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1
Holzbauer, Regina. "Economic values and responses to selection using selection indices in swine." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0003/MQ44183.pdf.
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Borrenpohl, Daniel. "Genomic selection can replace phenotypic selection in early generation wheat breeding." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1562957699157873.
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Borg, Randy Charles. "Developing Breeding Objectives for Targhee Sheep." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/9973.
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Breeding objectives were developed for Targhee sheep at different levels of prolificacy and triplet survival. Economic weights (EW) were derived for estimated breeding values (BV) from National Sheep Improvement Program genetic evaluations for 120 d weaning weight (WW), maternal milk (MM), yearling weight (YW), fleece weight (FW), fiber diameter (FD), staple length (SL), and prolificacy (PLC; lambs born/100 ewes lambing). A commercial flock was simulated, accounting for nonlinear relationships between performance and profit. Ewes were assumed mated to sires of specified BV and profit was derived from lifetime performance of lambs and replacement females from that lamb crop. Economic weights were determined as change in profit from use of sires with BV that were one additive standard deviation above the mean for each trait [1.98 kg for WW, 1.62 kg for MM, 2.90 kg for YW, 0..36 kg for FW, 0.99 microns for FD, 0.74 cm for SL, and 17.58 lambs/100 ewes for LC], while holding all other BV at breed average. Separate breeding objectives were derived for different ways of meeting increased nutrient needs (P = purchase hay, R = rent pasture, and L= limited flock size) and for different market lamb values (D = discounting lamb value for heavy weights, ND = no discount for heavy lambs). Based on replicated simulations, relative EW did not vary with prolificacy or triplet survival (P > 0.15) but were affected by feed costs and lamb market values (P < 0.01). Selection indexes were derived within and across simulated scenarios, and correlation (r) among indexes of > 0.90 indicated that an index could be used across multiple scenarios with little loss of selection efficiency. Indexes derived within feed cost scenarios (P, R, and L) and lamb value scenarios (D, ND) were strongly intercorrelated (r > 0.97). Correlations among average indexes for feed cost scenarios (0.97 for R and P, 0.70 for R and L; 0.85 for P and L) indicated that two feed cost scenarios could be used depending on whether winter forage was limited (L) or not (NL). The correlation between average indexes for these two scenarios was 0.78. Indexes were presented for combinations of feed cost and lamb value scenarios. Two indexes were suggested, representing the scenarios that apply to a large portion of Targhee producers. These indexes were for discounting heavy lambs with limited winter forage (D-L: 1.0 WW + 0.14 MM __ 0.76 YW + 1.22 FW __ 0.36 FD - 0.09 SL + 0.25 LC) and discounting heavy lambs with additional available forage (D-NL: 1.0 WW + 0.24 MM __ 0.34 YW + 1.65 FW __ 0.41 FD - 0.14 SL + 0.33 LC). For a standardized selection differential of one for the index, the expected changes in mean index value were $2.17 and $1.92 per ewe per generation for D-L and D-NL, respectively.Master of Science
4
Petropoulou, Smaragdi Panagiotis. "Temperature related factors as selection criteria in apple breeding." Thesis, Imperial College London, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261813.
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Todd, Darren Lindsay. "Implementation of genomic selection in UK beef and sheep breeding." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8766.
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Genomic selection (GS) has been adopted by the dairy cattle breeding industry and the opportunity exists to implement this technology in UK beef and sheep breeding. However, these sectors do not appear so readily predisposed to GS implementation. Following an introduction to GS in Chapter 1, Chapter 2 investigated the structure of the little-studied UK beef breeding sector. This provided estimates of key commercial and pedigree population parameters, for use in modelling genetic gain from GS. Terminal traits were found to be the dominant selection goals, with 85% of beef-sired commercial matings resulting in progeny being slaughtered at a prime age. Pedigree bulls disseminated the majority of genes in the sector via natural service. The correlation between the terminal selection index (TI) and the sale price of breeding bulls was moderate, suggesting a modest uptake of genetic technology in the sector. Chapter 3 estimated selection intensity for TI, generation interval and the dissemination rate of improved genes in the pedigree Limousin population. In order to predict the genetic gain achievable in using GS in beef and sheep breeding, Chapters 4 to 6 undertook deterministic selection index simulations, incorporating genomic information as correlated traits. In Chapter 4, GS was modelled for terminal beef traits, when incorporating carcass information and accounting for likely genotype by environment interaction. Using a training population of 2000 sires, this concept was predicted to offer 40% greater genetic gain than existing BLUP selection using pedigree phenotypes. Gene flow methodology projected the commercial value of this gain to offer a substantial return net of genotyping costs. Chapter 5 explored GS for maternal beef traits within the concept of a nucleus breeding scheme. Whilst greater genetic gain was predicted with GS than with conventional BLUP, the economic value of this gain was projected to be too low to justify such a scheme in the UK. Chapter 6 proposed a synergy between computer tomography (CT) phenotypes and GS in sheep breeding. Developing a genomic predictor from male selection candidates with CT phenotypes and conventional performance records was predicted to increase genetic gain by 55% over BLUP selection without CT traits. Introducing GBV contributed most of the accuracy in this scenario, suggesting that the existing performance recording structure in UK sheep breeding could in the future be replaced by GS using CT. In the general discussion, the potential for GS in other beef and sheep traits was considered in the light of the outcomes of these simulations. Given the lack of vertical integration in UK beef and sheep sectors, the drivers for implementation of GS are examined. Finally, the options for international cooperation and the possibilities offered by future genotyping technology are considered. It was concluded that implementation of GS incorporating beef carcass phenotypes was merited and could provide a platform for future GS implementation in other novel traits. Sheep GS with CT traits was considered a higher risk strategy, due to the lack of evidence for uptake of existing EBV technology.
6
Mazhar, Kehkashan. "Molecular genetic markers for selection and genome mapping in cattle." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260797.
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Lehtonen, Emily. "Breeding Site Selection and Breeding Success in Red-throated Divers (Gavia stellata): Implications for Wind Power Development." Thesis, Uppsala universitet, Institutionen för ekologi och genetik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-314976.
