| 31. |
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| 32. |
- Calleja-Rodriguez, Ainhoa
(författare)
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Quantitative Genetics and Genomic Selection of Scots pine
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The final objective of tree improvement programs is to increase the frequency of favourable alleles in a population, for the traits of interest within the breeding programs. To achieve this, it is crucial to decompose the phenotypic variance accurately into its genetic and environmental components in order to obtain a precise estimation of genetic parameters and to increase genetic gains. The overall aim of this thesis was to increase the accuracy of genetic parameter estimation by incorporating new quantitative genetics models to the analysis of multiple traits in multiple trials of Scots pine, and to develop a genomic selection protocol to accelerate genetic gain. Factor analysis was incorporated to multivariate multi-environment analyses and it allowed to evaluate up to 19 traits simultaneously. As a result, precise patterns of genotype-by-environment interactions (G E) were observed for tree vitality and height; moreover, it was possible to detect the main driver of the G E: differences in temperature sum among sites. Traditional quantitative trait loci (QTL) analysis of phenotypic data was compared with the detection of QTL with estimated breeding values (EBV) for the first time in a three generation pedigree and, as outcome, it was noticed that if a QTL was associated to a EBV and to a phenotypic trait, the proportion of variance explained by the QTLEBV was higher than the QTL-phenotype. Additionally, several QTL were detected across several ages, which may make them suitable as candidates for early selection. Genomic selection (GS) could aid to reduce the breeding cycle by shortening the periods of progeny field testing, and consequently increasing genetic gains per year. Genomic predictions, including additive and non-additive effects through different prediction models were compared with traditional pedigree-based models; it was seen an overestimation of genetic parameters for pedigree-based models, even larger when nonadditive effects could not be discerned from additive and residual effects. Prediction accuracies and abilities of the genomic models were sufficient to achieve higher selection efficiencies and responses per year varying between 50-90% by shortening 50% the breeding cycle. For the selection of the top 50 individuals, higher gains were estimated if non-additive effects are incorporated to the models (7 – 117%).
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| 33. |
- Dida, Mulatu Geleta, et al.
(författare)
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Genetic Diversity within a Global Panel of Durum Wheat (Triticum durum) Landraces and Modern Germplasm Reveals the History of Alleles Exchange
- 2017
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Durum wheat is the 10th most important crop in the world, and its use traces back to the origin of agriculture. Unfortunately, in the last century only part of the genetic diversity available for this species has been captured in modern varieties through breeding. Here, the population structure and genetic diversity shared among elites and landraces collected from 32 countries was investigated. A total of 370 entries were genotyped with Axiom 35K array to identify 8,173 segregating single nucleotide polymorphisms (SNPs). Of these, 500 were selected as highly informative with a PIC value above 0.32 and used to test population structure via DAPC, STRUCTURE, and neighbor joining tree. A total of 10 sub-populations could be identified, six constituted by modern germplasm and four by landraces of different geographical origin. Interestingly, genomic comparison among groups indicated that Middle East and Ethiopia had the lowest level of allelic diversity, while breeding programs and landraces collected outside these regions were the richest in rare alleles. Further, phylogenetic analysis among landraces indicated that Ethiopia might represent a second center of origin of durum wheat, rather than a second domestication site as previously believed. Together, the analyses carried here provide a global picture of the available genetic diversity for this crop and shall guide its targeted use by breeders.
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| 34. |
- Eriksson, Dennis, et al.
(författare)
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Editorial: Leeway to operate with plant genetic resources
- 2020
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Editorial on the Research Topic Leeway to Operate With Plant Genetic Resources Different legal frameworks are applicable to the use of genetic resources (GR). These can broadly be categorized into (1) access and benefit-sharing (ABS), (2) biosafety aspects related to the technologies for improving the genetic material, and (3) intellectual property (IP) systems including plant variety rights (PVR) and patents specific to the plant innovation sector. With scientific and technical progress in research and breeding, as well as expanding internationalization, legal frameworks have become increasingly complex in the past few decades. In this context, the Research Topic “Leeway to operate with plant genetic resources” addresses the latest and most pertinent legalissues related to the use of GR in plant research and breeding.The contributions are summarized here and put into the larger societal and legal context that modern-day plant geneticists are facing.
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| 35. |
- Eriksson, Dennis, et al.
(författare)
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Overview and Breeding Strategies of Table Potato Production in Sweden and the Fennoscandian Region
- 2016
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Ingår i: Potato Research. - : Springer Science and Business Media LLC. - 0014-3065 .- 1871-4528. ; 59, s. 279-294
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Tidskriftsartikel (refereegranskat)abstract
- Recent reductions in the public commitment to potato breeding in Sweden, Norway and Finland call for an evaluation of the current situation regarding the commercial basis for, and structure of, potato breeding in these countries. We here review the extent of cultivation, processing and consumption of table potato in Sweden, as well as provide an overview of the potato breeding tools and programmes in the three countries. We then discuss various strategies to provide long-term stability and increase the impact of public potato breeding, based on the similar overall conditions for potato cultivation across the Fennoscandian region. The conclusions are twofold; first, an increased long-term funding of the public potato breeding programmes is necessary to maintain a minimum level of material, and second, a coordination of the breeding activities in the Fennoscandian region would be of great benefit to all involved stakeholders and allow an enhancement of the current national breeding programmes. In addition, we propose a minimum first field year population size for potato breeding.
