Academic literature on the topic 'Breeding selections'
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Journal articles on the topic "Breeding selections"
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Shelbourne, C. J. A. "Maintaining genetic variation in breeding populations of Radiata pine in New Zealand." Silvae Genetica 68, no. 1 (February 1, 2019): 9–13. http://dx.doi.org/10.2478/sg-2019-0002.
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Abstract Advanced generation selection (AS) for the future breeding population (BP), becam a focus of tree breeders‘ thinking in the mid 1970s., particularly with Pinus radiata in New Zealand (NZ). Multitrait selection among families was generally recommended, but this reduced genetic variation in the future breeding population. From Shaw and Hood‘s (1985) stochastic simulation, later confirmed by Rosvall, Lindgren and Mullin‘s (1998) stochastic simulation on Norway spruce, it was realised that selecting within families rather than among families of a new breeding population avoided any reduction of genetic variation in the BP. Heritabilities were low for seedling within-family selection but clonal replication within families should strongly increase heritabilities. Gains from cloned versus seedling populations of equal numbers of plants were also deterministically simulated (Shelbourne et al. 2007), and balanced (within-family) selection gains from the cloned populations were all higher than seedling equivalents at heritabilities of 0.5 and under. The late P.A. Jefferson‘s (2016) Breeding Management Plan (which will be soon superceded) contains a re description of New Zealand (NZ) radiata pine breeding. Selections were made in crosses from the earlier program and OP see and scion material were collected from all 360 selections. OP family tests of selections have been planted at 11 sites in NZ and 7 in New South Wales and Tasmania, and scions of their female parents have all been grafted at an archive. Crosses made in the archive are being cloned and the programme was committed to within-family selection to retain genetic variance for the future closed breeding population. Clonally-replicated testing paired with within-family selection is the solution for balancing long-term gain and diversity in BP and PP.
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León, Lorenzo, Raúl de la Rosa, Diego Barranco, and Luis Rallo. "Breeding for Early Bearing in Olive." HortScience 42, no. 3 (June 2007): 499–502. http://dx.doi.org/10.21273/hortsci.42.3.499.
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The initial results of a comparative field trial of the first 15 selections of the olive (Olea europaea L.) breeding program of Cordoba, Spain, are presented. These selections came from crosses among ‘Arbequina’, ‘Frantoio’, and ‘Picual’ that were also included in the trial as controls. The trial was planted in July 2001 in a randomized block design with 16 replications and was systematically evaluated for earliness of bearing, vigor, crop, and yield efficiency from 2001 to 2005. Significant differences among selections were found for all characters measured. A greater proportion of early-bearing genotypes than in previous cultivar collections were found, whereas mean accumulated yield was similar to former evaluations. Therefore, the shorter unproductive period obtained in this work seems to indicate that the selection of seedlings for a short juvenile period has provided a shorter unproductive period of the subsequent new cultivars. No correlation between vigor at the seedling stage and vigor in the corresponding adult vegetative propagated selection was found. If the data presented here are confirmed further, some early-bearing cultivars could be suggested as new olive cultivars, the first obtained by cross-breeding in Spain. Additionally, some of them also show a low vigor and could be adapted to high-density hedgerow orchards.
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Nonaka, Keisuke, Masayuki Kita, Yoshinori Ikoma, Hiroshi Fukamachi, Atsushi Imai, Terutaka Yoshioka, and Masahiko Yamada. "Genetic Differences and Environmental Variations in Carotenoid Contents of Fruit Flesh in Parental Population Used in Citrus Breeding in Japan." Journal of the American Society for Horticultural Science 137, no. 4 (July 2012): 243–49. http://dx.doi.org/10.21273/jashs.137.4.243.
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To aid the breeding of citrus (Citrus sp.) for high carotenoid content, we assayed the fruit flesh of 48 cultivars and selections within a parental population consisting of both old and new cultivars and selections at two locations in Japan. The mean total carotenoid (CAR) content across all 48 cultivars and selections over the two locations was 26.59 μg·g−1 fresh weight (FW). The most prominent carotenoid was β-cryptoxanthin [BCR (12.09 μg·g−1 FW)] followed by violaxanthin [VIO (8.04 μg·g−1 FW)], ζ-carotene (2.27 μg·g−1 FW), phytoene (1.86 μg·g−1 FW), and β-carotene (0.96 μg·g−1 FW). Broad-sense heritabilities of CAR, BCR, and VIO were 0.80 or greater based on a sample of five fruit on one tree per location in one time sampling for 1 year in a location, which were revealed to be large enough for gauging the genetic variation. The mean CAR and BCR contents in a cultivar and selection group in advanced generations were nearly the same as in the initial population, suggesting no or little selection pressure on carotenoid content in the citrus breeding so far. High carotenoid contents in cultivars and selections released or selected recently, which have high fruit qualities, suggest their high potential for combining high fruit quality and high carotenoid content in breeding. We showed that the critical phenotypic value used in selecting hybrid seedlings can be determined from the estimate of environmental variance.
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Strefeler, Mark S., and Robert Quen. "Breeding for Drought Tolerance in New Guinea Impatiens." HortScience 30, no. 4 (July 1995): 778D—778. http://dx.doi.org/10.21273/hortsci.30.4.778d.
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Six commercial cultivars (Anna, Aurore, Danhill, Danlight, Melanie, and Thelca), one drought-tolerant cultivar (Orangeade), nine breeding selections, and one check genotype of Impatiens hawkeri Bull were evaluated for differences in drought tolerance based on water loss and time to wilt. The six commercially available cultivars had significantly higher mean water loss than the breeding selections and `Orangeade'. These cultivars wilted in 5.11 days vs. 7.33 for `Orangeade' and 9.10 for the breeding selections. These results suggests that sufficient variability exists in New Guinea impatiens germplasm for the reduction of water loss to improve drought tolerance. Regression analysis revealed that total transpirational water loss 96 h after withholding water was an excellent predictor of the time to wilting (a simple measure of drought tolerance) after water was withheld (R2 = 0.95). Thus, a simple, efficient, and objective method for selection of drought-tolerant genotypes has been developed for New Guinea impatiens. A comparison of offspring to parental genotypes showed that, after only one cycle of selection, water loss was significantly reduced by more than 30%. These results suggest that there is sufficient genetic variability present for the development of more drought-tolerant cultivars.