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Our alarming rate of resource exploitation and its consequences on the environment is fuelling an increase in sustainable energy production around the world. Wind power appears to be a particularly promising energy source relative to its environmental footprint, with the exception of potential negative effects of wind power on birds. Varying results from impact assessments around the world indicate that knowledge of both abiotic and biotic factors, as well as bird behavior and ecology, is required to assess the cumulative impact of any given wind farm on local bird communities. This study aims to assess the cumulative impact of a proposed wind farm on a threatened seabird, the red-throated diver (Gavia stellata), at one of its breeding "hotspots" in Sweden: the Holmöarna islands. Measurements of environmental variables in lakes on Holmöarna are combined with breeding surveys from 2012 to 2015 to assess which environmental variables may be associated with lakes that red-throated divers do or do not breed in, and which variables are correlated with breeding success. These results are combined with a literature review to assess the potential negative effects of the proposed wind farm on the breeding population on Holmöarna. The results show that average breeding success over the survey period was 0.35 fledged young per pair per year. No difference was found in environmental variables between lakes that divers had or had not bred in. Lake area/perimeter ratio and distance to the sea were significantly negatively correlated with breeding success, although distance to the sea was only significant for lakes with at least one successful breeding attempt during the survey period. Based on these correlations, 33 of a total 40 breeding lakes are shown to have relatively high area/perimeter ratios and long distances to the sea, which may pre-dispose divers breeding within them to low breeding success. These lakes are, therefore, identified as being at high-to-moderate risk of increased breeding failure if breeding success is further reduced as a result of external factors, including that of any negative impacts of the proposed wind farm. 31 of the 40 breeding lakes are also within 1 km of the proposed wind turbine sites, which may render red-throated divers breeding within them vulnerable to displacement as a result of wind farm-related disturbance. The literature review highlights the mechanisms that may determine the cumulative impact of the wind farm on red-throated divers in terms of collision mortality, habitat displacement, and barriers to movement. The strong sensitivity of red-throated divers to disturbance is considered to be the most likely driver of any negative effects of the wind farm. In this context, I thus argue the need for a precautionary approach to planning wind power developments in the vicinity of breeding red-throated diver populations.
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Firat, Mehmet Ziya. "Bayesian methods in the selection of farm animals for breeding." Thesis, University of Edinburgh, 1995. http://hdl.handle.net/1842/14854.
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The purpose of this thesis is to implement Bayesian methods to solve theoretical and practical statistical problems in the selection of animals for breeding. The thesis is therefore mainly on the calculation of posterior distributions of variance components and functions of them, and the construction of optimum Bayesian selection methods for a single quantitative trait and multiple traits. Half-sib family structures are considered throughout, although the theory considered is more general in its application. Conventional and Bayesian methods for variance components estimation are reviewed from an animal breeding point of view, with emphasis on balanced data, but unbalanced data are also discussed. In Bayesian statistics the necessary integrations in several dimensions are usually difficult to perform by analytical means. A Gibbs sampling approach, which yields output readily translated into required inference summaries, is applied to integrations using suitable families of prior distributions. Gibbs sampling output is then used to develop appropriate graphical methods for summarising posterior distributions of genetic and phenotypic parameters, and to calculate the posterior expectations of breeding values and the expected progress using different selection procedures. The selection of farm animals for breeding is treated as a decision problem in which the utility of choosing a given number of individuals is assumed to be proportional to the sum of the corresponding breeding values. The Bayesian selection procedure in this case is contrasted with conventional procedures based on point estimates of parameters including a method based on modified parameter estimates known as bending.
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Brassard, Jonathan Thomas. "Phenotypic selection in Impatiens pallida and Impatiens capensis." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61934.
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Diaz-Martin, Clara. "Correlation of predicted breeding values across environments in the presence of selection for direct and maternal breeding values." Diss., Virginia Tech, 1992. http://hdl.handle.net/10919/39438.
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A simulation approach was used to determine the effects of multitrait selection on the correlations of sire direct and maternal predicted breeding values across environments. True and predicted direct and maternal breeding values (BV) of sires were simulated for sires evaluated independently in two different environments. Prediction error variances and covariances among direct and maternal BV within environments were required for the simulation. To obtain the necessary input parameters, a variety of MME coefficient matrices were created and inverted to inspect relationship among accuracies and correlations of prediction errors in sire evaluation models. An empirical prediction equation to predict the necessary prediction error covariances was obtained. Divergent, directional and random multitrait selection was then practiced using direct and maternal predicted BV as selection criteria. Samples of 40 sires were randomly obtained from each selected population. Observed correlations between direct and maternal predicted BV across environments were compared to expectations derived from univariate distribution theory. Selection definitely affected the expectations. However, the adjustment developed from univariate theory appeared to accommodate the effect of selection in these expectations.Ph. D.
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Andersson, Erik W. "Gain and diversity in multi-generation breeding programs /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5629-0.pdf.
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Brown, Timothy P. (Timothy Phillip). "Selection indices in retrospect for dairy cattle." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59266.
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Selection differentials and selection indices in retrospect were calculated to determine the relative emphasis placed on production and type traits through bull selection. Indices in retrospect including only production traits indicated that, for Holsteins, fat yield was the trait most heavily selected for between 1978 and 1987, followed by protein percent and then milk yield. Fat percent and protein yield had negative index weights throughout the nine year period. In Ayrshires, similar weights were observed except that milk yield index weights were negative throughout the nine year period. It was found that the relative weight placed on type was small and did not affect the relative weights place on production traits. Within Holsteins, differences in bull selection when multiple services were required to successfully service a cow indicated that selection for overall size was reduced in later services. Within Ayrshires, there were no differences in any production or type trait within multiple services.
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Shadwick, Mark. "An investigation of the MLC beef bull index." Thesis, University of Newcastle Upon Tyne, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386691.
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Allali, Mohamed. "The efficiency of selection in a Moroccan sugar cane breeding programme." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239460.
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Robinson, David Lowell 1955. "RECURRENT SELECTION FOR GERMINATION SALT TOLERANCE IN ALFALFA (SALINITY, FORAGES, BREEDING)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/277015.
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Escamilla, Sanchez Diana Marcela. "Improving Breeding Selection of Seed Quality Traits for Food-Grade Soybeans." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/81963.
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Natto and sprout soybeans are produced using small-seeded soybeans and their production is a high value alternative to grow grain soybeans for food in U.S. The development of soybean cultivars with improved natto and sprout quality is crucial for maintaining and increasing the soyfood market. However, there is insufficient information on sprout soybean characteristics. Therefore, the first objective of this study was to evaluate seed and sprout traits as potential selection criteria and study the storage effect on sprout quality. Seeds can be a vehicle for transmission of pathogens capable of causing human illness. That is why, the second objective was to identify seed-borne pathogens on a commercial soybean cultivar and to evaluate different seed decontamination treatments. Finally, seed coat deficiency is an undesirable trait for natto soybean seeds because it causes inferior appearance of the product. Thus, the third objective was to identify quantitative trait loci (QTL) underlying seed coat deficiency (SCD) and associated markers. Results showed that seed size, high-, average- and low-quality sprout percentage, hypocotyl thickness and length and sprout yield are the most important variables for breeding sprout cultivars; and one-year seed storage at room temperature reduced sprout quality. Fusarium, Alternaria and Diaphorte were the most frequent genera isolated from soybean seeds, and 2% calcium hypochlorite and 5% acetic acid were promising seed disinfection treatments. A stable QTL, qSCD20_1, was identified across two years explaining up to 25% of the variation of SCD; and eight molecular markers tightly linked and nearby qSCD20_1 were identified. Information presented will be helpful for sprout and natto soybean cultivar development.Master of Science
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Stanek, John R. "Breeding habitat selection by rosy-finches in the San Juan Mountains, Colorado." Laramie, Wyo. : University of Wyoming, 2009. http://proquest.umi.com/pqdweb?did=1939351891&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Al-Doss, Abdullah 1963. "Selection of very nondormant alfalfa for increased winter and spring production." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277055.
