Opportunities for breeding for disease resistance in British sheep

2005 ◽  
Vol 2005 ◽  
pp. 49-49
Author(s):  
G.J. Nieuwhof ◽  
S.C. Bishop
Keyword(s):  
Disease Resistance ◽  
Disease Incidence ◽  
Selection Index ◽  
Economic Values ◽  
Sheep Breeding ◽  
Sheep Scab ◽  
Internal Parasites ◽  
Breeding Schemes

Recently, the costs of eight sheep diseases were calculated by Bennett and IJpelaar (2003). The highest annual costs were estimated for enzootic abortions in ewes (EAE) £20 M and toxoplasmosis £12M. In a survey among its members, the Moredun Foundation (1997) identified internal parasites (GI parasites), sheep scab and footrot as the most important sheep diseases, but these three diseases were not analysed by Bennett and IJpelaar (2003). The aim of this study is to estimate the benefits of reductions in the incidence or severity of these diseases, using the methodology of Bennett et al. (1999), and the benefits of reductions in disease incidence or severity. From this, marginal economic values for resistance are calculated and applied in selection index scenarios that mimic current sheep breeding schemes.

Application of a multiple-trait animal model for genetic evaluation of maternal and lamb traits in Norwegian sheep

1995 ◽  
Vol 60 (3) ◽  
pp. 457-469 ◽  
Author(s):  
I. Olesen ◽  
M. Svendsen ◽  
G. Klemetsdal ◽  
T. A. Steine
Keyword(s):  
Animal Model ◽  
Selection Index ◽  
Computer Programs ◽  
Genetic Evaluation ◽  
Genetic Change ◽  
Memory Requirement ◽  
Multiple Trait ◽  
Economic Values ◽  
Sheep Breeding ◽  
Fleece Weight

AbstractA selection index for overall economic merit and five subindexes for maternal and lamb traits were constructed. For estimation of breeding values, two computer programs were developed. A multiple-trait animal model was programmed for the ewe traits including number of lambs born ofl-, 2- and 3-years-old ewes and ewe fleece weight of yearlings. In order to reduce the memory requirement, the lamb data (growth rate, carcass weight, carcass grade, fat% and lamb fleece iveight) were analysed by a reduced multiple-trait animal model including genetic maternal effect. Experiences with the computer programs in genetic evaluation of approximately 619 000 animals are presented. It is concluded that the models and computing strategy may be used for genetic evaluation in the national sheep breeding programme in Norway.Relative economic values for all traits were derived from a profit equation on a 3-year-old ewe basis. The sensitivity towards changed economic values urns found to be low. Further, the genetic change in the ewe traits of the Norwegian breeds has been estimated, and a significant improvement was found, which was two to four times higher in the ram circles than outside. For breeding rams, the genetic change for number of lambs born was estimated to be approximately 0·01 lambs per ewe and year.

scholarly journals Field Evaluations of Leaf Spot Resistance and Yield in Peanut Genotypes in the United States and Bolivia

Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 263-268 ◽  
Author(s):  
S. K. Gremillion ◽  
A. K. Culbreath ◽  
D. W. Gorbet ◽  
B. G. Mullinix ◽  
R. N. Pittman ◽  
...  
Keyword(s):  
United States ◽  
Disease Resistance ◽  
Leaf Spot ◽  
Field Experiments ◽  
Disease Incidence ◽  
The United States ◽  
Yield Potential ◽  
Cercospora Arachidicola ◽  
Breeding Lines ◽  
Progress Curve

