Phenotypic mass selection - genetic gain, choice of traits and indirect response.

The objective of the paper was to investigate annual genetic gain from selection (G), and the influence of selection on the inbreeding effective population size (Ne), for different possible breeding schemes within a reindeer herding district. The breeding schemes were analysed for different proportions of the population within a herding district included in the selection programme. Two different breeding schemes were analysed: an open nucleus scheme where males mix and mate between owner flocks, and a closed nucleus scheme where the males in non-selected owner flocks are culled to maximise G in the whole population. The theory of expected long-term genetic contributions was used and maternal effects were included in the analyses. Realistic parameter values were used for the population, modelled with 5000 reindeer in the population and a sex ratio of 14 adult females per male. The standard deviation of calf weights was 4.1 kg. Four different situations were explored and the results showed: 1. When the population was randomly culled, Ne equalled 2400. 2. When the whole population was selected on calf weights, Ne equalled 1700 and the total annual genetic gain (direct + maternal) in calf weight was 0.42 kg. 3. For the open nucleus scheme, G increased monotonically from 0 to 0.42 kg as the proportion of the population included in the selection programme increased from 0 to 1.0, and Ne decreased correspondingly from 2400 to 1700. 4. In the closed nucleus scheme the lowest value of Ne was 1300. For a given proportion of the population included in the selection programme, the difference in G between a closed nucleus scheme and an open one was up to 0.13 kg. We conclude that for mass selection based on calf weights in herding districts with 2000 animals or more, there are no risks of inbreeding effects caused by selection.

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Substantial Realized Gains from Mass Selection of Fusiform Rust-Free Trees in Highly Infected Stands of Slash Pine

Southern Journal of Applied Forestry ◽

10.1093/sjaf/14.3.143 ◽

1990 ◽

Vol 14 (3) ◽

pp. 143-146 ◽

Cited By ~ 6

Author(s):

G. R. Hodge ◽

R. A. Schmidt ◽

T. L. White

Keyword(s):

Genetic Gain ◽

Pinus Elliottii ◽

Slash Pine ◽

Mass Selection ◽

Realized Heritability ◽

Fusiform Rust ◽

Rust Infection ◽

Progeny Tests ◽

Selection Of

Abstract Three independent slash pine (Pinus elliottii var. elliottii) populations were formed through mass selection of fusiform rust-free individuals in stands with over 90% infection. Realized gain estimates were developed by comparing offspring from 592 selections to unimproved material in 46 progeny tests, and indicate substantial genetic gain in resistance. Across all tests of the three populations, unimproved material incurred nearly the entire possible range of infection from 0 to 100%. When both parents were rust-free selections, progeny rust infection was only two-thirds of the rust infection incurred by unimproved material at all levels of rust hazard. Realized heritability is high (hr2 ≅ 0.35), and increased resistance is evident in nearly all environments. This indicates that substantial genetic gain can be made by mass selection of healthy trees in highly infected stands. South. J. Appl. For. 14(3):143-146.

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The use of genetic algorithms for optimizing age structure in breeding populations when inbreeding depresses genetic gain through effects on reproduction

Animal Science ◽

10.1017/s1357729800050517 ◽

1999 ◽

Vol 68 (3) ◽

pp. 457-499 ◽

Cited By ~ 2

Author(s):

S. A. Meszaros ◽

R. G. Banks ◽

J. H. J. van der Werf ◽

M. Goddard

Keyword(s):

