Development and Selection of Productive S1 Inbred Lines of Corn (<i>Zea mays</i> L.)<sup>1</sup>

Genter, C. F.; Alexander, M. W.

doi:10.2135/cropsci1966.0011183x000600050011x

Cited by 27 publications

(23 citation statements)

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“…Wright (1977) found that Si testing compared favourably with half-sib and testcrossing for a range of models which included ambi-directional dominance and epistasis, and the present study has confirmed that this method has a robustness in the face of differing genetic conditions which lead to its general superiority over other progeny testing methods for typical trial designs. The considerable weight of experimental evidence in maize also indicates a general superiority of this method (Genter and Alexander, 1966;Genter, 1973;Carangal et al 1971;Lonnquist, 1968).…”

Section: Discussiormentioning

confidence: 99%

The expected efficiencies of half-sib, testcross and S1 progeny testing methods in single population improvement

Wright

1980

Heredity

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SUMMARYExpressions are given for the expected rate of response to selection using half-sib, Si or testcross progeny tests for biallelic loci with arbitrary dominance and epistatic properties. It is shown that the value of a tester is not necessarily expected to be a simple function of either its phenotype or of the number of recessive alleles it carries, and that neither downward selection nor inbreeding are expected to be consistently successful in isolating superior testers. Calculation of expected annual responses to selection under a variety of genetic models shows that, while mass selection is the most efficient method at high heritabilities, Si testing is expected to be the best method for low heritabilities when replicated block trials are used. Conventional half-sib testing may have an advantage with complete randomisation of large families, especially for genetic models involving overdominance, deleterious recessives or epistasis in biennial or perennial crops. The use of the lowest homozygote tester was inferior to Si testing for all models including simple directional dominance. Assumptions of low environmental homoeostasis of Si material did not alter the general conclusions.Monte Carlo simulations of breeding procedures confirmed the overall superiority of Si testing in terms of response per cycle, and a system of mass selection followed by Si testing gave a higher average response per year than did either mass selection or Si testing alone.

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Section: Discussiormentioning

confidence: 99%

The expected efficiencies of half-sib, testcross and S1 progeny testing methods in single population improvement

Wright

1980

Heredity

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“…Diante da existência de variabilidade entre progênies oriundas de autofecundação, torna-se possível selecionar genótipos com menor depressão endogâmica (Genter & Alexander, 1966) ou com características desejáveis, conforme procedimento adotado na seleção do cultivar Mott (Sollenberger & Jones Jr., 1989).…”

Section: Resultsunclassified

Ensaios preliminares sobre autofecundação e cruzamentos no melhoramento do capim-elefante

Silva

Santos

Lira³

et al. 2008

R. Bras. Zootec.

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RESUMO -Objetivou-se nesta pesquisa verificar a possibilidade do uso da autofecundação no melhoramento doPennisetum purpureum e comparar progênies de Pennisetum purpureum obtidas por três formas de fecundação (tratamentos): autofecundação, cruzamentos intraespecíficos e cruzamentos interespecíficos com Pennisetum glaucum.Foram avaliadas 10, 2 e 2 famílias com um total de, respectivamente, 160 progênies provenientes de cruzamento intraespecífico, 38 progênies de cruzamento interespecífico e 40 progênies de autofecundação. Foram realizadas duas avaliações para determinar a produção de matéria seca -MS (kg/touceira), o teor de MS (%), a altura de planta (m), o perfilhamento basilar (nº/touceira) e índice de sobrevivência (%), em parcelas sem repetição. Os tratamentos cruzamento intraespecífico, cruzamento interespecífico e autofecundação apresentaram as respectivas médias de 0,47; 0,78 e 0,46 e de 0,14; 0,23 e 0,22 kg de MS/touceira, respectivamente, na primeira e segunda avaliações. Experimentos com parcelas repetidas devem ser conduzidos visando isolar os efeitos de meio dos efeitos genéticos. O cruzamento interespecífico mostrou-se promissor na geração de genótipos com porcentagem de MS adequada ao processo de ensilagem. Todos os tratamentos apresentaram potencial para liberar variabilidade nos caracteres avaliados, entretanto, o baixo índice de sobrevivência das progênies provenientes da autofecundação dificulta a obtenção de linhas puras.Palavras-chave: caracteres produtivos, clones, depressão endogâmica, híbrido, teor de matéria seca, sobrevivência Preliminary tests on self-pollination and crossbreed in elephantgrass breedingABSTRACT -The objectives of this work were to evaluate the self-pollination as a tool in the elephantgrass (Pennisetum purpureum) breeding and to compare progenies of Pennisetum purpureum origined from different breeding strategies: self-pollination, intraspecific crossbreeds, and interspecific crossbreeds with Pennisetum glaucum. The experimental treatments were represented by the three fecundation forms: intraspecific crossbreed, interspecific crossbreed and self-pollination. A total of ten families originated from intraspecific crossbreed resulting in 160 progenies; two families originated from interspecific crossbreed resulting in 38 progenies, and two families originated from selfpollination resulting in 40 progenies, was evaluated. The evaluated traits were dry matter production (kg/tussock), dry matter concentration (%), plant height (m), number of basal tillers (n./tussock) and survival index (%), in two evaluations and non-replicated plots. The intraspecific crossbreed, interspecific crossbreed and self-pollination presented average dry matter production of 0.47, 0.78, and 0.46 kg of DM/tussock, at first evaluation and 0.14, 0.23, and 0.22 kg of DM/ tussock, at second evaluation, respectively. This indicates the necessity of plot replication to separate the environmental effect from the genetic effect. The interspecific crossbreed showed potential to generate progenies with satis...

