| 1. |
- Desta, Zeratsion Abera, et al.
(författare)
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Genomic selection: genome-wide prediction in plant improvement
- 2014
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Ingår i: Trends in Plant Science. - : Elsevier BV. - 1360-1385 .- 1878-4372. ; 19, s. 592–601-
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Forskningsöversikt (refereegranskat)abstract
- Association analysis is used to measure relations between markers and quantitative trait loci (QTL). Their estimation ignores genes with small effects that trigger underpinning quantitative traits. By contrast, genomewide selection estimates marker effects across the whole genome on the target population based on a prediction model developed in the training population (TP). Whole-genome prediction models estimate all marker effects in all loci and capture small QTL effects. Here, we review several genomic selection (GS) models with respect to both the prediction accuracy and genetic gain from selection. Phenotypic selection or markerassisted breeding protocols can be replaced by selection, based on whole-genome predictions in which phenotyping updates the model to build up the prediction accuracy.
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| 2. |
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| 3. |
- Hegay, Sergay, et al.
(författare)
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Comparing genetic diversity and population structure of common beans grown in Kyrgyzstan using microsatellites
- 2012
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Ingår i: Scientific Journal of Crop Science. - 2322-1690. ; 1, s. 63-75
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Tidskriftsartikel (refereegranskat)abstract
- Common bean (Phaseolus vulgaris L.) is an important export crop in Kyrgyzstan. The aim of this study was to assess the extent of genetic diversity, determine the population structure, and relate to the main gene pools grown in Kyrgyzstan. Twenty-eight common bean accessions (including five Kyrgyz cultivars, and main references from the Mesoamerica and South America) were evaluated with microsatellites. Nine polymorphic microsatellites were used to estimate genetic diversity and heterozygosity. The number of alleles per microsatellite locus ranged from 2 to 4 and there were a total of 24 alleles. The observed heterozygosity of each accession over all loci ranged from 0 to 0.11 (with an average of 0.01), while the expected average heterozygosity was 0.05, which could reflect the self-pollinating breeding behavior of common beans. The analysis of molecular variance further revealed that 94.71% of the total variation was accounted by differences among accessions (Fst =0.947; p<0.001). Cluster analysis grouped accessions in two gene pools: 16 belong to the Andean and 12 to the Mesoamerican gene pool. The microsatellites separated accessions in Mesoamerican gene pool from Durango and Jalisco races, which were grouped together. We also observed that the most divergent accessions were the Kyrgyz cultivars, which may be related to the Mesoamerican races. Andean accessions were less diverse than Mesoamerican accessions in this study. This research confirms the ability of microsatellites to differentiate common bean accessions, even using a small sample size, and to be able to assign modern cultivars to their gene pools or races.
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| 4. |
- Hegay, Sergay, et al.
(författare)
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Genetic diversity analysis in Phaseolus vulgaris L. using morphological traits
- 2014
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Ingår i: Genetic Resources and Crop Evolution. - : Springer Science and Business Media LLC. - 0925-9864 .- 1573-5109. ; 61, s. 555-566
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 5. |
- Hegay, Sergay, et al.
(författare)
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Introducing host-plant resistance to anthracnose in Kyrgyz common bean through inoculation-based and marker-aided selection
- 2014
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Ingår i: Plant Breeding. - : Wiley. - 0179-9541 .- 1439-0523. ; 133, s. 86-91
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Tidskriftsartikel (refereegranskat)abstract
- Common bean (Phaseolus vulgaris L.) is one of the most important legume crops for human consumption. However, its grain yield can be reduced by up to 90% by the seedborne disease, anthracnose. Fungicide treatment is costly and time-consuming. The introduction of host plant resistance against this disease appears, therefore, to be crucial for enhancing the productivity of this crop in Kyrgyzstan. The use of DNA-based markers in backcrossing programmes may help speed up the breeding for resistance. In this study, we used a combination of inoculation tests and a DNA marker (SCAreoli marker) to track the transfer of host-plant resistance (Co-2 gene) from two donor cultivars, Vaillant' and Flagrano', to susceptible Kyrgyz cultivars Ryabaya', Kytayanka' and Lopatka', which are widely grown in the country. The segregating offspring were evaluated to test the reliability of the SCAreoli marker as selection aid for host-plant resistance to anthracnose. Our study showed that a co-dominant DNA marker can successfully be used in backcross breeding to distinguish segregating material in different market classes of common bean.