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Cantor, Maria. "(244) Genetic Breeding of Gladiolus hybridus in Romania." HortScience 41, no. 4 (July 2006): 1041D—1041. http://dx.doi.org/10.21273/hortsci.41.4.1041d.
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Gladiolus is one of the most popular flower crops grown in Romania. The breeding program at the University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca of this species has been especially focused on the improvement of main characteristics, such as color, number and form of florets, plant height, multiplication capacity, diseases resistance, etc. A program for genetic breeding of gladiolus varieties using different genitors (Romanian and foreign cultivars) was initiated. An intraspecific crossing between cultivars has been made followed by clonal selection and vegetative multiplication of the selections. In this paper, we show 15 new gladiolus selections, which were observed and analyzed in 2004–05. The selections obtained have a great uniformity of their morphological characteristics. These selections are more vigorous, producing greater number of florets with superior quality, have new colors of flower, and are distinguished by a long blooming time. The intraspecific variability of the above-mentioned characteristics was more than low, and rarely medium, high, or very high. These data suggest fair possibilities to choose the best selections that will be proposed for testing and homologation as new cultivars. The hybrids represent a step forward in combining high qualities in gladiolus. They will contribute to improving the assortment of gladiolus for cut flowers, landscape, or as genetic material, which can be used for new crossing in order to obtain new cultivars. Scientifically, a series of findings appeared considering the combining capacity of genitors, transmission of some useful qualities, and other aspects that contribute to improve of the new varieties.
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Khanizadeh, Shahrokh, and Deborah J. Buszard. "New Strawberry Selections from the Quebec Breeding Program." HortScience 30, no. 4 (July 1995): 768A—768. http://dx.doi.org/10.21273/hortsci.30.4.768a.
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Promising 1989 strawberry selections from the Agriculture Canada/McGill Univ. breeding program have been evaluated since 1990 at three different sites in Quebec. `Kent', `Glooscap', `Honeoye', `Bounty', and `Veestar' were used for comparison. Yield, average fruit weight at each harvest, firmness, color, taste, and other fruit characteristics were evaluated. SJ89288-2 had the highest yield with large fruit. SJ89700-1 and SJ89264-6 produced similar yield to `Kent' and `Glooscap', with firm and large fruit. SJ89700-1 had bright red skin color and SJ89264-6 had bright pale red color. Both are suitable from fresh-market and pick-your-own (PYO). SJ8976-1, another selection, had a firm, large, bright pale red fruit. All four selections have good shelf life quality and will be tested at four sites during 1993–95.
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Маkоvеi, M. D. "The breeding method and its influence on the intensification of the tomato selection process." Vegetable crops of Russia, no. 5 (October 30, 2020): 43–48. http://dx.doi.org/10.18619/2072-9146-2020-5-43-48.
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Relevance. The article presents the results of using three different selection methods to obtain new forms of tomato that combine high productivity with resistance to high-temperature stress factor.Methods. Eleven hybrid combinations were used as experimental material. Selections were made starting with the offspring of the F1 generation. Three different methodological approaches were used: 1 – step-by-step alternation of sporophytic-gametophytic selections under high temperature pressure; 2 – only gametophytic selection using heat-treated pollen for pollination; 3 – traditional selections based on a high value of indicators of the studied traits. In each of the variants of the experiment, we studied: the heat resistance of offspring at different stages of ontogenesis – "sporophyte-gametophyte"; the duration of the vegetation period of plants; the fruit formation; the total yield. The offspring of the most stable and productive plants isolated from different hybrid combinations were combined in the populations in each variant of the experiment and a comparative analysis and evaluation of the effectiveness of the methods used was carried out.Results. It is shown that the combination of step-by-step sporophyte-gametophyte selections under the action of high-temperature regimes (43°C and 45°C), at early stages (F1–F3) lead to more stable, productive offspring in F5-F7 both for sporophyte and gametophyte traits, compared to using only gametophyte selections and stronger differences relative to the control variant. The gradual alternation of selections at different stages of ontogenesis also leads to the production of offspring with a shorter period of passage of the phenophases "seedling-flowering" – "floweringmaturation" and a stable manifestation of signs that determine the quality of the fruits. Using only gametophytic selections and traditional methods of selection was less effective than alternating sporophyte-gametophyte ones.Conclusions. The differentiating ability of the selection methods used and their influence on obtaining more resistance and productive genotypes was established. The advantage of the method of step-by-step alternation of sporophyte-gametophyte selections, which led to the production of new lines (118/1, 124/1, 133-11/1, 133-12/1, 134/1, 110/1 and 7/1) with high resistance at different stages of ontogenesis (sporophyte-gametophyte), shorter vegetation period and high fruit-forming capacity in three different years of research (2015-2017).
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KITCH, L. W., O. BOUKAR, C. ENDONDO, and L. L. MURDOCK. "FARMER ACCEPTABILITY CRITERIA IN BREEDING COWPEA." Experimental Agriculture 34, no. 4 (October 1998): 475–86. http://dx.doi.org/10.1017/s0014479798004049.
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Cowpea (Vigna unguiculata) farmers from diverse geographical areas in northern Cameroon selected breeding lines from on-station trials for their own fields and explained their reasons (criteria) for making the selections. The average selection intensity employed by farmers varied from 6 to 17% and was similar to that employed by plant breeders. Their selection criteria fell into three broad categories relating to yield, preference and quality, and labour, which were very consistent over years, locations and gender. Selection criteria were strongly influenced by market preferences, reflecting the increasing role of cowpea as a cash crop. Implications of these findings for breeding strategies and genetic resource conservation are discussed.
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Zas, Rafael. "The impact of spatial heterogeneity on selection: a case study on Pinus pinaster breeding seedling orchards." Canadian Journal of Forest Research 38, no. 1 (January 2008): 114–24. http://dx.doi.org/10.1139/x07-099.