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Regrowth and yield of 23 Middle Eastern (ME) cultivars and the elite cultivar Lew were evaluated for twelve regrowth harvests in pure stands and 50:50 mixtures with Lew in 1988 at Tucson, Arizona. Stem elongation rate and crown shoot development were measured on selected ME cultivars and Lew in the spring of 1988. No significant differences in yield were observed between mixtures and monocultures. Few significant differences were observed over all yields among ME cultivars and Lew. Cultivars from Saudi Arabia and Egypt produced more forage than Lew in spring harvests. These cultivars developed crown shoots precociously and had high stem elongation rates during the first week of regrowth. Most ME cultivars had higher leaf area and leaf:stem ratio than did Lew. These findings suggest that ME cultivars may be useful in improving forage yield during the winter and spring and forage quality in elite nondormant cultivars.
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Kruger, Narelle Lee. "Simulating the impact of marker-assisted selection in a wheat breeding program /." [St. Lucia, Qld.], 2005. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18989.pdf.
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Neves, Haroldo Henrique de Rezende [UNESP]. "Strategies to improve the efficiency of genomic selection in animal breeding programs." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/102766.
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000736380.pdf: 3145920 bytes, checksum: eb9040463ecaf8a423ca7772cda63410 (MD5)Esta tese compreende quatro diferentes estudos conduzidos a fim de avaliar estratégias alternativas para aumentar a eficiência de seleção genômica (GS) em programas de melhoramento animal. Um primeiro estudo foi desenvolvido com a finalidade de avaliar a performance preditiva de diferentes métodos estatísticos com base na informação de painéis de marcadores densamente distribuídos ao longo do genoma. Cinco diferentes características de uma população real de camundongos foram analisadas. Verificou-se que métodos com grandes diferenças conceituais apresentaram performance preditiva similar em algumas situações, também havendo variação na performance relativa dos métodos em função da característica analisada. O uso de diferentes variáveis resposta (pseudo-fenótipos) para estimação de efeitos de marcadores foi avaliado num segundo estudo, por meio da simulação de uma grande população de bovinos de corte, para a qual predições genômicas foram obtidas usando um procedimento de múltiplas etapas. Houve evidência de que provas desregredidas (dEBV) são mais apropriadas do que valores genéticos preditos (EBV) e médias ajustadas de desempenho da progênie (PYD), tanto para o treinamento de modelos quanto para a validação de predições genômicas. No terceiro estudo, procurou-se avaliar consequências em longo-prazo da aplicação de GS numa população de bovinos de corte sob seleção. Verificou-se grande benefício da aplicação de GS em cenários simulando seleção para características de qualidade de carne e reprodução de fêmeas. Houve evidência de que pode-se esperar maior benefício para GS, quando comparada à seleção por BLUP, no caso de características oligogênicas. Também foi possível inferir que em aplicações de GS, o uso de um critério de seleção em que se atribui maior peso a alelos favoráveis de menor frequência poderia proporcionar...
Improvements in production levels and product quality are needed in livestock systems to meet the growing world demand for animal-source foods. Besides this increasing demand, the productive sector must deal with constraints related to competition for land, greenhouse gas emissions and also due to hardening legislation in the fields of environment and animal welfare (FAO, 2011). In this context, animal breeding has played and will continue to play an important role to improve the efficiency of such production systems, especially in terms of competitiveness, safety, sustainability and biodiversity conservation (Harlizius et al., 2004). The main objective of animal breeding programs is to improve the performance of the next generations, through identification and reproduction of the animals with better genetic pool to efficiently produce in a specific environment (herein, superior animals). In the last decades, animal breeders succeeded in achieving this goal, mostly through the application of statistical tools grounded in quantitative genetics theory, what could be called as 'classical animal breeding'. In this case, the traditional prediction of the genetic merit of individuals (estimated breeding values, EBV) is obtained based on information of pedigree and phenotypes (own records and measures on relatives). With the advent of dense molecular marker panels, the implementation and design of breeding programs, especially in dairy cattle, had changed dramatically as a consequence of incorporating this new information to identify superior animals earlier and more precisely. Pioneer simulation studies drew attention of animal breeders to the possibility of making accurate predictions of the genetic merit of individuals by using genotypic information from dense marker panels, a process known as genomic selection (GS) (Nejati-Javaremi et al., 1997; Meuwissen et al., 2001). Other influential work ...
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Ignatiuk, Jordan B. (Jordan Blake). "Breeding biology and habitat selection of American crows in Saskatchewan parkland habitat." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60454.
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The breeding biology and nest-site selection of American crows (Corvus brachrhynchos) was studied in 2 areas of aspen parkland habitat in Saskatchewan in 1987 and 1988.Overall, density of nests at St. Denis averaged twice that found at Elstow and clutches were initiated earlier at St. Denis than at Elstow. Clutch size and hatching success did not differ between years or areas, but in 1987, nests at St. Denis produced nearly twice as many young as at Elstow.
Crows nested in willow, aspen, and other trees. Nest trees were larger than randomly-selected trees in both years and areas. At St. Denis, the area near active crow nests had, on average, more permanent wetlands, a greater proportion of pasture and wetland, and less area of cultivation than areas adjacent to random sites. At St. Denis, successful nests were closer to permanent water and had more permanent wetlands nearby than depredated nests, but discriminant function analysis could not correctly distinguish successful nests in either area. Selection of nest characteristics to evade predators does not appear to provide predictable advantages to breeding crows.
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van, Heelsum Anna Maria. "Selection strategies in marker assisted introgression, with special reference to pig breeding." Thesis, University of Edinburgh, 1997. http://hdl.handle.net/1842/13156.
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In this thesis several aspects of Marker Assisted Introgression (MAI) are investigated, keeping in mind the application of the methods to pig breeding. During the process of introgression of a desirable gene from a donor population into a recipient population, markers were used to identify the gene of interest as well as the background genome. The first part of this study deals with consequences of using markers of which the alleles could occur in both base populations. The effects were studied over 5 generations of backcrossing. Using a marker bracket was a much more reliable way to identify the introgressed allele than using a single marker. Applying selection on background (recipient) genotype gave a rapid decrease in the frequency of the introgressed allele, even when the marker alleles were nearly unique to the base populations. Selection on the probability of presence of the desired trait allele while giving preference to heterozygotes (that produce informative gametes that can more often be traced to the correct parent) gave a better retention of the introgressed allele. If possible it would be better to preselect each parental pair on uniqueness of their marker alleles. The second part of the thesis deals with fine mapping a QTL during its introgressing. First a tool was developed to measure the accuracy of the QTL position estimate and then different selection strategies were compared with respect to their ability to map to QTL as precisely as possible, their ability to rapidly recover the background (recipient) genotype and their ability to retain the desired QTL allele. A dense map of fully informative markers was assumed. Some of the simulations used modelled an idealised situation, nonetheless, the conclusions provide valuable information for current pig breeding practice. Furthermore, the rapid development of marker technology and maps means the methods can probably be applied in the near future with relatively minor modifications.
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Pretorius, Susan Mathilda. "Evaluation of the selection and breeding of Friesian horses in Southern Africa." Diss., University of Pretoria, 2003. http://hdl.handle.net/2263/26913.