Field experiments were conducted in 2002 to 2006 to characterize yield potential and disease resistance in the Bolivian landrace peanut (Arachis hypogaea) cv. Bayo Grande, and breeding lines developed from crosses of Bayo Grande and U.S. cv. Florida MDR-98. Diseases of interest included early leaf spot, caused by the fungus Cercospora arachidicola, and late leaf spot, caused by the fungus Cercosporidium personatum. Bayo Grande, MDR-98, and three breeding lines, along with U.S. cvs. C-99R and Georgia Green, were included in split-plot field experiments in six locations across the United States and Bolivia. Whole-plot treatments consisted of two tebuconazole applications and a nontreated control. Genotypes were the subplot treatments. Area under the disease progress curve (AUDPC) for percent defoliation due to leaf spot was lower for Bayo Grande and all breeding lines than for Georgia Green at all U.S. locations across years. AUDPC for disease incidence from one U.S. location indicated similar results. Severity of leaf spot epidemics and relative effects of the genotypes were less consistent in the Bolivian experiments. In Bolivia, there were no indications of greater levels of disease resistance in any of the breeding lines than in Bayo Grande. In the United States, yields of Bayo Grande and the breeding lines were greater than those of the other genotypes in 1 of 2 years. In Bolivia, low disease intensity resulted in the highest yields in Georgia Green, while high disease intensity resulted in comparable yields among the breeding lines, MDR-98, and C-99R. Leaf spot suppression by tebuconazole was greater in Bolivia than in the United States. This result indicates a possible higher level of fungicide resistance in the U.S. population of leaf spot pathogens. Overall, data from this study suggest that Bayo Grande and the breeding lines may be desirable germplasm for U.S. and Bolivian breeding programs or production.

scholarly journals Claw health and feed efficiency as new selection criteria in the Czech Holstein cattle Krupová Z., Wolfová M., Krupa E., Přibyl J., Zavadilová L.

2018 ◽  
Vol 63 (No. 10) ◽  
pp. 408-418 ◽  
Author(s):  
Z. Krupová ◽  
M. Wolfová ◽  
E. Krupa ◽  
J. Přibyl ◽  
L. Zavadilová
Keyword(s):  
Feed Intake ◽  
Feed Efficiency ◽  
Disease Incidence ◽  
Selection Index ◽  
Residual Feed Intake ◽  
Selection Response ◽  
Holstein Cattle ◽  
Breeding Objective ◽  
Economic Weights ◽  
The Impact

The objective of this study was to calculate economic weights for ten current breeding objective traits and for four new traits characterising claw health and feed efficiency in Czech Holstein cattle and to investigate the impact of different selection indices on the genetic responses for these traits. Economic weights were estimated using a bio-economic model, while applying actual (2017) and predicted (2025) production and economic circumstances. For the actual situation, the economic weights of claw disease incidence were –100.1 € per case, and those of daily residual feed intake in cows, breeding heifers, and fattened animals were –79.37, –37.16, and –6.33 €/kg dry matter intake per day, respectively. In the predicted situation, the marginal economic weights for claw disease and feed efficiency traits increased on average by 38% and 20%, respectively. The new traits, claw disease incidence and daily residual feed intake, were gradually added to the 17 current Holstein selection index traits to improve the new traits. Constructing a comprehensive index with 21 traits and applying the general principles of the selection index theory, a favourable annual genetic selection response was obtained for the new traits (–0.008 cases of claw disease incidence and –0.006 kg of daily residual feed intake across all cattle categories), keeping the annual selection response of the most important current breeding objective traits at a satisfactory level (e.g., 73 kg of milk yield per lactation, 0.016% of milk fat). Claw health and feed efficiency should be defined as new breeding objectives and new selection index traits of local dairy population.

scholarly journals Stochastic simulation of sheep breeding schemes for Iceland, with a focus on ewe trait improvement

2020 ◽  
Vol 2020 ◽  
pp. 25-33
Author(s):  
Eyjólfur Ingvi Bjarnason ◽  
Leiv Sigbjørn Eikje ◽  
Gunnar Klemetsdal
Keyword(s):  
Stochastic Simulation ◽  
Sheep Breeding ◽  
Trait Improvement ◽  
Breeding Schemes

scholarly journals Deriving economic values for national sheep breeding objectives using a bio-economic model

2019 ◽  
Vol 227 ◽  
pp. 44-54 ◽  
Author(s):  
A. Bohan ◽  
L. Shalloo ◽  
P. Creighton ◽  
D.P. Berry ◽  
T.M. Boland ◽  
...  
Keyword(s):  
Economic Model ◽  
Economic Values ◽  
Sheep Breeding ◽  
Breeding Objectives

Genetic analysis of Okra Yellow Vein Mosaic Virus disease resistance in wild relative of okra Abelmoschus angulosus Wall. ex Wight & Arn

2019 ◽  
Vol 17 (04) ◽  
pp. 346-351
Author(s):  
SamanthiKumari Wasala ◽  
Sumudu I. Senevirathne ◽  
Jayantha Bandara Senanayake ◽  
Anuradini Navoditha
Keyword(s):  
Disease Resistance ◽  
Mosaic Virus ◽  
Disease Severity ◽  
Virus Disease ◽  
Disease Incidence ◽  
Severity Index ◽  
Yellow Vein ◽  
Wild Relative ◽  
Yellow Vein Mosaic Virus ◽  
Progress Curve