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| 36. |
- Ghasemkhani, Marjan
(författare)
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Genetic basis for resistance against fruit tree canker in apple
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Neonectria ditissima (formerly Neonectria galligena, anamorph Cylindrocarpon heteronema) is the causal agent of fruit tree canker which is regarded as a serious economic problem in horticulture. This fungus causes notable damage to apple trees and it is very important in some regions, especially North western Europe, where it can result in death of spur shoots and branches. Although it occurs in a wide range of temperatures, it is associated with wet weather and climate has an important effect on the geographic distribution. The fungus produces conidia and ascospores, both of which are dispersed and cause infection during prolonged periods of rainy weather. Also, spores produced on the infected wood can act as an infection source in the orchards. The fungus can therefore be introduced into new orchards with infected planting material from other orchards or tree nurseries. Chemical and mechanical control like spraying of fungicides, covering wounds with paint, and cutting out infected branches, do not prevent the occurrence of epidemics. Breeding cultivars with a high level of resistance towards canker would be of great help towards the avoidance of this disease. Apple cultivars show variable levels of partial resistance to the fungus, whereas complete resistance has not yet been reported and no major genes have been identified. Therefore, apple genotypes with comparatively high levels of genetically determined partial resistance should be identified for use in apple breeding.
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| 37. |
- Hammenhag, Cecilia, et al.
(författare)
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Novel Expressed Sequence Tag-Derived and Other Genomic Simple Sequence Repeat Markers Revealed Genetic Diversity in Ethiopian Finger Millet Landrace Populations and Cultivars
- 2021
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Ingår i: Frontiers in Plant Science. - : Frontiers Media SA. - 1664-462X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Finger millet (Eleusine coracana (L.) Geartn.) is a self-pollinating amphidiploid crop cultivated with minimal input for food and feed, as well as a source of income for small-scale farmers. To efficiently assess its genetic diversity for conservation and use in breeding programs, polymorphic DNA markers that represent its complex tetraploid genome have to be developed and used. In this study, 13 new expressed sequence tag-derived simple sequence repeat (EST-SSR) markers were developed based on publicly available finger millet ESTs. Using 10 polymorphic SSR markers (3 genomic and 7 novel EST-derived), the genetic diversity of 55 landrace accessions and 5 cultivars of finger millet representing its major growing areas in Ethiopia was assessed. In total, 26 alleles were detected across the 10 loci, and the average observed number of alleles per locus was 5.6. The polymorphic information content (PIC) of the loci ranged from 0.045 (Elco-48) to 0.71 (UGEP-66). The level of genetic diversity did not differ much between the accessions with the mean gene diversity estimates ranging only from 0.44 (accession 216054) to 0.68 (accession 237443). Similarly, a narrow range of variation was recorded at the level of regional states ranging from 0.54 (Oromia) to 0.59 (Amhara and Tigray). Interestingly, the average gene diversity of the landrace accessions (0.57) was similar to that of the cultivars (0.58). The analysis of molecular variance (AMOVA) revealed significant genetic variation both within and among accessions. The variation among the accessions accounted for 18.8% of the total variation (FST = 0.19; P < 0.001). Similarly, significant genetic variation was obtained among the geographic regions, accounting for 6.9% of the total variation (P < 0.001). The results of the cluster, principal coordinate, and population structure analyses suggest a poor correlation between the genetic makeups of finger millet landrace populations and their geographic regions of origin, which in turn suggests strong gene flow between populations within and across geographic regions. This study contributed novel EST-SSR markers for their various applications, and those that were monomorphic should be tested in more diverse finger millet genetic resources.
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| 38. |
- Hammenhag, Cecilia, et al.
(författare)
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QTL mapping for domestication-related characteristics in field cress (Lepidium campestre)—a novel oil crop for the Subarctic region
- 2020
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Ingår i: Genes. - : MDPI AG. - 2073-4425. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Domestication of a new crop requires identification and improvement of desirable characteristics Field cress (Lepidium campestre) is being domesticated as a new oilseed crop, particularly for northern temperate regions.. In the present study, an F-2 mapping population and its F-3 progenies were used to identify quantitative trait loci (QTLs) for plant height (PH), number of stems per plant (NS), stem growth orientation (SO), flowering habit (FH), earliness (ER), seed yield per plant (SY), pod shattering resistance (SHR), and perenniality (PE). A highly significant correlation (p < 0.001) was observed between several pairs of characteristics, including SY and ER (negative) or ER and PE (positive). The inclusive composite interval mapping approach was used for QTL mapping using 2330 single nucleotide polymorphism (SNP) markers mapped across the eight field cress linkage groups. Nine QTLs were identified with NS, PH, SO, and PE having 3, 3, 2, and 1 QTLs, explaining 21.3%, 29.5%, 3.8%, and 7.2% of the phenotypic variation, respectively. Candidate genes behind three of the QTLs and favorable marker alleles for different classes of each characteristic were identified. Following their validation through further study, the identified QTLs and associated favorable marker alleles can be used in marker-aided breeding to speed up the domestication of field cress.