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In this study, the selection and breeding of Friesian horses in Southern Africa were evaluated. Literature was reviewed for sUbjective and objective selection criteria in horse breeding with special reference to the Friesian. 852 Pedigree records from Friesian horses registered at the FPSSA and SAFBA, were included for pedigree analyses and 232 horses were measured for eight different linear body measurements. Only 25,7% of the population was found to be inbred. A regression of average inbreeding on year of the whole population, indicated a relatively slow increase in the rate of inbreeding. It is, however, suspected that this could be a conservative estimation, because of the limited pedigree information. The results indicated that the Friesian horse is normally of rectangular (height at withers: body length) shape. A large average difference between wither height and back height was observed. The cannon length measurements were proportional to overall size, no obvious deviations were observed. Pearson correlation estimates between the eight body measurements were mostly in accordance with other studies on horses reported in the literature. A sire model was fitted for the estimation of heritability for wither-, back- and croup height, body length, cannon circumference and cannon length. Estimates ranged from 0.30 for wither height to 0.57 for cannon circumference. The results indicate that South African breeders can apply body measurements in their selection programs for Friesians. From the results, guidelines were provided for establishing a database for Friesian horses in Southern Africa to ensure a scientific approach to selection and breeding.Dissertation (MSc (Agric))--University of Pretoria, 2003.
Animal and Wildlife Sciences
unrestricted
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Akpolat, Hacer. "Improvement of Tomato Breeding Selection Capabilities using Vibrational Spectroscopy and Prediction Algorithms." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574812034661898.
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Felts, James Vernon. "Dietary self-selection and feed restriction studies with growing and breeding turkeys." Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-07282008-135100/.
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Pretorius, Susan Mathilda. "Evaluation of the selection and breeding of Friesian horses in Southern Africa." Pretoria : [s.n.], 2005. http://upetd.up.ac/thesis/available/etd-08012005-171825.
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Neves, Haroldo Henrique de Rezende. "Strategies to improve the efficiency of genomic selection in animal breeding programs /." Jaboticabal, 2013. http://hdl.handle.net/11449/102766.
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Orientador: Sandra Aidar de QueirozCoorientador: Roberto Carvalheiro
Banca: Fernando Sebastián Baldi Rey
Banca: Rúsbel Raúl Aspilcueta Borquis
Banca: Fernanda Brito
Banca: Fabyano Fonseca e Silva
Resumo: Esta tese compreende quatro diferentes estudos conduzidos a fim de avaliar estratégias alternativas para aumentar a eficiência de seleção genômica (GS) em programas de melhoramento animal. Um primeiro estudo foi desenvolvido com a finalidade de avaliar a performance preditiva de diferentes métodos estatísticos com base na informação de painéis de marcadores densamente distribuídos ao longo do genoma. Cinco diferentes características de uma população real de camundongos foram analisadas. Verificou-se que métodos com grandes diferenças conceituais apresentaram performance preditiva similar em algumas situações, também havendo variação na performance relativa dos métodos em função da característica analisada. O uso de diferentes variáveis resposta (pseudo-fenótipos) para estimação de efeitos de marcadores foi avaliado num segundo estudo, por meio da simulação de uma grande população de bovinos de corte, para a qual predições genômicas foram obtidas usando um procedimento de múltiplas etapas. Houve evidência de que provas desregredidas (dEBV) são mais apropriadas do que valores genéticos preditos (EBV) e médias ajustadas de desempenho da progênie (PYD), tanto para o treinamento de modelos quanto para a validação de predições genômicas. No terceiro estudo, procurou-se avaliar consequências em longo-prazo da aplicação de GS numa população de bovinos de corte sob seleção. Verificou-se grande benefício da aplicação de GS em cenários simulando seleção para características de qualidade de carne e reprodução de fêmeas. Houve evidência de que pode-se esperar maior benefício para GS, quando comparada à seleção por BLUP, no caso de características oligogênicas. Também foi possível inferir que em aplicações de GS, o uso de um critério de seleção em que se atribui maior peso a alelos favoráveis de menor frequência poderia proporcionar ...
Abstract: Improvements in production levels and product quality are needed in livestock systems to meet the growing world demand for animal-source foods. Besides this increasing demand, the productive sector must deal with constraints related to competition for land, greenhouse gas emissions and also due to hardening legislation in the fields of environment and animal welfare (FAO, 2011). In this context, animal breeding has played and will continue to play an important role to improve the efficiency of such production systems, especially in terms of competitiveness, safety, sustainability and biodiversity conservation (Harlizius et al., 2004). The main objective of animal breeding programs is to improve the performance of the next generations, through identification and reproduction of the animals with better genetic pool to efficiently produce in a specific environment (herein, superior animals). In the last decades, animal breeders succeeded in achieving this goal, mostly through the application of statistical tools grounded in quantitative genetics theory, what could be called as 'classical animal breeding'. In this case, the traditional prediction of the genetic merit of individuals (estimated breeding values, EBV) is obtained based on information of pedigree and phenotypes (own records and measures on relatives). With the advent of dense molecular marker panels, the implementation and design of breeding programs, especially in dairy cattle, had changed dramatically as a consequence of incorporating this new information to identify superior animals earlier and more precisely. Pioneer simulation studies drew attention of animal breeders to the possibility of making accurate predictions of the genetic merit of individuals by using genotypic information from dense marker panels, a process known as genomic selection (GS) (Nejati-Javaremi et al., 1997; Meuwissen et al., 2001). Other influential work ...
Doutor
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Pegard, Marie. "New models for implementation of genome-wide evaluation in black poplar breeding program." Thesis, Orléans, 2018. http://www.theses.fr/2018ORLE2058/document.
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Les espèces forestières sont particulières à bien des égards par rapport aux autres espècesdomestiquées. Les arbres forestiers ont de longues phases juvéniles, entrainant de long et couteuxcycles de sélection et nécessitant une sélection en plusieurs étapes indépendantes. Bien que cetteméthode soit efficace du point de vue opérationnel, elle reste couteuse en temps et en ressources,entrainant une dilution de l’intensité et de la précision de sélection. Au vu de ces contraintes,les arbres sont de bons candidats pour la mise en oeuvre de l’évaluation génomique. La sélectiongénomique (SG) repose sur le classement et la sélection d’individus à partir de l’informationcontenu dans leur génome sans utilisé une étape d’évaluation phénotypique et ainsi accélérerle processus de sélection.Ce travail visait à identifier les situations, les critères et les facteursdans lesquelles la SG pourrait être une option réalisable pour le peuplier. Notre étude a montréque les avantages de l’évaluation génomique dépendent du contexte. C’est dans des situationsles moins avantageuse que l’évaluation génomique se montre la plus performante, elle profiteégalement de la densification de l’information génétique de faible à moyenne suite à une étaped’imputation de haute qualité. La sélection génomique pourrait être une option intéressante àstade précoce, où la précision de la sélection est généralement faible et la variabilité génétiqueabondante. Notre travail a également montré qu’il est important d’évaluer les performancesavec des critères alternatifs, comme ceux liés au classement, notamment lorsque ces critèresrépondent au contexte opérationnel du programme d’élevage étudiéForest species are unique in many ways compared to other domesticated species. Forest trees have long juvenile phases, leading to long and costly selection cycles and requiring selection in several independent stages. Even if this method is operationally effective, it remains costly in terms of time and resources, resulting in a diluted intensity and accuracy of selection.In view of these constraints, trees are good candidates for the implementation of genomic evaluation. Genomic selection (SG) is based on the classification and selection of individuals from the information contained in their genome without using a phenotypic evaluation step and thus accelerating the selection process, in order to identify the situations, criteria and factors in which SG could be a feasible option for poplar. Our study showed that the benefits of genomic evaluation are context-dependent. Genomic evaluation is most effective in theless-advantageous situations, it also benefits from low to medium density genetic information following a high-quality imputation step. Genomic selection could be an interesting option at an early stage, when the accuracy of selection is generally low and genetic variability is abundant.Our work has also shown that it is important to evaluate performance with alternative criteria,such as those related to ranking, especially when these criteria fit the operational context of the breeding programme under study
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Parkes, Sally J. "A comparison of methods for selecting untagged animals for breeding purposes." Thesis, Bangor University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273622.
