for S. graminum . These sources have potential use in wheat breeding.The aphids Rhopalosiphum padi and Schizaphis graminum are important pests of common wheat (Triticum aestivum L.). Characterization of the genetic bases of resistance sources is crucial to facilitate the development of resistant wheat cultivars to these insects. We examined 140 recombinant inbred lines (RILs) from the cross of Seri M82 wheat (susceptible) with the synthetic hexaploid wheat CWI76364 (resistant). RILs were phenotyped for R. padi antibiosis and tolerance traits. Phenotyping of S. graminum resistance was based on leaf chlorosis in a greenhouse screening and the number of S. graminum/tiller in the field. RILs were also scored for pubescence. Using a sequence-based genotyping method, we located genomic regions associated with these resistance traits. A quantitative trait locus (QTL) for R. padi antibiosis (QRp.slu.4BL) that explained 10.2 % of phenotypic variation was found in chromosome 4BL and located 14.6 cM apart from the pubescence locus. We found no association between plant pubescence and the resistance traits. We found two QTLs for R. padi tolerance (QRp.slu.5AL and QRp.slu.5BL) in chromosomes 5AL and 5BL, with an epistatic interaction between a locus in chromosome 3AL (EnQRp.slu.5AL) and QRp.slu.5AL. These genomic regions explained about 35 % of the phenotypic variation. We re-mapped a previously reported gene for S. graminum resistance (putatively Gba) in 7DL and found a novel QTL associated with the number of aphids/tiller (QGb.slu-2DL) in chromosome 2DL. This is the first report on the genetic mapping of R. padi resistance in wheat and the first report where chromosome 2DL is shown to be associated with S. graminum resistance.
|
|
| 6. |
- Edin, Eva, et al.
(författare)
-
Genetic diversity and occurrence of the F129L substitutions among isolates of Alternaria solani in south-eastern Sweden
- 2016
-
Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 153
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Early blight, caused by the fungus Alternaria solani, occurs on potato mainly in the south-eastern part of Sweden, but also in other parts of the country. The aim of this study was to investigate the genetic diversity of A. solani populations from different potato growing regions in south-eastern Sweden using AFLP marker analysis. In addition, the cultured isolates were examined for substitutions in the gene encoding cytochrome b, associated with loss of sensitivity against QoI fungicides.Results: Nei's gene diversity index for the Swedish populations of A. solani revealed a gene diversity of up to 0.20. Also genetic differentiation was observed among populations of A. solani from different locations in south-eastern Sweden. The mitochondrial genotype of the isolates of A. solani was determined and both known genotypes, GI (genotype 1) and GII (genotype 2), were found among the isolates. The occurrence of the F129L substitution associated with a loss of sensitivity to strobilurins was confirmed among the GII isolates. In vitro conidial germination tests verified that isolates containing the F129L substitution had reduced sensitivity to azoxystrobin and, at a lower extent, to pyraclostrobin.Conclusions: Genetic diversity was relatively high among isolates of A. solani in south-eastern part of Sweden. F129L substitutions, leading to reduced sensitivity to strobilurins, have been established in field populations, which may have implications for the future efficacy of QoI fungicides.
|
|
| 7. |
|
|
| 8. |
- Elsafy, Mohammed, et al.
(författare)
-
Elucidating the genetic diversity of farmer cultivars of female date palms (Phoenix dactylifera L.) from Sudan by microsatellite markers
- 2016
-
Ingår i: Genetic Resources and Crop Evolution. - : Springer Science and Business Media LLC. - 0925-9864 .- 1573-5109. ; 63, s. 975-986
-
Tidskriftsartikel (refereegranskat)abstract
- Genetic diversity in female date palms for a total of 89 tree samples, representing 18 cultivar groups, was investigated using 10 loci of microsatellite (SSR) primers. The microsatellites examined showed high polymorphism, a total of 126 for the 10 microsatellite loci, giving an average of 12.6. Low F-ST values were observed among different fruit classification groups of Sudanese date palms (soft, semi-soft and dry) suggesting that the observed high genetic variability is maintained locally within cultivars. Across all genetic parameters, in comparison among the cultivar groups, the Jaw group was consistently highly variable followed by Korsha, Gondela and Barakawi, respectively. Multivariate analysis of the 89 date palms showed some strong relationships with some mixed grouping, showing a tendency of relate fruit classification and related genotypes. Dry dates almost grouped together while the soft and semi-soft were mixed and somewhat related to genotypes. The effect of genotype was highly supported by the relationship of 14 cultivar groups, in which similar cultivars were associated regardless of the state to which they belong. Further detailed analyses of female date palm populations from different geographic locations represented by a minimum of five plants per cultivar is necessary to provide the basis for understanding of the date palm genomes, revealing the true extent of gene flow between farmer cultivars.
|
|
| 9. |
- Elsafy, Mohammed, et al.
(författare)
-
Phenotypic Diversity of Date Palm Cultivars (Phoenix dactylifera L.) from Sudan Estimated by Vegetative and Fruit Characteristics
- 2015
-
Ingår i: International Journal of Biodiversity. - : Hindawi Limited. - 2314-4149 .- 2314-4157.
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to apply some of the vegetative and fruit traits which are easily recognised to identify the variation and the diversity level of the most famous Sudanese date palm cultivars grown on farm in the northern region of Sudan. Sixteen phenotypic traits consisting of ten quantitative and six qualitative characteristics were used for describing the vegetative and fruit characteristics. The principal components analysis (PCA) and UPGMA clustering were used to analyse the data set. The results revealed high variability among the cultivars according to PCA. Fourteen out of the sixteen quantitative and qualitative traits investigated showed a strong discriminating factor suggesting their possible uses in the initiation of Sudanese date palm morphological descriptor list. UPGMA clustering exhibited strong relationship between some cultivars according to their fruit and vegetative characteristics similarity. Based on morphological traits, cultivars Wad-laggi (Lag) and Wad-khateeb (Kha) formed a distinct group suggesting their close relatedness. Similarly, the cultivars sharing the dry fruit texture such as Gondaila (Gon), Tamoda (Tam), Kolmah (Kol), and Barkawi (Bar) were grouped together according to their vegetative traits. Further investigations on Sudanese date palm using more phenotypic characteristics are recommended in order to shape and complete the set of the morphological descriptor list.
|
|
| 10. |
|
|