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| 39. |
- Jin, Yunkai, et al.
(författare)
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New Energy Crops for Biofuel Production
- 2015
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Ingår i: Handbook of clean energy systems. - Chichester, UK : John Wiley & Sons, Ltd. - 9781118388587 ; , s. 49-62
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Bokkapitel (refereegranskat)
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| 40. |
- Karlsson, Milla, et al.
(författare)
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Möjliga tillämpningar av nya genomiska tekniker inom integrerat växtskydd
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det pågår en omställning av jord- och trädgårdsbruket, både med hänsyn till hållbar produktion och pågående klimatförändringar. Som en del av EUs arbete att utveckla lantbruket mot en mer hållbar produktion har kommissionen lagt fram ett förslag på minskning av växtskyddsmedel om minst 50 %, totalt sett inom EU, senast 2030. För Sveriges del innebär förslaget, enligt preliminära beräkningar, att vi behöver minska mängden växtskyddsmedel med 35-36 %. För att ersätta funktionen av denna mängd växtskyddsmedel behövs ett integrerat tillvägagångssätt som kräver tillgång till andra effektiva metoder för bekämpning av skadegörare på odlade växter.Under det senaste decenniet har nya genomiska tekniker inom växtförädlingen utvecklats, vilka möjliggör riktade förändringar i många grödors genom. Teknikerna innebär antingen att man introducerar enstaka förändringar i DNA-sekvensen (s.k. genomredigering), eller att man sätter in en längre DNA-sekvens från samma art eller en korsningsbar art i en gröda (s.k. cisgenes). Dessutom har kunskapen om växters försvarssystem framskridit avsevärt. Med den ökade kunskapen och de nya teknikerna ökar möjligheten att kombinera gener och öka variationen av de gener som gör grödorna resistenta mot olika växtsjukdomar. På så sätt kan förädlingen av sjukdomsresistenta sorter ske med betydligt bättre precision och på kortare tid än vad traditionella förädlingstekniker tillåter. Tidsaspekten kan ses som extra viktig i resistenssammanhang eftersom skadegörarpopulationerna ändras kontinuerligt. Potentialen att kombinera flera olika resistensmekanismer för att uppnå mer uthållig resistens samt möjligheten att lösa ett eller flera växtskyddsproblem i samma sort bör också noteras.Enligt nuvarande EU-lagstiftning regleras dock genomredigerade och cisgena grödor på samma sätt som traditionellt genetiskt modifierade organismer (GMO), en lagstiftning som i praktiken omöjliggör kommersiell odling inom EU. Detta trots att resultatet av de moderna teknikerna kan efterlikna vad som kan ske spontant i naturen (mutationer) eller via traditionella oreglerade förädlingsmetoder (t.ex. mutations-, eller korsningsförädling). I lagstiftningen tas det ej i beaktande att sjukdomsresistenta grödor kan bidra till en minskad användning av växtskyddsmedel.Idag är potatisodling ofta förknippad med en användning av stora mängder växtskyddsmedel mot potatisbladmögel. Samtidigt är det möjligt att göra potatissorterna helt resistenta mot potatisbladmögel med hjälp av cisgenes och ge dem en ökad motståndskraft med hjälp av genomredigering. Om det vore möjligt att odla potatis som förädlats med nya genomiska tekniker inom EU idag, visar denna rapport att det skulle vara möjligt att kraftigt minska användningen av växtskyddsmedel i potatisodlingen. Det skulle innebära en reducering av mängden växtskyddsmedel som används inom det svenska lantbruket och skulle även innebära besparingar runt 91 miljoner SEK per år för odlarna.Vete och annan spannmål är de grödor där flest totala hektardoser av fungicider appliceras, till en årlig kostnad av två miljarder SEK. För dessa grödor finns inget lika tydligt exempel på enskilda sjukdomar som så kraftigt kan minska fungicidanvändningen. Vi ser dock en tydlig framtida potential att minska antalet bekämpningar och därmed kostnaden för lantbruket med hjälp av nya genomiska tekniker inom sädesslagen.Möjligheten att öka växters egen resistens för att minska användningen av växtskyddsmedel finns redan idag även i flera andra grödor, och möjligheterna förväntas fortsatt växa i takt med att teknikutveckling och forskning fortgår. En förändrad lagstiftning runt nya genomiska tekniker skulle även öppna för applikationer inom områden där det idag inte finns någon effektiv metod att bekämpa växtskadegörare. Exempel på sådana skadegörare är många virussjukdomar och skador som orsakas av nematoder. Därför kan skördestabiliteten och konkurrenskraften förväntas öka i grödor där det idag finns skadegörare där effektiva bekämpningsmetoder saknas.Sammanfattningsvis ser vi nya genomiska tekniker för att förädla resistenta grödor som en viktig del i arbetet mot ett hållbart jordbruk och för att uppnå EU-kommissionens mål om att reducera användningen av växtskyddsmedel inom jord- och trädgårdsbruket.
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