Twenty Years of Reciprocal Recurrent Selection with Two Synthetic Varieties of Maize (<i>Zea mays</i> L.)<sup>1</sup>

Penny, L. H.; Eberhart, S. A.

doi:10.2135/cropsci1971.0011183x001100060041x

Cited by 64 publications

(70 citation statements)

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“…Estimates of genotypic and phenotypic components were calculated from ANOVA and used to calculate heritability on an entry-mean basis (Penny and Elbert, 1971;Carson et al, 2004) as follows:…”

Section: Discussionmentioning

confidence: 99%

Change in heritability estimates due to half-sib family selection in the maize variety Pahari

Noor

Shahwar²,

Rahman³

et al. 2013

Genet. Mol. Res.

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and grain yield were recorded. The results revealed significant differences among families for all traits in both cycles. High heritability (0.88) was observed for days to mid-silking in cycle 0 (C 0 ), while moderate heritability (0.42) was recorded for 100-grain weight in C 1 . The selection differential was quite reasonable and varied according to the traits of interest. The observed response for grain yield in C 0 (815.74 kg/ha) was greater than the expected response (681.76 kg/ha).

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Section: Discussionmentioning

confidence: 99%

Change in heritability estimates due to half-sib family selection in the maize variety Pahari

Noor

Shahwar²,

Rahman³

et al. 2013

Genet. Mol. Res.

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“…The BSSS and BSCB1 populations have been undergoing RRS since 1949 (Penny and Eberhart 1971). Our study examines samples from three populations within BSSS(R) and BSCB1(R) representing three different stages in their selective history.…”

Section: Populationsmentioning

confidence: 99%

Temporal changes in allele frequencies in two reciprocally selected maize populations

Labate¹,

Lamkey²,

Lee

et al. 1999

Theor Appl Genet

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The effects of breeding on allele frequency changes at 82 restriction fragment length polymorphism (RFLP) loci were examined in two maize (Zea mays L.) populations undergoing reciprocal recurrent selection, Iowa Stiff Stalk Synthetic and Iowa Corn Borer Synthetic #1. After 12 cycles of selection, approximately 30% of the alleles were extinct and 10% near fixation in each population. A test of selective neutrality identified several loci in each population whose allele frequency changes cannot be explained by genetic drift; interpopulation mean expected heterozygosity increased for that subset of 28 loci but not for the remaining 54 loci. Mean expected heterozygosity within the two subpopulations decreased 39%, while the between-population component of genetic variation increased from 0.5% to 33.4% of the total. Effective population size is a key parameter for discerning allele frequency changes due to genetic drift versus those resulting from selection and genetic hitchhiking. Empirical estimates of effective population size for each population were within the range predicted by the breeding method. KeywordsEffective population size, Selection, Genetic drift, Diversity, Restriction fragment length polymorphism Abstract The effects of breeding on allele frequency changes at 82 restriction fragment length polymorphism (RFLP) loci were examined in two maize (Zea mays L.) populations undergoing reciprocal recurrent selection, Iowa Stiff Stalk Synthetic and Iowa Corn Borer Synthetic #1. After 12 cycles of selection, approximately 30% of the alleles were extinct and 10% near fixation in each population. A test of selective neutrality identified several loci in each population whose allele frequency changes cannot be explained by genetic drift; interpopulation mean expected heterozygosity increased for that subset of 28 loci but not for the remaining 54 loci. Mean expected heterozygosity within the two subpopulations decreased 39%, while the between-population component of genetic variation increased from 0.5% to 33.4% of the total. Effective population size is a key parameter for discerning allele frequency changes due to genetic drift versus those resulting from selection and genetic hitchhiking. Empirical estimates of effective population size for each population were within the range predicted by the breeding method.

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“…The tendency for genetic variance to decrease with time has been noted in several recurrent selection programs (Hallauer, 1970;Burton et al, 1971;Penny and Eberhart, 1971), though not in others (Darrah et al, 1972); this may be largely the result of restricted population sizes. In the long term, selection uses up genetic variation, although the persistence of variation has been noted after 4 0 and 76 generations, respectively, in the in vestigations of Frankham et al (1968c) and Dudley (1976).…”

Section: Application Of Index Selectionmentioning

confidence: 98%

“…Genetic drift is a probable factor in some of the selection studies with maize. In the experi ments described by Penny and Eberhart (1971) and Burton et al (1971), ten S^ lines were selected and recombined in each cycle, and observed responses were well below predicted levels. In contrast, Cortez-Mendoza and Hallauer (1979) reported unusually good agreement between expected and observed genetic changes in a mass selection experiment where 300 individuals were selected in each generation.…”

Section: Application Of Index Selectionmentioning

confidence: 99%

Selection Indices for the Improvement of Opaque‐2 Maize¹

Martin¹,

Loesch²,

Demopulos-Rodriguez³

et al. 1982

Crop Science

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The need to improve agronomic and protein and kernel quality characters in opaque‐2 maize (Zea mays L.) mandates consideration of multiple traits in selection. Data from genetic studies in an opaque‐2 maize synthetic were used to calculate selection indices for use in recurrent selection. Grain yield was considered the only trait having explicit economic value. Restricted indices were used to achieve satisfactory gains in kernel hardness, moisture content, and protein content and quality.The most important traits with respect to achieving the specified selection goals were yield, moisture content, kernel hardness, lysine content, kernel weight, and the degree of light transmission by kernels. Indices incorporating five traits were more efficient in that the addition of a sixth trait contributed very little to expected gains. The most effective combinations of traits for a recurrent selection scheme involving S1 testing were also the most effective for S2 testing and full‐sib testing.The degree to which gains predicted for an index were dependent on accurate estimates of the population parameters was considered. Indices having weights that implied reliance on indirect rather than direct selection response were not recommended.Substitution of single‐plant data for data from replicated progeny tests was considered in connection with each breeding scheme. The possibility of increasing the effective selection intensity, given that resources for replicated testing were fixed, by culling individual plants was investigated, but the use of individual plant data did not increase expected gain.A measure of subjective judgment on the part of the breeder is probably required for the successful application of selection indices to complex problems.

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Twenty Years of Reciprocal Recurrent Selection with Two Synthetic Varieties of Maize (Zea mays L.)¹

Cited by 64 publications

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Change in heritability estimates due to half-sib family selection in the maize variety Pahari

Change in heritability estimates due to half-sib family selection in the maize variety Pahari

Temporal changes in allele frequencies in two reciprocally selected maize populations

Selection Indices for the Improvement of Opaque‐2 Maize¹

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Twenty Years of Reciprocal Recurrent Selection with Two Synthetic Varieties of Maize (Zea mays L.)1

Cited by 64 publications

References 0 publications

Change in heritability estimates due to half-sib family selection in the maize variety Pahari

Change in heritability estimates due to half-sib family selection in the maize variety Pahari

Temporal changes in allele frequencies in two reciprocally selected maize populations

Selection Indices for the Improvement of Opaque‐2 Maize1

Contact Info

Product

Resources

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Twenty Years of Reciprocal Recurrent Selection with Two Synthetic Varieties of Maize (Zea mays L.)¹

Selection Indices for the Improvement of Opaque‐2 Maize¹