AbstractWild relative of okra, Abelmoschus angulosus Wall. ex Wight & Arn. was identified as a resistant germplasm for Okra Yellow Vein Mosaic Virus (OYVMV) which is the devastating disease for okra cultivation in Sri Lanka. The mode of resistance of OYVMV in A. angulosus was studied with the aim of tagging responsible genes for the disease resistance. Wide hybridization was performed between A. angulosus and highly virus susceptible A. esculentus variety, MI-7. Very poor seed setting was observed in F1 and F2 generations due to post zygotic abortion. Disease screening was carried out using F1 and F2:3 populations along with parents in the field under induced disease pressure. Disease severity index and area under disease progress curve were calculated to measure disease severity. Number of genes segregating for OYVMV disease resistance was calculated for the F2:3 generation. Modified Wright's formula was used to estimate the effective gene number and mode of inheritance by a quantitative method. A χ2 test was performed for qualitative analysis. Plants of A. angulosus were totally free of virus incidence while 100% disease incidence was observed in the variety MI-7. F2:3 population showed between and within progeny segregation for disease incidence. Results indicated that the disease susceptibility was dominant over resistance. χ2 analysis revealed that the segregation of disease severity was significantly fit to the gene model of 9:6:1 (χ2 = 0.1757 at P ≤ 0.05) suggesting the disease resistance in A. angulosus is governing by two recessive genes in an additive manner. Result was confirmed by the quantitative analysis.

scholarly journals Molecular mapping of qBK1Z, a major QTL for bakanae disease resistance in rice

2020 ◽  
Author(s):  
Sais-Beul Lee ◽  
Namgyu Kim ◽  
Sumin Jo ◽  
Yeon-Jae Hur ◽  
Ji-youn Lee ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Molecular Mapping ◽  
Disease Incidence ◽  
Recombinant Inbred Lines ◽  
Rice Variety ◽  
Gibberella Fujikuroi ◽  
Chromosome 1 ◽  
Resistant Variety ◽  
Fusarium Fujikuroi ◽  
Bakanae Disease

AbstractBakanae disease is a fungal disease of rice (Oryza sativa L.) caused by the pathogen Gibberella fujikuroi (also known as Fusarium fujikuroi). Recently the disease incidence has increased in several Asian countries and continues to spread throughout the world. No rice varieties have been developed yet to be completely resistant to this disease. With increasing need to identify various genetic resources to impart resistance to local elite varieties, this study was carried out to identify novel quantitative trait loci (QTLs) from an indica variety Zenith. We performed a QTL mapping using 180 F2:9 recombinant inbred lines (RILs) derived from a cross between the resistant variety, Zenith, and the susceptible variety, Ilpum. A primary QTL study using the genotypes and phenotypes of the RILs indicated that the locus qBK1z conferring bakanae disease resistance from the Zenith was located in a 2.8 Mb region bordered by the two SSR markers, RM1331 and RM3530 on chromosome 1.The log of odds (LOD) score of qBK1z was 13.43, accounting for 30.9% of the total phenotypic variation. A finer localization of qBK1z was delimited at an approximate 730 kb interval in the physical map between Chr01_1435908 (1.43 Mbp) and RM10116 (2.16 Mbp). The development of a rice variety with a higher level of resistance against bakanae disease is a major challenge in many rice growing countries. Introducing qBK1z or pyramiding with other previously identified QTLs could provide effective genetic control of bakanae disease in rice.

The use of product traits such as lean growth rate as selection criteria in animal breeding

1987 ◽  
Vol 45 (2) ◽  
pp. 307-316 ◽  
Author(s):  
G. Simm ◽  
C. Smith ◽  
R. Thompson
Keyword(s):  
Growth Rate ◽  
Selection Criteria ◽  
Genetic Parameters ◽  
Selection Index ◽  
Genetic Correlations ◽  
Or Efficiency ◽  
Economic Values ◽  
Lean Growth ◽  
Component Traits ◽  
Economic Selection

