Browsing by Subject "breeding"
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Item Accessions from University of Minnesota Fruit Breeding Program 1923-1950: Accessions N231 to N50174(1950) Horticultural Research CenterItem Accessions from University of Minnesota Fruit Breeding Program 1951-1972: Accessions N511 to N72111(1972) Horticultural Research CenterItem Apple Selections Discarded from the University of Minnesota Fruit Breeding Program between 1975-2013: Volume 2 Selections MN1723 to MN1759(2013) Horticultural Research CenterItem Apple Selections Discarded from the University of Minnesota Fruit Breeding Program between 1979-2013: Volume 3 Selections MN1760 to MN1799(2013) Horticultural Research CenterItem Apple Selections Discarded from the University of Minnesota Fruit Breeding Program between 1980-2015: Volume 1 Selections MN1478 to MN1722(2015) Horticultural Research CenterItem Apple Selections Discarded from the University of Minnesota Fruit Breeding Program between 1983-2015: Volume 4 Selections MN1800 to MN1848(2015) Horticultural Research CenterItem Apple Selections Discarded from the University of Minnesota Fruit Breeding Program between 1984-2013: Volume 5 Selections MN1812 to MN1900(2013) Horticultural Research CenterItem The Breeding Ecology of Boreal Chickadees in the Red Lake Wildlife Management Area in Northern Minnesota(2023-08) Snow, KaraWe examined the impacts of fragmentation on the breeding ecology of the Boreal Chickadee (Poecile hudsonicus) in the Red Lake WMA in Minnesota. Boreal Chickadees are listed as a Species in Greatest Conservation Need (SGCN), with declines attributed to habitat loss, degradation and fragmentation. We used linear mixed-effect models to examine the impacts of fragmentation on Boreal Chickadee food availability, nestling growth rates, body condition and provisioning rates. We modeled nest survival in relation to landscape, patch and nest site scale metrics of fragmentation using the program MCEstimate. We found evidence that fragmentation negatively impacts nest survival, nestling growth rates and food availability. Additionally, we elucidated the diet of nestling Boreal Chickadees by extracting DNA from fecal samples and using DNA metabarcoding techniques. We found that Boreal Chickadee nestlings are primarily being provisioned prey from the orders: Lepidoptera, Aranea and Diptera; and are likely actively selecting for Lepidoptera.Item Duplicate Pollination Records from University of Minnesota Fruit Breeding Program from 1913-1922(1922) Horticultural Research CenterItem Duplicate Pollination Records from University of Minnesota Fruit Breeding Program from 1923-1929(1929) Horticultural Research CenterItem Duplicate Pollination Records from University of Minnesota Fruit Breeding Program from 1930-1935(1935) Horticultural Research CenterItem Duplicate Pollination Records from University of Minnesota Fruit Breeding Program from 1936-1941(1941) Horticultural Research CenterItem Field trial of honey bee colonies bred for mechanisms of resistance against Varroa destructor(2007) Ibrahim, Abdullah; Reuter, Gary S.; Spivak, MarlaWe compared colonies selectively bred for both hygienic behavior and Suppression of Mite Reproduction (HYG/SMR) with colonies bred solely for hygienic behavior (HYG) and unselected control colonies. Colonies were evaluated for strength, brood viability, removal of freeze-killed brood, honey production, mite loads on adult bees and within worker brood, and mite reproductive success on worker brood for two years in two locations. By autumn in both years, the HYG/SMR colonies had significantly fewer mites on adult bees and in worker brood compared to the control colonies, and the HYG colonies had intermediate mite populations. Contrary to expectation, there were no differences among the lines in mite reproductive success. Further studies are required to determine if the genes and neural mechanisms that regulate the SMR trait are the same or different from those regulating hygienic behavior.Item Honey bee hygienic behavior and defense against Varroa jacobsoni(Springer, 1996) Spivak, MarlaHygienic and non-hygienic colonies from ’Starline’ stock of Apis mellifera were tested for their ability to remove pupae infested with Varroa mites. The hygienic and non-hygienic lines were selected and bred on the basis of their removal response to freeze-killed brood. A Jenter Box® was used to test whether they would remove experimentally infested pupae following methods of Boecking and Drescher (1992). In 1994, the hygienic colonies removed significantly more pupae infested with one mite per cell than the non-hygienic colonies. In 1995, there was no significant difference between the hygienic and non-hygienic colonies when one or two mites were introduced per pupa due to variation in response among hygienic colonies. There was no significant difference between the rate of removal of infested pupae from the Jenter Box and from natural wax comb by the hygienic colonies. The number of mites damaged by grooming ranged from 6.0 to 42.3% among all colonies. The reproductive success of the mites not removed from the cells by the bees was low in both hygienic and non-hygienic colonies.Item Integrating Genomics and Metabolomics to Inform Breeding for Powdery Mildew Resistance in Grapevine(2018-08) Teh, Soon LiTwo powdery mildew resistance loci have been identified using pedigree-connected F1 mapping families at the University of Minnesota grape breeding program. A consensus linkage map of the resistant parent (MN1264) was developed for genetic mapping. The resistance loci were mapped on chromosomes 2 and 15, with additive effects accounting for over 30% phenotypic variation. Marker haplotypes, hap+chr2 and hap+chr15, were constructed to trace the inheritance of resistance loci in grandparent-parent-progeny relationships. Both hap+chr2 and hap+chr15 in the resistant F1 progeny were inherited from parent MN1264, that originated from grandparent ‘Seyval blanc’. Additionally, two microsatellites markers (i.e., UDV-015b and VViv67) were identified to be associated with hap+chr15, and can be applied for marker-assisted selection. In a follow-up study to characterize metabolic changes attributed to hap+chr2 and hap+chr15, a metabolomic experiment was conducted on whole-plant propagated grapes in a time-course response to in vivo inoculation. The use of