HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hallauer, A. R. Articles by Sears, J. H. Search for Related Content PubMed Articles by Hallauer, A. R. Articles by Sears, J. H. Agricola Articles by Hallauer, A. R. Articles by Sears, J. H.

Changes in Quantitative Traits Associated with Inbreeding in a Synthetic Variety of Maize¹

Inbreeding studies were initiated in a synthetic variety of maize (Zea mays L.), ‘Iowa Stiff Stalk Synthetic’ (BSSS), in 1962 by selling 250 unseIected S₀ plants. One genotype of the zygotic array for each S₀ plant was maintained by single-seed descent for seven generations of selling. In the $7 generation, 248 lines from the original 250 So plants were available, and a bulk increase was made for each line. Five experiments were conducted in 1969 and 1970 to evaluate the agronomic changes associated with inbreeding (by selling) for 10 quantitative traits: plant and ear height, leaf width, kernel-row number, ear length and diameter, cob diameter, kernel depth, yield, and days to silk. Multiple-range tests of the combined means showed that most of the differences among generations S₀ through S₄ were significant. Except for ear diameter, kernel depth, and yield, the differences among generations S₅, S₆, and S₇ were not significant. Linear and quadratic models were fitted for the generation means for each trait on ercentage homozygosity. The regression analyses showed that the relation between the mean performance and levels of inbreeding in BSSS can be described by a genetic model based on the cumulative effects of loci with dominance for most traits; i.e. inbreeding depression resulted from an increase in the frequency of homozygous recessive deleterious loci. In BSSS, inbreeding to homozygosity would, on the average, reduce yield by 45 q/ha, decrease plant height by 48 cm, and increase days to silking by 4.6 days.

Key Words: Zea mays L. • Corn • Selfing • Rate of inbreeding depression

² Research Geneticist, ARS, USDA, and Professor of Agronomy, Iowa State University; and Agricultural Research Technician, respectively, Ames, Iowa 50010.

Received for publication September 20, 1972.

This article has been cited by other articles:

				B. M. Wardyn, J. W. Edwards, and K. R. Lamkey The Genetic Structure of a Maize Population: The Role of Dominance Crop Sci., March 1, 2007; 47(2): 467 - 474. [Abstract] [Full Text] [PDF]

				J. K. Kelly Epistasis in Monkeyflowers Genetics, December 1, 2005; 171(4): 1917 - 1931. [Abstract] [Full Text] [PDF]

				J. W. Edwards and K. R. Lamkey Dominance and Genetic Drift: Predicted Effects of Population Subdivision in a Maize Population Crop Sci., November 1, 2003; 43(6): 2006 - 2017. [Abstract] [Full Text] [PDF]

				J. W. Edwards and K. R. Lamkey Quantitative Genetics of Inbreeding in a Synthetic Maize Population Crop Sci., July 1, 2002; 42(4): 1094 - 1104. [Abstract] [Full Text] [PDF]