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Masawe, Peter A. L. "Aspects of breeding and selecting improved cashew genotypes (Anacardium occidentale L.)." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386973.
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Ntladi, Solomon Magwadi. "Implementation of marker assisted breeding in triticale." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/18035.
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Thesis (MScAgric)--Stellenbosch University, 2011.ENGLISH ABSTRACT: Research into markers for the detection of genetic diversity and cultivar identification has become an important component of the genetic improvement of crops. However, the incorporation of marker assisted selection (MAS) as a tool for the identification and characterization of breeding material has not been fully implemented in the breeding of spring triticale at Stellenbosch University’s Plant Breeding laboratory (SU-PBL). The present study served as a case study in order to achieve this. The first part of the study concerned the detection of genetic diversity in 101 newly sourced triticale cultivars, from a USDA germplasm bank, together with five local control cultivars, in order to identify possible crossing parents. Eight SSR markers, including five derived from rye and three from wheat, and five agronomic characteristics were used to assess diversity. In seedling screening the foreign cultivars showed resistance towards the stem rust isolate used, but were mostly susceptible to the leaf rust isolate. Out of the 8 SSR markers tested, 7 markers were polymorphic and revealed 140 alleles varying from 12 to 26 with an average of 17.5 alleles per locus. The observed polymorphic information content (PIC) value ranged from 0.39 to 0.88 with an average of 0.70, indicative of the good discriminatory ability of the SSR markers. The data revealed that the South African cultivars were genetically closely related to cultivars from the USA and Canada. The second part of the study focused on the introgression of a blue aleurone layer gene (Ba), carried by a wheat cultivar, ‘Cltr1202STR’, and purple pericarp genes (Pp1; Pp3) also carried by a wheat cultivar, ‘Amethyst’, into a triticale background. Unfortunately the introgression of the purple pericarp genes failed. Two lines containing the blue aleurone layer, 11T023 and 11T028, were however successfully created. Molecular typing of these lines with SSR markers were able to show that BC4F1 line 11T023 (Ba) B was genetically similar to the recurrent parent ‘Agbeacon’; and that the BC4F1 11T028 line (Ba) A was closest to the ‘US2007’ recurrent parent. The study illustrated that MAS was a reliable tool for detecting genetic diversity in newly sourced germplasm, and assisted in making a backcross breeding effort more effective. The data generated from MAS could therefore clearly assist in making the SU-PBL breeding program more effective by moving, better informed, decision making toward data based partly on the genotype, thereby minimizing the risks associated with purely phenotypic based decisions.
AFRIKAANSE OPSOMMING: Navorsing rondom die gebruik van merkers vir die bepaling van genetiese-diversiteit en kultivar identifikasie is ‘n toenemend belangriker komponent vir die genetiese verbetering van gewasse. Die inkorporering van merker-bemiddelde-seleksie (MBS) as gereedskap vir die identifikasie en karaktarisering van telingsmateriaal is nog nie ten volle geïmplimenteer in die lente korogtelingsprogram van die Stellenbosch Universiteit Planteteeltlaboratorium (SU-PTL). Die studie het gedien as gevallestudie ten einde dit te bereik. Die eerste gedeelte van die studie het gehandel oor die tipering van die genetiese diversiteit van ‘n 101 kultivars verkry vanaf ‘n USDA kiemplasmabank saam met 5 plaaslike kontroles. Dit was gedien ten einde moontlike kruisings-ouers te kon identifiseer. Agt SSR merkers, insluitend vyf afkomstig van rog en drie vanaf koring, asook vyf agronomiese kenmerke is aangewend om die materiaal se diversiteit te tipeer. Saailingtoetsing is ook gedoen en het aangetoon dat die meeste kultivars weerstandig was vir die stamroes-isolaat, maar nie die blaarroes-isolaat nie. Van die agt SSR merkers getoets het sewe getoon om polimorfies te wees en het ‘n 140 allele gegee wat gewissel het vanaf 12 tot 26 per lokus met ‘n gemiddeld van 17.5. Die waargenome polimorfiese inligtings inhoud (PII) waarde het gewissel vanaf 0.39 tot 0.88 met ‘n gemiddeld van 0.70. Die merkers kon dus suksesvol diskrimineer. Die data het aangetoon dat die Suid-Afrikaanse kultivars genetiese die naaste verwant was aan die kultivars afkomstig vanaf die VSA en Kanada. Die tweede gedeelte van die studie het gefokus op die introgressie van ‘n blou aleuron-laag geen (Ba), afkomstig vanaf die koringkultivar ‘Cltr1202STR’, en twee pers-perikarp gene (Pp1; Pp3), afkomstig vanaf die koringkultivar ‘Amethyst’, na ‘n korog agtergrond. Ongelukkig het die oordrag van die pers-perikarp gene gefaal. Twee lyne wat die blou aleuron- laag bevat, 11T023 en 11T028, is egter suksesvol geskep. Tipering van die lyne met die SSR merkers het aangetoon dat die BC4F1 lyn 11T023 (Ba) B genetiese baie na aan die herhalende ouers ‘Agbeacon’ is en dat die BC4F1 11T028 lyn (Ba) A nader is aan die herhalende ouer ‘US2007’. Die studie het dus geïllustreer dat MBS gebruik kan word as ‘n betroubare manier om genetiese diversiteit te bepaal en by te dra tot die sukses van ‘n terugkruisingsprogram. Die data wat dus voortspruit uit MBS kan dus help om die SU-PTL se telingsprogram te assisteer in die besluitnemingsproses tydens teling deur beter genotipe gebaseerde besluite te neem wat die riskio van fenotipe gebaseerde besluite kan help verminder.
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Myszewski, Jennifer Helen. "A comparison of selection and breeding strategies for incorporating wood properties into a loblolly pine (Pinus taeda L.) elite population breeding program." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/75.
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The heritability of microfibril angle (MFA) in loblolly pine, Pinus taeda L., and its genetic relationships with height, diameter, volume and specific gravity were examined in two progeny tests with known pedigrees. Significant general combining ability (GCA), specific combining ability (SCA), and SCA x block effects indicated that there are both additive and non-additive genetic influences on MFA. Individual-tree narrow-sense heritability estimates were variable, ranging from 0.17 for earlywood (ring) 4 MFA to 0.51 for earlywood (ring) 20 MFA. Genetic correlations between MFA, specific gravity and the growth traits were non-significant due to large estimated standard errors.