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Although failure to account for spatial autocorrelation has been dramatic in some forest progeny trials, little attention has been paid to how this issue may affect selections within the trials. The effects of spatial autocorrelation of height growth on the estimation of genetic gain and on the spatial distribution of the selected trees were studied in four Pinus pinaster Ait. progeny trials that were rogued using different selection methods and intensities. When selections are based on unadjusted original values, selected trees tend to be located in the best microsites and are unlikely to be the most genetically superior. This resulted in a loss of genetic gain that varied between 10% and 20% and sometimes exceeded 30%. Differences in the loss of gain among different selection methods and intensities were minor and followed no clear pattern. Selecting on the basis of a conventional model resulted in spatial patterns of the retained trees that were clearly aggregated in all cases. However, selections based on spatially adjusted data resulted in random spatial patterns, except with family selection because of the use of multiple-tree plots. Because clumping of the retained trees may seriously affect the quantity and quality of the seed crop, breeders are strongly encouraged to use appropriate spatial models for roguing breeding seedling orchards.
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Hiirsalmi, Heimo. "Small fruit breeding in Finland." Agricultural and Food Science 60, no. 4 (March 1, 1988): 223–34. http://dx.doi.org/10.23986/afsci.72295.
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In Finland, the breeding of small fruits has been focused on species belonging to the Ribes, Fragaria, Rubus, Vaccinium and Hippophaë genera. Of the blackcurrant, many local varieties have been brought under cultivation during this century, the most significant being ‘Brödtorp’ and ‘Melalahti’. The Department of Horticulture of the Agricultural Research Centre has, by means of intervariety crossings, developed selections combining high yield, upright growth and resistance to gooseberry mildew. A selection with greenberries, chosen from among the self-pollination progeny of the Swedish ‘Öjebyn’ variety, was released for cultivation in 1987, under the name ‘Vertti’. As to the gooseberry, the old Finnish varieties ‘Hinnnomäen keltainen’ and ‘Lepaanpunainen’ are still generally cultivated. In 1984, the Department of Horticulture released the late, cultivated strawberry variety ‘Hiku’, a very good cropper, for cultivation. It comes from the crossing ‘Senga Sengana’ x ‘Redgauntlet’. The most promising early selection, which this spring was released for cultivation under the name ‘Mari’, comes from the crossing ‘Pocahontas’ x ‘Lihama’. In 1986, the wood strawberry variety ‘Minja’ a result of the crossing Fragaria vesca x ‘Rügen’, was brought under cultivation. In the breeding of the raspberry, the Department of Horticulture has utilized the gene pools of wild raspberries; this has produced new selections with fairly good winter hardiness. This spring a variety named ‘Ville’, which was produced in the crossing of the Canadian ‘Ottawa’ and a Finnish wild raspberry strain, was introduced on the market. In addition, the raspberry has been crossed with the arctic bramble. By means of many crossings and back-crossings, the so-called nectar raspberry was developed, of which the variety ‘Heija’ was released for cultivation in 1975 and the variety ‘Heisa’ in 1981. Of the arctic bramble, two natural strains selected by the North Savo Research Station of the Agricultural Research Centre were brought under cultivation in 1972 under the variety names ‘Mesma’ and ‘Mespi’. The cross between them, ‘Pima’, was released for cultivation in 1982. By crossing the arctic bramble with the Alaska bramble, the Department of Horticulture has developed arctic bramble hybrid selections, two of which were named varieties, ‘Aura’ and ‘Astra’, in 1986. They form a higher growth structure than the arctic bramble, are better croppers and have bigger berries with the fine aroma of the arctic bramble. As a result of the breeding work done at the Department of Horticulture, a high bush blueberry variety, ‘Aron’, with a better winter hardiness than the foreign varieties, was released for cultivation in 1982. It comes from the back-crossing ‘Rancocas’ x (Vaccinium utiginosum x ‘Rancocas’). The aim of the breeding of the sea-buckthorn at the Department of Horticulture is, by means of crossings between subspecies growing wild in Europe and Asia, to reduce the thorniness of the bushes and to cause the berries to come off the stalks intact. The release of two selections for cultivation is presently being prepared.
Dissertations / Theses on the topic "Breeding selections"
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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
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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.
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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.
Books on the topic "Breeding selections"
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Bos, Izak. Selection methods in plant breeding. London: Chapman & Hall, 1995.
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Selection indices in plant breeding. Boca Raton, Fla: CRC Press, 1986.
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Bos, Izak, and Peter Caligari. Selection Methods in Plant Breeding. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-015-8432-6.
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Bos, Izak, and Peter Caligari. Selection Methods in Plant Breeding. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6370-1.
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Males, James Robert. Bull selection. Pullman: Cooperative Extension, College of Agriculture & Home Economics, Washington State University, 1988.
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Flauhaus, Günter. Dwarf rabbits: Selection, care, and breeding. Neptune City, NJ: T.F.H., 1985.
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Trygve, Gjedrem, and AKVAFORSK (Norway), eds. Selection and breeding programs in aquaculture. Dordrecht: Springer, 2005.
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Flauaus, Gunther. Dwarf rabbits: Selection, care and breeding. [S.l.]: Tfh, 1985.
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Gjedrem, Trygve, ed. Selection and Breeding Programs in Aquaculture. Berlin/Heidelberg: Springer-Verlag, 2005. http://dx.doi.org/10.1007/1-4020-3342-7.
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1941-, Weber Eberhard, ed. Quantitative genetics and selection in plant breeding. Berlin: W. de Gruyter, 1986.
Find full textBook chapters on the topic "Breeding selections"
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Robert, Pauline, Charlotte Brault, Renaud Rincent, and Vincent Segura. "Phenomic Selection: A New and Efficient Alternative to Genomic Selection." In Methods in Molecular Biology, 397–420. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2205-6_14.