Genetic Gain ◽

Age Groups ◽

Mass Selection ◽

Female Population ◽

Female Age ◽

Male And Female ◽

Breeding Female ◽

Breeding Populations ◽

Potential Loss ◽

Complex Relationships

AbstractA genetic algorithm (GA) was used to find optimal male and female age distributions in a natural mating system that maximizes cumulative response to mass selection over a 20-year time horizon for the case where inbreeding affects reproduction at 0·0 (F-0) and 0·1 (F-10) per 0·1 inbreeding coefficient. Twenty breeding female population sizes were considered ranging from 25 to 500 breeding females distributed across five age groups. Loss of response due to inbreeding effects on reproduction ranged from 19.4% and 15.5% in small breeding female populations to 2.5% and 5.2% in large breeding female populations when number of males was fixed (FX) or optimized (OP), respectively. OP resulted in an increase in response over FX ranging from 0·0 % to 69.3% for F-0 and 0·0 % to 77.6% for F-10. The potential loss of genetic gain that resulted from ignoring the inbreeding effects upon reproduction when they really existed ranged from 0·1 % to 44.6%. The potential loss of genetic gain that resulted from including inbreeding effects upon reproduction when they did not exist ranged from 0·1% to 3.9%. Optimal male and female age structures depended upon breeding female population size, the number of breeding males and inbreeding effects. Ignoring inbreeding effects upon reproduction may result in over estimation of response to selection. Use of a GA allowed accounting for complex relationships in the optimization.

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Genetic response to short-term index selection in females and mass selection in males of the Nigerian heavy local chicken ecotype

Nigerian Journal of Animal Production ◽

10.51791/njap.v44i2.1116 ◽

2020 ◽

Vol 44 (2) ◽

pp. 1-17

Author(s):

C. C. Ogbu ◽

C. C. Nwosu

Keyword(s):

Body Weight ◽

Genetic Gain ◽

Egg Production ◽

Index Selection ◽

Mass Selection ◽

Indigenous Chicken ◽

Multiple Trait ◽

Breeding Values ◽

Expected Gain ◽

Selection For

The study aimed to determine genetic gain in growth and egg production in the Nigerian indigenous chicken (NIC) subjected to multiple trait index selection for females and mass selection for males. The experimental birds (G generation) were generated from a reference 0 population of NIC and reared according to sire families from hatch. At point of lay, females were housed individually in laying cages for egg production. Hens were selected based on index scores calculated using an index of weighted breeding values constructed from own performance in body weight at first egg (BWFE), egg weight (EW) and egg production (EN), trait heritabilities and relative economic weights while cocks were selected based on own performance in body weight at 39 weeks of age (BW ). Selected parents were mated to 39 generate the G generation which in turn yielded the parents of the G generation. A control 1 2 population was used to measure environmental effects. Data were analyzed using the Restricted Maximum Likelihood (REML) computer programme. For hens, expected average direct genetic gain per generation was 12.58, 2.98g and 25.04g for EN, EW and BWFE, respectively while realized genetic gain was 2.19 and 1.59 for EN, 1.65 and 0.26g for EW, and -25.60 and 123.64g for BWFE for G and G generations, respectively. The corresponding 0 1 values for ratio of realized to expected genetic gains were 2.27 and 1.22, 3.15 and 0.24, and 0.95 and 2.21, respectively. Heritability (h2) ranged from 0.12 to 0.24 for EN, 0.34 to 0.43 for EW and 0.57 to 0.69 for BWFE, across the three generations. Similar improvements in BW 39 were observed in males with an average expected gain of 508.50g per generation. In conclusion, growth and egg production in the NIC can be improved using mass selection for cocks and index of weighted breeding values for hens.

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Comparing Genetic Variation within Red Winter Wheat Populations with and without Image-Based Optical Sorter Selection

Al-Qadisiyah Journal For Agriculture Sciences (QJAS) (P-ISSN 2077-5822 E-ISSN 2617-1479) ◽

10.33794/qjas.vol9.iss2.82 ◽

2019 ◽

Vol 9 (2) ◽

pp. 266-277

Author(s):

Hussein M. Khaeim ◽

Anthony Clark ◽

Tom Pearson ◽

Dr. David Van Sanford

Keyword(s):