several multivariate analyses systematically identified 52 biomarkers that were associated with hap+chr2, and 12 biomarkers with hap+chr15. In a temporal assessment of biomarkers, the discriminating metabolic changes distinguishing resistant and susceptible individuals appeared to be occurring from 24 to 48 hours after inoculation.Item Misfits of wheat stem rust resistance-‐ Unusual solutions to a consistent problem(2016-12) Briggs, JordanRust fungi include some of the most economically damaging pathogens of wheat. They are notorious for their ability to quickly spread in susceptible host populations and greatly reduce grain yield potential and quality when managed improperly. Puccinia graminis f. sp. tritici (Pgt), the causal agent of wheat stem rust, can cause yield losses exceeding 50%. Stem rust is controlled in the U.S.A. using several methods including the introduction of genetic resistance, selection for earlier maturing varieties, removal of the alternate host Berberis vulgaris, and the application of fungicides. Subsequently, epidemics of stem rust causing greater than 10% yield losses have not been observed in the U.S.A. since the mid 1950’s. Together, removal of B. vulgaris from wheat growing regions and the introduction of genetic resistance have accounted for much of the control of stem rust. Genetic resistance remains the dominant method of controlling stem rust in regions where removing B. vulgaris is not applicable. In more recent years, races of Pgt have been identified that overcome most widely deployed resistance genes. In 1999 race TTKSK was identified in Uganda that overcame stem rust resistance gene Sr31. Following deployment of Sr24 in Kenya, further selection for virulence resulted in the identification of race TTKST, then TTTSK (Sr36 virulence), and more recently TTKTT and TTKTK (SrTmp virulence). Major resistance genes have continually proven to not provide a durable form of resistance to wheat stem rust. Some resistance genes however have proven the test of time and remain effective to date. These resistance genes include Sr2, Lr34, Lr46, and Lr67. Each gene functions in an additive, minor-effect, and in some cases recessive manner, atypical of standard major genes, and provides and/or enhances resistance to multiple diseases including stem rust, leaf rust, stripe rust, and powdery mildew. Additionally Lr34 and Lr67 do not have the NB-LRR protein domains consistent with major genes. Durable genetic resistance to stem rust may require sources of resistance that deviate from standard mechanisms. This dissertation describes such sources of resistance. SrTm4 is a major gene identified in Triticum monococcum that functions in a recessive manner, is broadly effective, and elicits a mesothetic (intermediate-effect) infection type. The adult plant resistance observed in ‘Morocho Blanco’ was found to have two underlying QTL, Qsr.cdl.2BS.2 and Qsr.cdl.6AS.1. These two loci comprise much of the adult plant resistance in ‘Morocho Blanco’ and exhibit interactions with environment or pathogen race. The Sr12 mutants created in this dissertation were made to characterize the disease reducing capabilities of Sr12: a recessive, race specific major gene that co-locates with adult plant resistance to Sr12 virulent races. Lastly, this dissertation also describes the identification of putative susceptibility genes for rust pathogens in barley, maize, soybean, and Brachypodium distachyon. The putative susceptibility gene in B. distachyon was tested with a T-DNA insertion mutant and exhibits enhanced rust resistance, however, may be linked to changes in overall plant growth and development. Each source of rust resistance defies standard systems of characterization and includes some traits that are less desirable along with their resistance capabilities, for example: unstable expression due to environmental interactions, race specificity, or recessive gene action. However, the benefit of these sources of stem rust resistance may compensate for their less desirable traits.Item A Novel Mating Design to Optimize Genomic Selection Efficiency for Commercial Corn Breeding(2022-03) Sweet, PatrickIn many commercial corn (Zea. mays L.) breeding programs, lines are selected based only on general combining ability (GCA) during first-year trials. Selection for specific combining ability (SCA) is delayed until later trials, resulting in many unevaluated hybrid combinations. My objective was to determine whether a reciprocal testcross mating design enables simultaneous selection for GCA and SCA, while maintaining the same resources typical in first-year trials. Suppose B1 and B2 are Iowa Stiff Stalk Synthetic (BSSS) lines, whereas N1 and N2 are non-BSSS lines. In a reciprocal testcross design, progeny of B1 × B2 are testcrossed with N1 and N2, and progeny of N1 × N2 are testcrossed with B1 and B2. In 2019, grain yield and moisture of 1,642 hybrids from 10 BSSS and non-BSSS populations were measured at a median of three locations per hybrid across the upper Midwest. In 2020, a validation set consisting of 146 hybrids that were not tested in 2019 were evaluated at a median of five locations per hybrid. The GCA and SCA values were estimated using genomewide prediction with 11,000 SNP markers and the level of dominance was estimated using a subset of these markers. The sizes of training populations were kept constant, and the cross-year predictive ability of the reciprocal testcross design was compared with that of a standard, nonreciprocal design. Including SCA in the models marginally increased predictive abilities for reciprocal designs and the reciprocal designs produced higher predictive abilities than the nonreciprocal designs. The median level of dominance for grain yield was 1.08 indicating complete dominance. The results indicated that the reciprocal testcross mating design combined with genomic prediction could efficiently enable simultaneous selection for GCA and SCA earlier in a breeding pipeline.Item Original Pollination Records from University of Minnesota Fruit Breeding Program from 1908-1922(1922) Horticultural Research CenterItem Original Pollination Records from University of Minnesota Fruit Breeding Program from 1923-1929(1929) Horticultural Research CenterItem Original Pollination Records from University of Minnesota Fruit Breeding Program from 1930-1934(1934) Horticultural Research Center