Multiple-trait selection and breeding in a mainline and elite population tree improvement program were simulated using Excel and Simetar (Richardson 2001). The effects of four selection indices were examined in the mainline population and the effects of seven selection indices and four breeding strategies were examined in the elite population. In the mainline population, selection for increased growth caused decreased wood quality over time. However, it was possible to maintain the overall population mean MFA and mean specific gravity at levels present in the base population by implementing restricted selection indices. Likewise, selection for improved wood quality in the elite population resulted in decreased growth unless restricted selection indices or pulp indices derived from those of Lowe et al. (1999) were used. Correlated phenotypic responses to selection on indices using economic weights and heritabilities were dependent on breeding strategy. When a circular mating system (with parents randomly assigned to controlled-crosses) was used, the index trait with a higher economic weight was more influential in determining correlated responses in non-index traits than the index trait with a lower economic weight. However, when positive assortative mating was used, the index trait with a greater variance was more influential in determining correlated responses in non-index traits than the index trait with a lower variance regardless of economic weight.
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Butler, Robert William. "Habitat selection and time of breeding in the Great Blue Heron, (Ardea herodias)." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/30965.
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This thesis examines the causes and consequences of habitat selection and timing of breeding of the Great Blue Heron (Ardea herodias). My general hypothesis was that the duration of low tides and seasonal abundance of prey strongly influenced the location of colony-sites; timing of the breeding season; habitat shifts; and the use of space by foraging herons of different age- and sex-classes.
I studied Great Blue Herons along the Pacific coast of Canada for five breeding seasons and four winters. Breeding herons were studied at a colony of 85 to 100 pairs on Sidney Island near the town of Sidney, and periodic visits were made to about 40 other colonies around the Strait of Georgia, British Columbia. At Sidney, I studied the foraging behaviour, food availability, habitat use and reproductive success in detail. At other colonies, I recorded the reproductive success of herons, located their main feeding areas and searched for nests of a predator, the Bald Eagle. In the non-breeding season, I investigated the foraging behaviour, dispersion pattern and habitat shifts of juvenile and post-breeding adult herons in the Fraser River delta.
I hypothesized that heron colony-sites were located near food supplies or away from predators. Twenty-nine of 33 colony-sites were located within 6 km of their main feeding site. The number of heron pairs was slightly greater where eagles nested in high abundance than where eagle abundance was low, contrary to the hypothesis that breeding herons avoid areas with active eagle nests.
I hypothesized that herons began breeding in spring shortly after females acquired enough food energy to make eggs, or so chicks were in nests when food was most plentiful to their parents. Egg-laying began about 9 days after a
female's daily food intake crossed an energy threshold of 1715 kJ/day, whereas the peak availability of food energy to adults occurred about 35 days before the peak food demands of their chicks. Food intake rates by adults increased gradually in March and April with the increasing duration of low tides and the inshore movement of fishes. Adult food intake rates reached a peak in May when sea perch were most abundant, and diminished through June and July.
Most juvenile and adult female herons foraged on beaches from February to October and in marshlands and grasslands from November to January. Some males returned to territories along riverbanks in August and remained there until the start of the next breeding season in March.
I tested the hypothesis that herons leave foraging habitats in autumn when they can no longer catch enough food or when interference from conspecifics reduced foraging intake rates below a threshold required to maintain their energy balance. In October and November adults moved to marshlands and juveniles moved to grasslands when they could no longer maintain daily energy balance on beaches as a result of declining duration of low tides and food intake rates. Interference competition was too infrequent to explain habitat shifts by adult or juvenile herons in autumn.Science, Faculty of
Zoology, Department of
Graduate
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Beattie, Aaron D. "Application of marker-assisted selection to breeding of common bean, Phaseolus vulgaris L." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ33207.pdf.
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Stella, Alessandra. "Strategies for applying marker assisted selection in nucleus breeding schemes in dairy cattle." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ56295.pdf.
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Hocking, Daniel J. "Gray treefrog breeding site selection and offspring performance in response to forest management." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5103.
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Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on October 26, 2007) Includes bibliographical references.
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Hewitson, Stacy. "Habitat selection by breeding American black ducks (Anas rubripes) in northeastern Nova Scotia." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22739.
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Habitat selection by breeding black ducks (Anas rubripes) was studied in Antigonish County, Nova Scotia during April-September 1990 and 1991.Black duck pairs selected deciduous shrub ponds and sparsely vegetated ponds and avoided estuarine marsh and large lake habitat. Hens with broods preferred the deciduous shrub habitat while they avoided large lakes.
Black duck pairs appeared to use the distance to a brood-rearing pond as a cue in site selection. The closer a pond was to a suitable rearing pond the more likely it was occupied by a pair, regardless of food or cover resource availability. Black ducks, however, likely used site attributes such as the perimeter of the pond, the availability of aquatic invertebrates and the relative abundance of alder, willow and dead timber as cues in the selection brood-rearing habitat.
Black duck duckling survival, an estimate of recruitment, was the highest on preferred deciduous shrub ponds. Duckling survival was also higher on ponds with only one brood as opposed to ponds with several broods.
The most productive habitat for black ducks in the Antigonish study area were isolated, deciduous shrub ponds influenced by beaver activity. Black duck population numbers can be enhanced by managing local beaver populations.
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Argüelles-Ticó, Araceli. "Sexual selection, breeding systems and melanin-based plumage colouration in plovers Charadrius spp." Thesis, University of Bath, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.582832.
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Documenting behavioural and morphological differences across populations reflecting local adaption is of large interest to biologists. Yet, natural, geographic variation in targets and intensity of selection within species has been vastly underexplored. Here I focus on how the extraordinary diversity of breeding systems exhibited across multiple populations of plovers may influence ornamentation. Using data from nine geographically distinct populations of Kentish (Charadrius alexandrinus) and snowy plovers (C nivosus) I explore the variation in brood care and found extensive differences across populations in the duration of care and timing of brood desertion. Biogeographical parameters seem to partly explain the observed diversity of care patterns. I subsequently show that the differences in melanin-based plumage ornamentation across populations were predicted by the breeding system and geographic and climatic factors. I argue that geographic variation in intensity of sexual selection as associated with the diversity in breeding systems may shape individual phenotypes. To corroborate that proposition, I investigate whether the signalling function of the ornaments varies across populations. I show that melanin-based plumage traits are honest signals of parental care in two distinct populations, despite differences between both populations in the extent and direction to which both sexes adjust parental care in response to ornamentation. In my final chapter I aim to explore a potential mechanistic basis of the diversity in ornamentation by investigating correlations between melanic plumage traits. The correlations between plumage traits are highly variable across populations. Such apparent phenotypic plasticity suggests that local selection pressures influence the expression of melanisation. In sum, in my thesis I show that the behavioural and morphological outcomes of local adaptive regimes provide a wealth of diversity in natural history between populations. Exploring this natural variation at a behavioural, physiological and genetic level is likely to substantially advance our understanding of what constitutes a wild animal's phenotype.