Genetic Variation ◽

Fusarium Head Blight ◽

Heading Date ◽

Fusarium Head Blight Resistance ◽

Gibberella Zeae ◽

Mass Selection ◽

Head Blight ◽

Red Winter Wheat ◽

Two Populations ◽

Head Scab

Head scab is historically a devastating disease affecting not just all classes of wheat but also barley and other small grains around the world. Fusarium head blight (FHB), or head scab, is caused most often by Fusarium graminearum (Schwabe), (sexual stage – Gibberella zeae) although several Fusarium spp. can cause the disease. This study was conducted to determine the effect of mass selection for FHB resistance using an image-based optical sorter. lines were derived from the C0 and C2 of two populations to compare genetic variation within populations with and without sorter selection. Our overall hypothesis is that sorting grain results in improved Fusarium head blight resistance. Both of the used wheat derived line populations have genetic variation, and population 1 has more than population 17. They are significantly different from each other for fusarium damged kernel (FDK), deoxynivalenol (DON), and other FHB traits. Although both populations are suitable to be grown for bulks, population 1 seems better since it has more genetic variation as well as lower FDK and DON, and earlier heading date. Lines within each population were significantly different and some lines in each population had significantly lower FDK and DON after selection using an optical sorter. Some lines had significant reduction in both FDK and DON, and some others had either FDK or DON reduction. Lines of population 1 that had significant reduction, were more numerous than in population 17, and FDK and DON reduction were greater.

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Mass Selection in a Pig Population: Experimental Design and Responses to Direct Selection for Rapid Growth and Minimum Fat

Journal of Animal Science ◽

10.2527/jas1986.6261492x ◽

1986 ◽

Vol 62 (6) ◽

pp. 1492-1508 ◽

Cited By ~ 2

Author(s):

H. T. Fredeen ◽

Hitoshi Mikami

Keyword(s):

Experimental Design ◽

Rapid Growth ◽

Direct Selection ◽

Mass Selection ◽

Selection For

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“FLAGMAN” - NEW VARIETY OF BROMUS INERMIS

Vestnik of the Russian agricultural science ◽

10.30850/vrsn/2019/1/17-19 ◽

1970 ◽

pp. 17-19

Author(s):

N. I. Kashevarov ◽

R. I. Polyudina ◽

I. N. Kazarinova ◽

D. А. Potapov

Keyword(s):

Dry Matter ◽

Western Siberia ◽

Steppe Zone ◽

Forest Steppe ◽

Mass Selection ◽

New Variety ◽

Fodder Crops ◽

Experimental Base ◽

Siberian Research Institute ◽

Academy Of Sciences

A new cultivar of smooth bromegrass (Bromopsis inermis Leyss) Flagman was developed by methods of mass selection and polycross. Breeding and wild forms of various ecological and geographical origins are used as an initial material. The authors of the cultivar: Kazarinova I.N., Polyudina R.I., Straub A.A., Gomasco S.K. Studies were conducted on the Central experimental base of the Siberian research Institute of fodder crops of the Siberian Federal Scientific Centre of Agro-BioTechnologies of the Russian Academy of Sciences, located in the forest-steppe zone of Western Siberia (Novosibirsk region, Novosibirsk district, Krasnoobsk). The cultivar is mid-ripening: the period from the beginning of spring aftergrowing to mowing ripeness is 63-75 days and to full maturing of seeds is 95-111 days. The yield of dry matter is 8.3 t/ha, which exceeds the standard by 8%, seed yield - 0.62 t/ha, higher than the standard by 28%. The dry matter yield of the cultivar Flagman for the fourth year of use exceeded the standard by 23% and reached to 11.4 t/ha. The 1000 seeds weight is 3.0-3.4 g. The plant height is 90-140 cm. Tilling capacity is up to 40 stems per tuft. Foliage varies from 32 to 50% depending on the age of the grass and environment conditions. The resistance of the cultivar to brown rust and helminthosporiosis is higher than of the standard. The copyright certificate No. 71916 and patent No. 9653 were received.

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