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AbstractRecently, it has been proposed to switch molecular markers to near-infrared (NIR) spectra for inferring relationships between individuals and further performing phenomic selection (PS), analogous to genomic selection (GS). The PS concept is similar to genomic-like omics-based (GLOB) selection, in which molecular markers are replaced by endophenotypes, such as metabolites or transcript levels, except that the phenomic information obtained for instance by near-infrared spectroscopy (NIRS) has usually a much lower cost than other omics. Though NIRS has been routinely used in breeding for several decades, especially to deal with end-product quality traits, its use to predict other traits of interest and further make selections is new. Since the seminal paper on PS, several publications have advocated the use of spectral acquisition (including NIRS and hyperspectral imaging) in plant breeding towards PS, potentially providing a scope of what is possible. In the present chapter, we first come back to the concept of PS as originally proposed and provide a classification of selected papers related to the use of phenomics in breeding. We further provide a review of the selected literature concerning the type of technology used, the preprocessing of the spectra, and the statistical modeling to make predictions. We discuss the factors that likely affect the efficiency of PS and compare it to GS in terms of predictive ability. Finally, we propose several prospects for future work and application of PS in the context of plant breeding.
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Chevalier, M., and Y. Lespinasse. "Histological and cytological studies of the interaction between apple selections carrying the resistance Vm and compatible and incompatible Venturia inaequalis strains." In Developments in Plant Breeding, 87–92. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0467-8_18.
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Unêda-Trevisoli, Sandra Helena, Fabiana Mota da Silva, and Antonio Orlando Di Mauro. "Marker-Assisted Selection and Genomic Selection." In Soybean Breeding, 275–91. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-57433-2_14.
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Vello, Natal Antonio, and Felipe Maniero Nazato. "Recurrent Selection." In Soybean Breeding, 171–91. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-57433-2_10.
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Bhering, Leonardo Lopes, Leonardo de Azevedo Peixoto, and Cosme Damião Cruz. "Parental Selection." In Soybean Breeding, 131–47. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-57433-2_8.
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Arús, P., and J. Moreno-González. "Marker-assisted selection." In Plant Breeding, 314–31. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1524-7_20.
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Wenzel, G., and B. Foroughi-Wehr. "In vitro selection." In Plant Breeding, 353–70. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1524-7_22.
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Visscher, P. M., S. Van der Beek, and C. S. Haley. "Marker Assisted Selection." In Animal Breeding, 119–36. London: Routledge, 2021. http://dx.doi.org/10.1201/9781315137483-9.
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Ottaviano, E., and M. Sari-Gorla. "Gametophytic and sporophytic selection." In Plant Breeding, 332–52. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1524-7_21.
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Austin, R. B. "Augmenting yield-based selection." In Plant Breeding, 391–405. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1524-7_24.
Full textConference papers on the topic "Breeding selections"
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Grosser, Jude W. "The Role of Biotechnology in the Development of Improved Citrus Scion and Rootstock Cultivars." In ASME 1992 Citrus Engineering Conference. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/cec1992-3802.
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The development of improved citrus and scion rootstock cultivars has been limited by several factors, including complex reproductive biology, extended juvenility, and a lack of support and continuity of long-termed conventional breeding programs (Gmitter et al., 1991). Most commercially important scion and rootstock cultivars have arisen from the selection of bud-sport mutations within existing clones or by chance seedling selections. However, there are a few important scion and rootstock cultivars that were developed by conventional breeding. Such scion cultivars are mandarin hybrids developed by USDA breeders, primarily tangelos (mandarin x grapefruit hybrids) and tangors (mandarin x sweet orange hybrids) including ‘Minneola’, ‘Orlando’, ‘Nova’, ‘Page’, ‘Robinson’, ‘Fairchild’, ‘Sunburst’ (Saunt, 1990), and more recently ‘Fall Glo’ and ‘Ambersweet’ (C.J. Hearn, personal communication). Important rootstock cultivars developed by conventional breeding include Swingle citrumelo (grapefruit x trifoliate orange hybrid) and Carrizo and Troyer citranges (sweet orange x trifoliate orange hybrid). Because of renewed interest and the development of improved breeding parents, sexual hybridization will play an increasingly important role in citrus cultivar improvement. The integration of emerging biotechnologies with conventional breeding methods will facilitate and expedite citrus cultivar improvement. Paper published with permission.
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Sasco, Elena. "Efectele genetice implicate în răspunsul grăului comun la filtratul de cultură Drechslera sorokiniana (SACC.) subram." In VIIth International Scientific Conference “Genetics, Physiology and Plant Breeding”. Institute of Genetics, Physiology and Plant Protection, Republic of Moldova, 2021. http://dx.doi.org/10.53040/gppb7.2021.71.
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Helminthosporiosis caused by the fungus Drechslera sorokiniana (Sacc.) causes significant crop and quality losses to Triticum aestivum L. in agroecological conditions with extreme humidity. Increasing the resistance is considered the most cost-effective and sustainable approach to disease control. The aim of this study was to determine the genetic effects involved in the inheritance of resistance, using the ge-netic model of character reproduction in descendants of wheat. Generations F1, F2, BCP1 and BCP2, de-scended from the mutual crossing of the parents Basarabeanca / Moldova 30 and Moldova 30 / Moldova 3 (P1 and P2) were evaluated for the response of callus characters to the action of D. sorokiniana culture filtrate on the medium Murashige Skoog. Fungal metabolites have decreased the effects of gene actions and epistatic interactions, but also their variance. The phenomenon corresponds to the decrease of callus indices. A great importance for the heredity of the character of the surface of the callus manifested the epistatic effects of additive-dominant (ad) type. In the case of callus biomass comparable to the mean val-ues were the a actions, but also the ad and dd epistatic effects. The predominant involvement of epistatic effects indicates the need for resistance selections to helminthosporiosis in late generations of wheat.
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Пынтя, Мария. "Проявление монилиоза у некоторых генотипов абрикоса в условиях Республики Молдова." In International Scientific Symposium "Plant Protection – Achievements and Prospects". Institute of Genetics, Physiology and Plant Protection, Republic of Moldova, 2020. http://dx.doi.org/10.53040/9789975347204.17.