ABSTRACTIn meat animals there is some interest in lean growth rate or lean food conversion efficiency as selection criteria. These traits may be estimated as the product of growth rate (or efficiency), killing-out proportion and carcass lean proportion. When used as selection criteria these product traits do not require estimates of genetic parameters or economic values for component traits. Hence, they may be more stable, and of longer-term use than classical economic selection indices. The purpose of this study is to compare expected responses to selection on product traits with expected responses from selection, either on individual component traits, or on an economic selection index. Formulae were derived for predicting the phenotypic and genetic correlations between a product and one component, and for predicting the heritability of the product trait; these depend on the coefficients of variation and heritabilities of components, and on the genetic correlations among them. When the coefficient of variation of one component is much higher than that of the other, (× 3), this component will tend to dominate the product trait. In cattle and sheep, and to a lesser extent in pigs, killing-out proportion and leanness are usually less variable than growth rate or efficiency. Thus, in many cases, there is little loss in response in lean growth (or lean efficiency) from selection solely on growth rate (or efficiency) regardless of leanness. Although product traits do not require derivation of economic values, their component traits do have implied economic values. Often more appropriate weightings will be given to components by using an economic selection index, even when economic values and genetic parameters are not estimated precisely.

Reaction of Selected Peanut Varieties and Breeding Lines to Southern Stem Rot1

1997 ◽  
Vol 24 (1) ◽  
pp. 6-9 ◽  
Author(s):  
B. A. Besler ◽  
W. James Grichar ◽  
O. D. Smith
Keyword(s):  
Disease Resistance ◽  
West Africa ◽  
Burkina Faso ◽  
Disease Incidence ◽  
Sclerotium Rolfsii ◽  
Field Conditions ◽  
Breeding Line ◽  
Breeding Lines ◽  
Yield Increase

Abstract Eight Texas and one Georgia breeding lines, four accessions from Burkina Faso (West Africa), and six runner and two spanish-type cultivars were compared for yield, grade, and susceptibility to Sclerotium rolfsii Sacc. for 3 yr under irrigated field conditions. The spanish-type cultivar Tamspan 90 and runner-type breeding line TX896100 (recently released as Tamrun 96) consistently had the lowest disease incidence for all 3 yr. Averaged over years, TX896100 was the highest yielding entry. Four breeding lines resulted in a 2 to 16% yield increase over Okrun, the highest yielding cultivar. The African accessions, in general, produced low yields and low grades with no advantages in disease resistance.

Maximizing genetic gain for the sire line of a crossbreeding scheme utilizing both purebred and crossbred information

1998 ◽  
Vol 66 (2) ◽  
pp. 529-542 ◽  
Author(s):  
P. Bijma ◽  
J. A. M. van Arendonk
Keyword(s):  
Linkage Disequilibrium ◽  
Selection Index ◽  
Optimum Number ◽  
Linear Unbiased Prediction ◽  
Index Procedure ◽  
Breeding Goal ◽  
Breeding Schemes ◽  
Best Linear Unbiased ◽  
Estimated Breeding Values ◽  
Selection Intensities

AbstractA selection index procedure which utilizes both, purebred and crossbred information was developed for the sire line of a three-path crossbreeding scheme in pigs, to predict response to best linear unbiased prediction (BLUP) selection with an animal model. Purebred and crossbred performance were treated as correlated traits. The breeding goal was crossbred performance but methods can be applied to other goals. A hierarchical mating structure was used. Sires were mated to purebred dams to generate replacements and to F^ from the dam line to generate fattening pigs. Generations were discrete, inbreeding was ignored. The selection index included purebred and crossbred phenotypic information of the current generation and estimated breeding values for purebred and crossbred performance of parents and mates of parents from the previous generation. Reduction of genetic variance due to linkage disequilibrium and reduction of selection intensity due to finite population size and due to correlated index values was accounted for. Selection was undertaken until asymptotic responses were reached. The index was used to optimize the number of selected parents per generation and the number of offspring tested per litter, and to make inferences on the value of crossbred information when the breeding goal was crossbred performance. It was optimal to test a maximum number of offspring per litter, mainly due to increased female selection intensities. Maximum response reductions due to linkage disequilibrium and correlated index values were 32% and 29% respectively. Correcting for correlated index values changed ranking of breeding schemes. Benefit of crossbred information was largest when the genetic correlation between purebred and crossbred performance was low. Due to high correlations between index values in that case, the optimum number of selected sires increased considerably when crossbred information was included.

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