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Articles 1 - 4 of 4
Full-Text Articles in Social and Behavioral Sciences
Expression Of Heterosis In Leaming And Midland Corn Belt Dent Populations, M. J. Carena, A. R. Hallauer
Expression Of Heterosis In Leaming And Midland Corn Belt Dent Populations, M. J. Carena, A. R. Hallauer
Journal of the Iowa Academy of Science: JIAS
Successful maize (Zea mays 1.) breeding programs are based on specific heterotic patterns. The Iowa Stiff Stalk Synthetic x Lancaster Sure Crop heterotic pattern is widely exploited in U.S. maize breeding programs. Alternative U.S. heterotic patterns have been suggested, but they have received limited attention and improvement. The objectives of this study were to evaluate cultivar crosses between Leaming and Midland Yellow Dent cultivars before and after inbred progeny selection and to assess their potential as an alternative U.S. heterotic pattern. Grain yield had a midparent heterosis value of 4.9% before selection and 17.8% in the third cycle of selection. …
Inheritance And Number Of Genes Affecting Quantitative Traits Within F2 Maize Populations, D. H. Schmidt, A. R. Hallauer
Inheritance And Number Of Genes Affecting Quantitative Traits Within F2 Maize Populations, D. H. Schmidt, A. R. Hallauer
Journal of the Iowa Academy of Science: JIAS
Populations derived from crosses of elite genotypes are commonly used in plant breeding programs. Knowledge of the genetic variation among individuals and their progenies within F2 populations is essential for effective selection of important traits. The genetic variation and number of effective factors affecting the expression of quantitative traits within 30 F2 maize (Zea mays L.) populations were determined by different methods suggested for study of F2 populations. Estimates of heritability and number of effective factors varied among F2 populations for each trait, primarily because of the differences in trait expression between parents of crosses and the environmental effects upon …
Genetic Variation Among And Within S1 Progenies Of Maize, R. J. Getschman, A. R. Hallauer
Genetic Variation Among And Within S1 Progenies Of Maize, R. J. Getschman, A. R. Hallauer
Journal of the Iowa Academy of Science: JIAS
Inbred line development consumes a great portion of the breeder's time and resources in maize (Zea mays L.) breeding programs. Source populations for line development often are developed by selfing F2 populations developed from elite line crosses. Visual selection is practiced among and within selfed progenies during the selection process for one or two generations before evaluated in testcrosses for combining ability. Effective discrimination among and within inbred and testcross progenies depends on the amount of genetic variation present. The objective of this study was to determine the effectiveness of selection among and within S1 progenies developed from crosses …
Estimates Of Genetic Variability In F2 Maize Populations, Geng-Chen Han, A. R. Hallauer
Estimates Of Genetic Variability In F2 Maize Populations, Geng-Chen Han, A. R. Hallauer
Journal of the Iowa Academy of Science: JIAS
Maize (Zea mays L.) breeders emphasize selection within F2 populations derived from crosses of inbred lines: Studies of the inheritance of quantitative traits in maize have been conducted primarily for generically broad-based populations. Objectives of our study were to estimate the generic variability in F2 populations developed from crosses of related and unrelated lines and to determine the effects of five generations of random intermating of plants within F2 populations on the estimates of genetic variability. Estimates of additive genetic variability were greater in the unrelated line crosses, but the estimates were not significantly different before and …