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In the paper there are presented results of investigations concerning the susceptibility to blossom blight (Monilinia laxa) of 120 apricot varieties and selections introduced from different ecologo-geografic zones in pedo-climatical conditions of Сentral pomological zone of Republic of Мoldova being compared with local ones. A high manifestation of susceptibility to this pathogen where observed on some genotypes introduced from France, Italy, Canada. Some promising varieties for utilization in the future apricot breeding and genetics programs regarding creation of genotypes resistant to Monilinia laxa have been emphasized.
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Timoshenko, I. V., and N. V. Geraskina. "Varieties of redis breeding Biryuchekutskaya Vegetable Breeding Experimental Station." In Растениеводство и луговодство. Тимирязевская сельскохозяйственная академия, 2020. http://dx.doi.org/10.26897/978-5-9675-1762-4-2020-63.
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Radish is of great importance as an early valuable vegetable product, especially in spring and first half of summer. Due to its high taste and nutritional qualities, radish is the most popular early crop in the world practice of vegetable growing, which is grown everywhere. One of the main methods for solving the problem of providing the population of our country with marketable products of this culture is the development of selection and seed production. The creation of new competitive varieties and hybrids will help to transfer the vegetable growing industry to a qualitatively new level of development.
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Pugacheva, I. G. "Experience of microgametophyte selection in tomato breeding." In CURRENT STATE, PROBLEMS AND PROSPECTS OF THE DEVELOPMENT OF AGRARIAN SCIENCE. Federal State Budget Scientific Institution “Research Institute of Agriculture of Crimea”, 2019. http://dx.doi.org/10.33952/09.09.2019.92.
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Mirskaya, Galina, N. Rushina, N. Sinyavina, A. Kochetov, and Yuriy Chesnokov. "Using insensitive PPD-D1a allele for the early forms selection of bread wheat in the initial selection stages." In VIIth International Scientific Conference “Genetics, Physiology and Plant Breeding”. Institute of Genetics, Physiology and Plant Protection, Republic of Moldova, 2021. http://dx.doi.org/10.53040/gppb7.2021.42.
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Determination the photoperiod-insensitive allele (Ppd-D1a) in wheat cultivars is necessary for use in breeding development of newly wheat cultivars. The aim of our study was to select breeding material by screening Ppd-D1 gene alleles and estimation value and the degree of heterosis in F1. Using these two methods, it is possible to select genetic material for increased breeding of new wheat lines that combine earliness and increased productivity. In this study 26 varieties of spring soft wheat were screened for the Ppd-D1 gene alleles. The Ppd-D1a allele was detected in 12 wheat varieties (ITMI 10, 29, 47, 57, 58, 59, 60, 89, 94, AFI-91, AFI-177, Opata 85), the recessive Ppd-D1b allele was detected in 14 wheat varieties (ITMI 7, 31, 32, 44, 80, 88, 83, 115, Zlata, Lisa, Agata, Lubava, W7984). Based on the results of a comprehensive assessment, parental pairs were chosen and 10 recombinants were obtained. Based on estimation value and the degree of heterosis of the main ear traits in F1, such as "ear length", "number of grains from the ear" and "weight of grains from the ear" were identified 4 crosses as initial to create wheat cultivars that combine earliness and increased productivity.
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Marinich, Mihail. "SELECTION EVALUATION OF THE SOURCE MATERIAL OF FESTUCA RUBRA L. OF THE LAWN DIRECTION." In Multifunctional adaptive fodder production 26 (74). ru: Federal Williams Research Center of Forage Production and Agroecology, 2021. http://dx.doi.org/10.33814/mak-2021-26-74-51-59.
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The aim of the research was to assess the breeding value of the source material of F. rubra of the lawn direction obtained under conditions of various ecotopes of the south of the Central Russian Upland with a predominance of carbonate substrate. In total, 106 numbers of red fescue of various genetic and geological-geographical origin were evaluated in the experiment: 4 varieties and 102 breeding samples. Tests of the breeding value of the collection numbers were carried out in comparison with the zoned varieties of domestic selection (‘Veselka’, ‘Gostenka’, ‘Iskrinka’) and foreign selection (‘Gondolin’). The forms of F. rubra have been identified, approaching erect in shape, having a high shoot-forming ability, pronounced antocian color of inflorescences, whitish bloom on the leaves, which increases the overall decorative effect of lawn herbage. According to a number of important traits for breeding for seed productivity, the forms selected in natural habitats with a predominance of carbonate substrate have wide limits of variation and can serve as genetic sources of individual breeding traits for obtaining new varieties of lawn management with high seed productivity and decorativeness.
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Ferreira, Ana Paula Lüdtke. "On the problem of compensatory mating in animal breeding." In Workshop-Escola de Informática Teórica. Sociedade Brasileira de Computação, 2021. http://dx.doi.org/10.5753/weit.2021.18928.
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Animal breeding relies on two processes to achieve its objectives: the selection and the mating systems. Mating systems devise a particular plan to perform one or more breeding goals, which often encompass improving the herd's health and maximising financial gains in animal production systems. Compensatory mating is a strategy to produce animals with more homogeneous selection trait characteristics, discarding the production of exceptional animals in favour of a more balanced herd. This paper defines and investigates the complexity class of the optimal compensatory mating problem, proving that a polynomial-time algorithm can solve it.
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Kibalnik, O. P., and T. V. Larina. "STUDY OF THE SOURCE MATERIAL FOR THE SELECTION OF HIGH-SUGAR VARIETIES OF SUGAR SORGHUM." In Agrobiotechnology-2021. Publishing house RGAU-MSHA, 2021. http://dx.doi.org/10.26897/978-5-9675-1855-3-2021-99.
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Currently, the development of the selection of sugar sorghum to increase the content of water-soluble sugars in the juice of the stem is relevant. The varieties and promising lines of sorghum breeding of the Institute, collectible cultivars as producers of sugars for use as a starting material for further breeding have been identified.
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Салтанович, Татьяна, Людмила Анточ, and А. Дончилэ. "Оценка реакции мужского гаметофита томата на действие патогенов Alternaria Spp." In International Scientific Symposium "Plant Protection – Achievements and Prospects". Institute of Genetics, Physiology and Plant Protection, Republic of Moldova, 2020. http://dx.doi.org/10.53040/9789975347204.84.