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| 6. |
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| 7. |
- Motlhaodi, Tiny, et al.
(författare)
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Genetic diversity in ex-situ conserved sorghum accessions of Botswana as estimated by microsatellite markers
- 2014
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Ingår i: Australian Journal Of Crop Science. - 1835-2693 .- 1835-2707. ; 8, s. 35-43
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Tidskriftsartikel (refereegranskat)abstract
- Simple sequence repeat (SSR) markers were used to characterize genetic diversity in 30 sorghum [Sorghum bicolor (L.) Moench] accessions conserved in the national gene bank of Botswana. This collection represents the three sorghum-growing agro-ecological zones in the country. Ten microsatellite primer pairs were used, and these generated a total of 53 alleles with three to seventeen alleles per locus across the 30 accessions. A high level of genetic variation was observed among the accessions (70% of the variation), and 30% of the total genetic variation was observed within accessions. The analysis of molecular variance on sorghum accessions grouped based on agro-ecological region, ethnicity, and sorghum race revealed a non-significant variation, indicating that the alleles are distributed all over the country. Cluster analysis also did not group the accessions according to agro-ecological region, race or ethnicity. The results of this study have indicated that substantial genetic diversity exists among sorghum accessions conserved in Botswana, but that agro-ecological region, ethnicity and race did not influence the distribution of this diversity
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| 8. |
- Muzila, Mbaki, et al.
(författare)
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Assessment of diversity in Harpagophytum with RAPD and ISSR markers provides evidence of introgression
- 2014
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Ingår i: Hereditas. - : Springer Science and Business Media LLC. - 0018-0661 .- 1601-5223. ; 151, s. 91-101
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Tidskriftsartikel (refereegranskat)abstract
- The genus Harpagophytumhas two species: H. procumben swhich is an important medicinal plant in southern Africa, and H. zeyheri. Genetic diversity in 96 samples, obtained by germinating seeds collected from Botswana, was assessed using six inter-simple sequence repeat (ISSR) and 10 random amplified polymorphic DNA (RAPD) primers. These DNA markers yielded a total of 138 polymorphic bands. Polymorphism information content (PIC) ranged from 0.06 to 0.39 for ISSR primers, and from 0.09 to 0.43 for RAPD primers. Jaccard's similarity coefficients were highest when seedlings derived from the same fruit capsule were compared, while seedlings from different fruits on the same plant had intermediate values. The lowest values were recorded among seedlings from different plants. These results were consistent with an outcrossing breeding system in Harpagophytum. Analysis of molecular variance revealed significant differentiation (P < 0.01) between taxonomic units within Harpagophytum. About 39% of the variability occurred between the two species, H. procumbens and H. zeyheri. Plants with an intermediate morphology, i.e. putative hybrids (PH), showed 21% differentiation when compared with H. procumbens ssp. procumbens (PP), and 19% when compared with H. procumbens ssp. transvaalense (PT) or with H. zeyheri (ZZ). In addition, a deviating variant of PT was identified, here termed ‘procumbens new variety’ (PN). PN showed only 9% differentiation when compared with PT, 22% when compared with PP or with PH, and 41% when compared with ZZ. Considerable differentiation between the two Harpagophytum species was revealed also by a cluster analysis. Introgression was, however, suggested by the intermediate position of the putative hybrid plants in a principal component analysis while inter-specific gene flow was shown by a Bayesian genetic structure analysis.