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Sousa, Bridget Frances. "ECOLOGY OF MATING PATTERNS AND SEXUAL SELECTION IN DICKCISSELS BREEDING IN MANAGED PRAIRIE." UKnowledge, 2012. http://uknowledge.uky.edu/biology_etds/17.
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Males of many species have elaborate phenotypes that are absent in females and that are thought to be the result of sexual selection. Sexual selection requires: (i) variance in male mating success, (ii) variation in male phenotype, and (iii) covariation between male mating success and male phenotype. Environmental conditions influence these factors, and management practices that alter environmental conditions have the potential to shape mating patterns and sexual selection. I investigated the hypothesis that the frequency of fire, used to manage tallgrass prairie, affects the mating patterns and process of sexual selection in the organisms breeding in managed prairies.
I studied dickcissels (Spiza americana), a small songbird resident in tallgrass prairie. I first examined mating patterns and sexual selection in dickcissels independent of burning regime. I found variation among males in the number of mates attracted, in the number of offspring sired with each mate, and the offspring sired with the mates of other males. I found a positive association between social mates and siring success, but no evidence for an effect of breeding density or synchronous nesting on mating success. Male dimorphic traits, size, song, and plumage, showed between-individual variation but selection gradients were weak and often fluctuated between the years of study.
I next examined patterns of mating success in plots burned on a variable schedule. I found little evidence that burning influenced either the mean or the variance in social mating success, paternity, or male phenotype. Burning regime also had no influence on sexual selection gradients with the single exception of selection on tarsus length. Temporal variation was more important for patterns of mating success and sexual selection gradients on male traits than was burning regime. The demography of dickcissels in the breeding season suggests, however, that habitat management on a larger scale may be more influential. My findings extend our understanding of sexual selection in birds and the effects of management on the factors required for sexual selection and the magnitude of selection.
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Franco, Aldina M. A. "Habitat selection and breeding ecology of lesser kestrels Falco naumanni : implications for conservation." Thesis, University of East Anglia, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398500.
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Through an understanding of the lesser kestrel Falco naumanni habitat preferences and breeding ecology it is possible to determine the causes responsible for the species decline and suggest conservation measures. This study was conducted in the Iberian Peninsula during the lesser kestrel breeding period. Unlike Spain, nest site availability was found to be a constraint for the lesser kestrels in Portugal. The model for selection of buildings indicated that this species prefer buildings with many roof and wall cavities and surrounded by extensive agriculture. In Portugal and Spain, the villages selected by lesser kestrels had many old buildings and monuments, were located in areas with few rivers, and low percentage cover of cereals, olive groves and forest. Habitat preferences were determined using telemetry and transect count data and the two methods provided similar results. The effectiveness of radio tracking and visual sighting transect data was compared and the costs and benefits of each technique were assessed. Telemetry resulted in a larger number of significant differences between the habitats, but the costs were higher. Telemetry also required more effort to set up and collect the data. Transects were a cheaper technique but telemetry allowed areas with no roads to be covered. Findings indicate that lesser kestrel conservation is strongly dependent on the maintenance of extensive agriculture characterised by a rotation of cereal and grazed fallow. Abandonment of traditional agriculture and the recent changes in the agrienvironmental programme support, which favour afforestation and intensification, are jeopardising the future of cereal steppes and the lesser kestrel. Telemetry data indicated that lesser kestrels prefer to forage close to the colony. In steppe habitats, the protection of such foraging habitats within 3-km from the colonies could be an effective conservation measure. Vlll
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Brown, Jack. "The efficiency of selection in the early generations of a potato breeding programme." Thesis, University of St Andrews, 1988. http://hdl.handle.net/10023/7107.
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The efficiency of selection in the early generations of a potato breeding programme is examined. A number of unselected potato (Solanum tuberosum L) clones were grown in a glasshouse, from true botanical seed, and thereafter in the field at two locations (a seed site and a ware site) for three consecutive years. At each stage, a number of tuber characteristics were visually assessed and yield plus the yield components were recorded. Four potato breeders visually assessed the produce from each clone after harvesting each years trials and were in good agreement as to which clones would be selected in each environment. Selection for visually assessed characters in both the glasshouse and first clonal year produced a desirable response. However, such selection carried a high cost in terms of losing clones with commercial potential. Selecting clones for yield in the seedling and first clonal year was only marginally more effective than a random reduction in number of genotypes, while selection in the second clonal year appeared to be somewhat more effective as judged by performance in later generations. Comparison of a random sample of clones with ones from the same crosses which had been selected at the seedling and first clonal year stage was at best random, with some suggestion, however, of a negative effect. The causes behind the inefficiency of selection were found to be complex. The inefficiency was ascribed, at least in part, to (i) the inaccuracy of assessment on single plant plots; (ii) the "carry-over" effect of the mother tubers and (iii) selection under a short growing season. Although there was a formally significant interaction between progenies and environments, the rank of the mean of a cross remained relatively consistent over different growing conditions. It was found that the mean and square root of the variance obtained from breeders' preference in any of the environments provided a good basis for prediction of the number of clones in each cross which would exceed (or equal) a given target value. The square root of the variance added increasingly to the accuracy of the prediction as the target value increased but was never a major component in such predictions. When the predictions were used to provide ranking of the crosses, the rank correlations showed good agreement between the different environments and between observed and expected ranks. There was no evidence to suggest that univariate cross prediction for any of the other characters under study would not be effective. A new cultivar is unlikely to be successful simply because of high expression for a single character, but will rather be an all round improvement over cultivars already available. Three methods of multivariate cross prediction were therefore examined namely multivariate probabilities, sum of ranks and the frequency of genotypes in a sample that transgress set target values. The characters total tuber weigh t, mean tuber weight, number of tubers and regularity of tuber shape were examined. It was found that a sample as small as 25 clones provided good predictions (as judged by the observed frequencies in a larger progeny sample examined in various environments). The best estimates were obtained using multivariate probabilities based on the means, within progeny variances,. and the phenotypic correlations between variates. The ranking of crosses according to these multivariate probabilities provided good indications of the number of clones which survived selection in an actual breeding scheme. Thus it is suggested that an empirical examination of a sub-sample of the progeny from a cross could be used to determine the crosses which would have the highest probability of producing improved, potato cultivars. Selection of crosses rather than individual clones has several advantages which would favour such techniques being used in the early generations of a potato breeding programme. Cross prediction based on parental performance also provided an indication of the crosses, .and parents, .which would give the highest frequency of desirable recombinants. These predictions were not as accurate as those derived from examination of a sub-sample of progeny from each cross. But they would allow an earlier, and hence powerful, method of prediction.
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Shateryan, Djavad. "Evaluation of three cycles of recurrent phenotypic selection for forage yield in orchardgrass and timothy." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=26140.