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Research objective: to identify tomato genotypes resistant to Alternaria on variability and symptoms of male gametophyte on selective backgrounds with cultural filtrate of pathogens Alternaria spp. A set of gamete breeding techniques and genetic-statistical analysis were used in the experiments. Some patterns of the variability and heritability of traits in the tomato male gametophyte have been identified on media with filtrates of pathogens. The differences in the resistance of pollen to the filtrate influence were established; the differentiation and selection of genotypes for further breeding were made. These studies can be used at different stages of the selection process.
Reports on the topic "Breeding selections"
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Taliaferro, C. M. Breeding and Selection of New Switchgrass Varieties for Increased Biomass Production. Office of Scientific and Technical Information (OSTI), May 2003. http://dx.doi.org/10.2172/814564.
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Juvik, John A., Avri Bar Zur, and Torbert R. Rocheford. Breeding for Quality in Vegetable Maize Using Linked Molecular Markers. United States Department of Agriculture, January 1993. http://dx.doi.org/10.32747/1993.7568764.bard.
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Recently, the vegetable corn industry has shifted from the use of traditional cultivars with the sugary1 (su1) endosperm mutation to newer hybrids homozygous for the shrunken2 (sh2) or sugary enhancer1 (se1) genes. With greater kernel sucrose content, these hybrids are preferred by consumers and retain sugar for longer post harvest periods, providing the industry with more time to marker products with superior quality. Commercialization has been hindered, however, by reduced field emergence, and the establishment of stands with heterogeneous uniformity and maturities. This investigation was conducted to identify key biochemical and physiological characteristics in sh2 and se1 maize kernels associated with improved emergence, and stand establishment; and in immature ears at fresh harvest maturity, properties associated with eating quality. The location of genes or QTL controlling these kernel characteristics and other traits were then mapped to specific chromosomal regions by their linkage to molecular markers using two segregating F2:3 populations. This database was used to compare the efficiency of marker-assisted selection of key alleles with phenotypic selection for trait improvement. A model designed to uncover and quantify digenic interaction was applied to the datasets to evaluate the role of epistasis in the inheritance of quantitative traits.
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Behrends, Leslie L., Gideon Hulata, J. B. Kingsley, and Giora Wohlfarth. Breeding Fast Growing Red Tilapias with Improved Cold Tolerance by Introgression and Selection. United States Department of Agriculture, August 1987. http://dx.doi.org/10.32747/1987.7566867.bard.
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Ivanov, R. V. History of creation of megezheksky breed of horses, the current state. Selection and breeding. ООО «Информационно-консалтинговый центр», 2019. http://dx.doi.org/10.18411/konevodstvo.2019..15rus.
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Dunham, Rex A., Boaz Moav, Thomas Chen, and Benzion Cavari. Expression and Inheritance of Growth Hormone Gene Constructs and Selective Breeding of Transgenic Farmed Fish. United States Department of Agriculture, August 1994. http://dx.doi.org/10.32747/1994.7568774.bard.
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Objectives: To accomplish stable expression, inheritance of transgenes and growth improvement in transgenic channel catfish, Ictalurus punctatus, and common carp, Cyprinus carpio, containing growth hormone (GH) genes, develop transgenic fish with all fish constructs, determine the relationships between copy number, expression and growth, determine the combined affect of selective breeding and gene transfer and assess environmental risk of transgenic fish. To develop mechanisms of triploidization for transgenic carp. Results: Performance of transgenic channel catfish was made uniform by selection. Growth of channel catfish and common carp was improved 40-50% more by combining gene transfer of GH genes with selection and crossbreeding than with either selection of crossbreeding. Growth improvement of transgenic catfish was not strongly correlated with copy number and expression levels. Progress was made in producting triploid transgenic common carp. Insertion of salmonid GH gene did not alter reproductive performance in channel catfish. Transgenic channel catfish grew no faster than controls when they had to forage on natural food and transgenic individuals were slightly more vulnerable to predation indicating that fitness of transgenic individuals in natural conditions is less than or equal to non-transgenic channel catfish. Contribution to Agriculture: These experiments are the first to demonstrate that transgenic fish can increase aquaculture production in the aquaculture production in the aquaculture environment. This research also demonstrated that maximum benefit of gene transfer in farmed fish is attained when combined with traditional selective breeding.
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Levy, Avraham, Clifford Weil, and Wojtek Pawlowski. Enhancing the Rate of Meiotic Crossing-Over for Plant Breeding. United States Department of Agriculture, January 2009. http://dx.doi.org/10.32747/2009.7696532.bard.
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Meiotic recombination contributes to the generation of biodiversity as well as to genome stability, ensuring the proper segregation of homo logs during meiosis. It is also an essential step in the process of plant breeding. It generates the diversity needed by the breeder for selection of novel varieties. In this project, we have collaborated towards the goals to identify and characterize key genes involved in meiotic recombination. In addition we have shown how some of these genes can be used, through loss of function, or through overexpression, to enhance homologous recombination in Arabidopsis and in maize. Our main achievements can be summarized as follows: 1- To establish a collection of mutants, in Arabidopsis and in maize for candidate genes. In Arabidopsis, insertion mutants were isolated in the following genes: AtMSHI, AtMSH4, AtMSH5, AtMLH3, AtPHSl, and mutants in the Mre11/Rad50/Nbs1 complex. In maize, the TILLING system was established and enabled to isolate mutants in candidate genes, such as Rad2l-4a, Sgo2, and Aml. In addition, we generated phs 1 mutant alleles as well as mutants in the Mre11/Rad50/Nbs1 complex. No mus8l mutants have been found thus far. 2- We showed that mutants in AtMLH3 have decreased rates of crossover, suggesting that overexpression of these genes may enhance crossover. Mutants in AtMSHlhad no effect and mutants in AtMSH4 and 5 showed sterility. Overexpression of these genes might also enhance crossover. The effect of other mutations on crossovers in maize is still being investigated. 3- We showed that overexpression of AtMLH1, RecG and RuvC under a meioticspecific promoter enhances meiotic crossover in Arabidopsis. The effect of PHSloverexpression on crossover is expected to be determined soon. 4- New tools have been developed and perfected to study the recombination genes effect on meiotic crossovers. This includes antibodies, cDNAs and fusion proteins.