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| 9. |
- Ortiz Rios, Rodomiro Octavio
(författare)
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Additive relationships and parent-offspring regression in Musa germplasm with intergeneration genome size polymorphism
- 2012
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Ingår i: Scientia Horticulturae. - : Elsevier BV. - 0304-4238 .- 1879-1018. ; 136, s. 69-74
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Tidskriftsartikel (refereegranskat)abstract
- Parent-offspring regression has often been used for the estimation of breeding value and narrow-sense heritability in experimental populations. particularly for diploid species with regular disomic inheritance. With polysomic inheritance, estimates of heritability based on parent-offspring regression are expected to be systematically biased, particularly when intra- and inter-generation ploidy polymorphisms occur as a result of unusual megasporogenesis. Measuring the discrepancy between true and estimated heritability has important theoretical and practical implications for the genetic improvement of plantain and bananas. In this regard, formulas were developed to describe the relationships between parental and filial generations with different ploidy states and this information was used to estimate heritability for several traits of plantains and bananas. This approach may be extended to other polysomic species with similar meiotic behaviour and ploidy polymorphism. (c) 2012 Elsevier B.V. All rights reserved.
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| 10. |
- Ortiz Rios, Rodomiro Octavio
(författare)
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Advances in Transgenic Vegetable and Fruit Breeding
- 2014
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Ingår i: Agricultural Sciences. - : Scientific Research Publishing, Inc.. - 2156-8553 .- 2156-8561. ; 5, s. 1448-1467
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Tidskriftsartikel (refereegranskat)abstract
- Vegetables and fruits are grown worldwide and play an important role in human diets because they provide vitamins, minerals, dietary fiber, and phytochemicals. Vegetables and fruits are also associated with improvement of gastrointestinal health, good vision, and reduced risk of heart disease, stroke, chronic diseases such as diabetes, and some forms of cancer. Vegetable and fruit production suffers from many biotic stresses caused by pathogens, pests, and weeds and requires high amounts of plant protection products per hectare. United States vegetables farmers are benefiting from growing transgenic squash cultivars resistant to Zucchini yellow mosaic virus , Watermelon mosaic virus , and Cucumber mosaic virus , which were deregulated and commercialized since 1996. Bt- sweet corn has also proven effective for control of some lepidopteran species and continues to be accepted in the fresh market in the USA, and Bt- fresh-market sweet corn hybrids are released almost every year. Likewise, transgenic Bt- eggplant bred to reduce pesticide use is now grown by farmers in Bangladesh. Transgenic papaya cultivars carrying the coat-protein gene provide effective protection against Papaya ring spot virus elsewhere. The transgenic “Honey Sweet” plum cultivar provides an interesting germplasm source for Plum pox virus control. Enhanced host plant resistance to Xanthomonas campestris pv. musacearum , which causes the devastating banana Xanthomonas wilt in the Great Lakes Region of Africa, was achieved by plant genetic engineering. There are other vegetable and fruit crops in the pipeline that have been genetically modified to enhance their host plant resistance to insects and plant pathogens, to show herbicide tolerance, and to improve features such as slow ripening that extends the shelf-life of the produce. Consumers could benefit further from eating more nutritious transgenic vegetables and fruits. Transgenic plant breeding therefore provides genetically enhanced seed embedded technology that contributes to integrated pest management in horticulture by reducing pesticide sprays as well as improving food safety by minimizing pesticide residues. Furthermore, herbicide-tolerant transgenic crops can help reducing plough in fields, thereby saving fuel because of less tractor use, which also protects the structure of the soil by reducing its erosion. Transgenic vegetable and fruit crops could make important contributions to sustainable vegetable production and for more nutritious and healthy food. Countries vary, however, in their market standards of acceptance of transgenic crops. Biotechnology products will be successful if clear advantages and safety are demonstrated to both growers and consumers
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