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Three cycles of recurrent restricted phenotypic selection (RRPS) were carried out on two cultivars each of timothy (Phleum pratense L.) and orchardgrass (Dactylis glomerata L.). The selections were conducted at the E. A. Lods Agronomy Research Center of Macdonald Campus of McGill University from 1984 to 1988. Individual plant selections were based on dry matter yields of 25 plants. Within each of 16 grids, the five highest yielding genotypes were selected (i.e. 80 genotypes overall) and allowed to interpollinate. Equal weights of seeds from each of the 80 selected plants were mixed in each cycle. Evaluation trials were carried out in both sward and spaced stand from 1989 to 1993 to assess the effectiveness of selection in improving dry matter yield. Several other morphological and physiological characteristics of cycles were recorded to find possible associated changes.Three cycles of RRPS were not effective in increasing forage dry matter yields. The lack of response may be due to a narrow genetic base in the source populations and/or the population size under selection may have been too small, resulting in inbreeding depression. Another explanation for the ineffective selection may be non-random pollination among selected plants. The selection for forage yield produced some minor changes in other characteristics. There was a tendency towards increased plant height and circumference in orchardgrass; however, for timothy, height and circumference were reduced by selection. Cycle 3 of Avon orchardgrass was one day later in maturity and there was also a tendency for later maturity for timothy.
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Green, Ronald T. "Evaluation of optimum and near optimum pair selection methods for increasing predicted relative net income in Jersey cattle." Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/45650.
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To evaluate the importance of non-linear relationships between Relative net income per day of productive life (RNI/DPL) and individual traits, 921,915 potential offspring were simulated from all possible matings of 20,487 Jersey cows and 45 active AI sires. Predicted milk yield, fat yield, and 13 linear type traits of potential progeny were used to predict RNI/DPL of all potential progeny.
Five methods of mate selection and pairing were evaluated for their effectiveness in choosing mates and the amount of computer time required to choose those pairings. Results of a linear programming (LP) method were used as a comparison for the other four more easily applied methods. Two of the other four methods were not significantly (P > .01) different from the LP method. Although the random pairing method was significantly different, similarity of results, for this method indicated non-linear relationships between RNI/DPL and individual trait scores are of minor importance. A11 four methods used considerable less computer time than the LP method.
Analysis of variance for predicted RNI/DPL (all possible offspring) indicated herd, dam within herd, sire, and inbreeding class to be significant (P < .01) variables in determining RNI/DPL. However the sire by dam within herd interaction did not significantly affect RNI/DPL, again indicating non-linear relationships between traits and RNI/DPL were not very important.
Regressing PDâ s, Clâ s, and their crossproducts for milk yield, fat yield, and 13 linear type traits showed the relative importance of crossproducts to be minimal in comparison to the linear ellects of parental genetic evaluations.
Master of Science
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Moride, Yola. "The effect of selection for growth rate on growth hormone levels in the laboratory mouse /." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65356.
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Verges, Virginia Laura. "BREEDING FOR FUSARIUM HEAD BLIGHT RESISTANCE IN SOFT RED WINTER WHEAT." UKnowledge, 2004. http://uknowledge.uky.edu/gradschool_theses/234.
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Fusarium graminearum, the causative agent of Fusarium head blight, is an economically important pathogen of wheat (Triticum aestivum). Breeding Fusarium head blight (FHB) resistant wheat requires knowledge of the underlying genetic control of FHB resistance. Genetic parameters for FHB resistance and five related traits were estimated in three populations at two locations and in two years. Moderate broad sense heritabilities for FHB severity and Fusarium damaged kernels (FDK) were observed. Incidence of FHB and the toxin deoxynivalenol (DON) accumulation had low to moderate broad sense heritabilities. Correlations between FDK and severity and FDK and DON were moderate to high in the three populations and do support indirect selection for FHB severity or DON based on FDK data alone, but it is important to be cautious in years with a high disease pressure when FHB resistance could be masked. A cycle of among-family and within-family selection cycle was conducted in 2003. Actual selection gain was higher than predicted gain based on variance components in 2003 in the within-family selection study. One population had also a strong response for low DON in the among-family selection study. The observed results suggest that selection for FHB resistant genotypes could be achieved with a recurrent selection scheme. Along with conventional breeding, molecular techniques are being used in breeding for FHB resistance. A first genotypic screening of the three populations showed Population 2 had the presence of a resistance allele form the resistant Chinese cultivar Sumai 3. Although Populations 1 and 3 did not have the resistance allele, the results suggest other sources of resistance might be present in these two populations.
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Raj, Towfique. "Molecular signatures of natural and artificial selection in mammalian genomes." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609021.
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Hoffstetter, Amber L. "Assessing genome wide breeding strategies for economic traits in soft winter wheat and their impact on genetic architecture." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1448825514.
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Rönnegård, Lars. "Selection, maternal effects and inbreeding in reindeer husbandry." Uppsala : Dept. of Animal Breeding and Genetics, Swedish Univ. of Agricultural Sciences, 2003. http://epsilon.slu.se/a370.pdf.
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Papazoglou, Fotini. "Aspects of habitat selection in the sedge warbler Acrocephalus schoenobaenus in Sussex." Thesis, University of Sussex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360490.
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Breault, Andre Mario. "Breeding distribution, habitat selection and factors affecting coloniality in eared grebes in British Columbia." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/28922.
Full textAbstract:
In this study, I first describe distribution and abundance of breeding Eared Grebes {Podiceps nigricollis) in British Columbia. Second, I characterize and examine the relationships between nesting habitat and nest site selection on breeding group size. Finally, I. examine effects of colony size, nesting chronology and nesting synchrony on reproductive success at Eared Grebe colonies.
I surveyed 421 wetlands in 1985 and 1986 and located 47 lakes used by nesting Eared Grebes. Those 47 lakes accomodated from a low estimate of 1761 to a high estimate of 4474 pairs. Breeding abundance, calculated from adult, nest and young counts, ranged from single pairs to more than 590 pairs per lake. Breeding took place in shallow lakes of various sizes, subject to extensive variations in water levels. Breeding abundance was positively correlated with lake area. Fewer breeding pairs utilized nesting areas close to shore (in shallower water) than nesting areas far from shore (in deeper waters). Nesting areas close to shore were found in smaller lakes and were used less often in consecutive years than nesting areas far from shore, presumably because of lower habitat predictability. An experiment with unattended artificial nests showed that nest predation was higher far from shore than close to shore. Nesting areas close to shore were used by small groups. These maximized concealment by being located in denser vegetation. Nesting areas far from shore were used by larger groups and were
located in more open areas.
On both years, adults arrived at nesting lakes in April and May, started laying on 27 May and departed from, nesting areas in late July and- early August. Nesting was significantly earlier and reproductive success per pair was significantly higher in 1985 than in 1986. A .stepwise multiple regression examined effects of colony-size, synchrony and chronology on nesting success. Only nesting chronology accounted for differences in nesting success. Late nesters were not birds attempting to renest. Instead, there appeared to be qualitative differences across colonies that were related to ages of breeders.
Eared Grebe colonies are likely not formed from passive aggregation at limiting resources and there are likely no foraging benefits from colonial nesting. Nesting colonies could increase detection and mobbing of predators, but no evidence supported this. Anti-predator benefits of coloniality might have been masked by differences in breeding chronology and synchrony, or were missed because of low sample size.Science, Faculty of
Zoology, Department of
Graduate