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Blum, Abraham, and Henry T. Nguyen. Molecular Tagging of Drought Resistance in Wheat: Osmotic Adjustment and Plant Productivity. United States Department of Agriculture, November 2002. http://dx.doi.org/10.32747/2002.7580672.bard.
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Drought stress is a major limitation to bread wheat (Triticumaestivum L.) productivity and its yield stability in arid and semi-arid regions of world including parts of Israel and the U.S. Currently, breeding for sustained yields under drought stress is totally dependent on the use of yield and several key physiological attributes as selection indices. The attempt to identify the optimal genotype by evaluating the phenotype is undermining progress in such breeding programs. Osmotic adjustment (OA) is an effective drought resistance mechanism in many crop plants. Evidence exists that there is a genetic variation for OA in wheat and that high OA capacity supports wheat yields under drought stress. The major objective of this research was to identify molecular markers (RFLPs, restriction fragment length polymorphisms; and AFLPs, amplified fragment length polymorph isms) linked to OA as a major attribute of drought resistance in wheat and thus to facilitate marker-assisted selection for drought resistance. We identified high and low OA lines of wheat and from their cross developed recombinant inbred lines (RILs) used in the molecular tagging of OA in relation to drought resistance in terms of plant production under stress. The significant positive co-segregation of OA, plant water status and yield under stress in this RIL population provided strong support for the important role of OA as a drought resistance mechanism sustaining wheat production under drought stress. This evidence was obtained in addition to the initial study of parental materials for constructing this RIL population, which also gave evidence for a strong correlation between OA and grain yield under stress. This research therefore provides conclusive evidence on the important role of OA in sustaining wheat yield under drought stress. The measurement of OA is difficult and the selection for drought resistance by the phenotypic expression of OA is practically impossible. This research provided information on the genetic basis of OA in wheat in relations to yield under stress. It provided the basic information to indicate that molecular marker assisted selection for OA in wheat is possible. The RIL population has been created by a cross between two agronomic spring wheat lines and the high OA recombinants in this population presented very high OA values, not commonly observed in wheat. These recombinants are therefore an immediate valuable genetic recourse for breeding well-adapted drought resistant wheat in Texas and Israel. We feel that this work taken as a whole eliminate the few previous speculated . doubts about the practical role of OA as an important mechanism of drought resistance in economic crop plants. As such it should open the way, in terms of both concept and the use of marker assisted selection, for improving drought resistance in wheat by deploying high osmotic adjustment.
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Weller, Joel I., Ignacy Misztal, and Micha Ron. Optimization of methodology for genomic selection of moderate and large dairy cattle populations. United States Department of Agriculture, March 2015. http://dx.doi.org/10.32747/2015.7594404.bard.
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The main objectives of this research was to detect the specific polymorphisms responsible for observed quantitative trait loci and develop optimal strategies for genomic evaluations and selection for moderate (Israel) and large (US) dairy cattle populations. A joint evaluation using all phenotypic, pedigree, and genomic data is the optimal strategy. The specific objectives were: 1) to apply strategies for determination of the causative polymorphisms based on the “a posteriori granddaughter design” (APGD), 2) to develop methods to derive unbiased estimates of gene effects derived from SNP chips analyses, 3) to derive optimal single-stage methods to estimate breeding values of animals based on marker, phenotypic and pedigree data, 4) to extend these methods to multi-trait genetic evaluations and 5) to evaluate the results of long-term genomic selection, as compared to traditional selection. Nearly all of these objectives were met. The major achievements were: The APGD and the modified granddaughter designs were applied to the US Holstein population, and regions harboring segregating quantitative trait loci (QTL) were identified for all economic traits of interest. The APGD was able to find segregating QTL for all the economic traits analyzed, and confidence intervals for QTL location ranged from ~5 to 35 million base pairs. Genomic estimated breeding values (GEBV) for milk production traits in the Israeli Holstein population were computed by the single-step method and compared to results for the two-step method. The single-step method was extended to derive GEBV for multi-parity evaluation. Long-term analysis of genomic selection demonstrated that inclusion of pedigree data from previous generations may result in less accurate GEBV. Major conclusions are: Predictions using single-step genomic best linear unbiased prediction (GBLUP) were the least biased, and that method appears to be the best tool for genomic evaluation of a small population, as it automatically accounts for parental index and allows for inclusion of female genomic information without additional steps. None of the methods applied to the Israeli Holstein population were able to derive GEBV for young bulls that were significantly better than parent averages. Thus we confirm previous studies that the main limiting factor for the accuracy of GEBV is the number of bulls with genotypes and progeny tests. Although 36 of the grandsires included in the APGD were genotyped for the BovineHDBeadChip, which includes 777,000 SNPs, we were not able to determine the causative polymorphism for any of the detected QTL. The number of valid unique markers on the BovineHDBeadChip is not sufficient for a reasonable probability to find the causative polymorphisms. Complete resequencing of the genome of approximately 50 bulls will be required, but this could not be accomplished within the framework of the current project due to funding constraints. Inclusion of pedigree data from older generations in the derivation of GEBV may result is less accurate evaluations.
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Rine, Kristin, Roger Christopherson, and Jason Ransom. Harlequin duck (Histrionicus histrionicus) occurrence and habitat selection in North Cascades National Park Service Complex, Washington. National Park Service, April 2022. http://dx.doi.org/10.36967/nrr-2293127.