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“…Center and Alexander (1962) compared the performance of SI progenies and testcrosses and concluded that if heterosis was a result of additive effects from dominant genes, progeny performance of early generation inbred lines should evaluate their general combining ability better than testcrosses. Center and Alexander (1966), working with Corn Belt Southern Synthetic, reported an increase of 31.4% and 17.9% in the mean yield of SI lines after two cycles of selection for SI families and testcrosses, respectively. They also found that the more productive Si lines tended to produce the more productive crosses, but that relationship decreased with each cycle of selection.…”

Section: Inbred Family Selectionmentioning

confidence: 99%

Efficiency of S2 recurrent selection for improvement of exotic and semi-exotic populations in maize (Zea mays L.)

Iglesias

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Iglesias, Carlos Ariel, "Efficiency of S2 recurrent selection for improvement of exotic and semi-exotic populations in maize (Zea mays L.) " (1989). Retrospective Theses and Dissertations. 9199. https://lib.dr.iastate.edu/rtd/9199 INFORMATION TO USERSThe most advanced technology has been used to photo graph and reproduce this manuscript from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer.The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction.In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.Oversize materials (e.g., maps, drawings, charts) are re produced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. These are also available as one exposure on a standard 35mm slide or as a 17" x 23" black and white photographic print for an additional charge.Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. University Microfilms International 1989Signature was redacted for privacy.Signature was redacted for privacy.Signature was redacted for privacy.ii (Russell, 1986). Even if the most sophisticated and efficient breeding method is developed, the efforts of the breeder will be futile if the genes are not present in the original population. Choosing the initial germplasm and the breeding procedure are two equally important decisions that maize breeders have to make .The restricted genetic base of maize production and breeding in the U.S. Corn Belt region has two main consequences: an increased vulnerability of biological and environmental stresses; and a reduction in the genetic variability available to the breeder for selection. The emergence of many effective seed companies with extensive testing programs led to the identification of elite, widely adapted hybrids, from which both farmers and seed companies benefit (Bradley et al., 1988). Genetic vulnerability can be reduced if a measurement of genetic diversity for commercial hybrids could influence the farmer's choice among top performing hybrids, prompting seed companies to broaden the genetic base of their hybrids . 2When gerraplasm from a wild species or an exotic race contributes to a breeding program, it...

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Development and Selection of Productive S1 Inbred Lines of Corn (Zea mays L.)¹

Cited by 27 publications

References 0 publications

The expected efficiencies of half-sib, testcross and S1 progeny testing methods in single population improvement

The expected efficiencies of half-sib, testcross and S1 progeny testing methods in single population improvement

Ensaios preliminares sobre autofecundação e cruzamentos no melhoramento do capim-elefante

Efficiency of S2 recurrent selection for improvement of exotic and semi-exotic populations in maize (Zea mays L.)

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Development and Selection of Productive S1 Inbred Lines of Corn (Zea mays L.)1

Cited by 27 publications

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The expected efficiencies of half-sib, testcross and S1 progeny testing methods in single population improvement

The expected efficiencies of half-sib, testcross and S1 progeny testing methods in single population improvement

Ensaios preliminares sobre autofecundação e cruzamentos no melhoramento do capim-elefante

Efficiency of S2 recurrent selection for improvement of exotic and semi-exotic populations in maize (Zea mays L.)

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Development and Selection of Productive S1 Inbred Lines of Corn (Zea mays L.)¹