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Harlequin ducks (Histrionicus histrionicus) are sea ducks that migrate inland each spring to nest along fast-flowing mountain streams. They are considered one of the most imperiled duck species in North America and occur in two distinct populations on the Atlantic and Pacific coasts. The Pacific coast population includes Washington State, where harlequin ducks breed in the Olympic, Cascade, and Selkirk Mountains. This species is designated as a Management Priority Species by the National Park Service within North Cascades National Park Service Complex (NOCA). This report summarizes harlequin duck surveys conducted during 15 years across a 27-year period (1990 and 2017) on major streams within NOCA, and incidental observations collected from 1968–2021. The primary objectives of these surveys were to 1) document the distribution and abundance of harlequin duck observations within NOCA boundaries, 2) describe productivity (number of broods and brood size), 3) describe breeding chronology of harlequin ducks, and 4) describe habitat characteristics of breeding streams. Sixty-eight stream surveys over 15 years resulted in observations of 623 individual harlequin ducks comprising various demographics, including single adults, pairs, and broods. In addition, we collected 184 incidental observations of harlequin ducks from visitors and staff between 1968–2021. Harlequin ducks were observed on 22 separate second- to sixth-order streams throughout NOCA across the entire 53-year span of data, both incidentally and during harlequin duck surveys by Park staff. Harlequin ducks were detected on 8 of the 13 streams that were actively surveyed. Excluding recounts, 88.7% (n = 330) of individual harlequin duck observations during surveys occurred in the Stehekin River drainage. Between all surveys and incidental observations, 135 unpaired females without broods were sighted across all NOCA waterways. Thirty-nine broods were recorded between NOCA surveys and incidental observations, with a mean brood size of 3.61 (± 1.44 SD; range = 2–10). Breeding pairs were recorded as early as April 5 and were seen on streams until June 15, a period of less than seven weeks (median: May 2), but most pairs were observed within a 3-week span, between April 26 and May 17. Single females (unpaired with a male, with (an)other female(s), or with a brood) were observed on streams between April 26 and August 25 (median: July 3), though most observations were made within a 5-week period between June 12 and July 19. Habitat data collected at adult harlequin duck observation sites indicate that the birds often used stream reaches with features that are characteristic of high-energy running water. While adults occupied all instream habitat types identified, non-braided rapids and riffles were used most frequently, followed by pools and backwaters. Larger instream substrate sizes (cobbles and boulders) were present at most observation sites. Adult harlequin ducks were more often found at locations that lacked visible drifting or lodged woody debris, but drift debris was a slightly more abundant debris type. The presence of gravel bars and at least one loafing site was common. Adult harlequin ducks were more often observed in association with vegetation that offered some cover over the channel, but not where banks were undercut. The average channel width at adult observation sites was 34.0 m (range: 6-80 m; n = 114) and 27.6 m (± 15.7 m; range: 10-60 m; n = 12) at brood observation sites. Compared to adult harlequin duck sites, broods were observed more frequently in low velocity habitat (pools, backwaters), but rarely in rapids. Cobble and boulder substrates were still the most dominant substrate type. Contrary to adult ducks, broods were observed most often observed in meandering stream channels, a morphology indicative of low gradient, low velocity stream reaches. Most broods were observed in stream reaches with gravel bars, loafing sites, and...
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Malkinson, Mertyn, Irit Davidson, Moshe Kotler, and Richard L. Witter. Epidemiology of Avian Leukosis Virus-subtype J Infection in Broiler Breeder Flocks of Poultry and its Eradication from Pedigree Breeding Stock. United States Department of Agriculture, March 2003. http://dx.doi.org/10.32747/2003.7586459.bard.
Full textAbstract:
Objectives 1. Establish diagnostic procedures to identify tolerant carrier birds based on a) Isolation of ALV-J from blood, b) Detection of group-specific antigen in cloacal swabs and egg albumen. Application of these procedures to broiler breeder flocks with the purpose of removing virus positive birds from the breeding program. 2. Survey the AL V-J infection status of foundation lines to estimate the feasibility of the eradication program 3. Investigate virus transmission through the embryonated egg (vertical) and between chicks in the early post-hatch period (horizontal). Establish a model for limiting horizontal spread by analyzing parameters operative in the hatchery and brooder house. 4. Compare the pathogenicity of AL V-J isolates for broiler chickens. 5. Determine whether AL V-J poses a human health hazard by examining its replication in mammalian and human cells. Revisions. The: eradication objective had to be terminated in the second year following the closing down of the Poultry Breeders Union (PBU) in Israel. This meant that their foundation flocks ceased to be available for selection. Instead, the following topics were investigated: a) Comparison of commercial breeding flocks with and without myeloid leukosis (matched controls) for viremia and serum antibody levels. b) Pathogenicity of Israeli isolates for turkey poults. c) Improvement of a diagnostic ELISA kit for measuring ALV-J antibodies Background. ALV-J, a novel subgroup of the avian leukosis virus family, was first isolated in 1988 from broiler breeders presenting myeloid leukosis (ML). The extent of its spread among commercial breeding flocks was not appreciated until the disease appeared in the USA in 1994 when it affected several major breeding companies almost simultaneously. In Israel, ML was diagnosed in 1996 and was traced to grandparent flocks imported in 1994-5, and by 1997-8, ML was present in one third of the commercial breeding flocks It was then realized that ALV-J transmission was following a similar pattern to that of other exogenous ALVs but because of its unusual genetic composition, the virus was able to establish an extended tolerant state in infected birds. Although losses from ML in affected flocks were somewhat higher than normal, both immunosuppression and depressed growth rates were encountered in affected broiler flocks and affected their profitability. Conclusions. As a result of the contraction in the number of international primary broiler breeders and exchange of male and female lines among them, ALV-J contamination of broiler breeder flocks affected the broiler industry worldwide within a short time span. The Israeli national breeding company (PBU) played out this scenario and presented us with an opportunity to apply existing information to contain the virus. This BARD project, based on the Israeli experience and with the aid of the ADOL collaborative effort, has managed to offer solutions for identifying and eliminating infected birds based on exhaustive virological and serological tests. The analysis of factors that determine the efficiency of horizontal transmission of virus in the hatchery resulted in the workable solution of raising young chicks in small groups through the brooder period. These results were made available to primary breeders as a strategy for reducing viral transmission. Based on phylogenetic analysis of selected Israeli ALV-J isolates, these could be divided into two groups that reflected the countries of origin of the grandparent stock. Implications. The availability of a simple and reliable means of screening day old chicks for vertical transmission is highly desirable in countries that rely on imported breeding stock for their broiler industry. The possibility that AL V-J may be transmitted to human consumers of broiler meat was discounted experimentally.