Quantitative Genetics of Inbreeding in a Synthetic Maize Population
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The Department of Agronomy seeks to teach the study of the farm-field, its crops, and its science and management. It originally consisted of three sub-departments to do this: Soils, Farm-Crops, and Agricultural Engineering (which became its own department in 1907). Today, the department teaches crop sciences and breeding, soil sciences, meteorology, agroecology, and biotechnology.
History
The Department of Agronomy was formed in 1902. From 1917 to 1935 it was known as the Department of Farm Crops and Soils.
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1902–present
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- Department of Farm Crops and Soils (1917–1935)
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- College of Agriculture and Life Sciences (parent college)
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Abstract
The average effects of inbreeding depression have been measured extensively in maize (Zea mays L.), but the influence of inbreeding on genetic variance has not been well studied. Two hundred random S1, S2, S3, and S4 lines were developed from the BS13(S)C0 population by single-seed descent and a set of 200 related half-sib families were developed from the S1 lines. The lines and half-sib families were evaluated in replicated yield trials for six agronomic characters. Under a purely additive model, the expected variance among inbred individuals is exactly twice the variance of noninbred individuals. The observed variance of inbred individuals in our study was 1.18 times the variance of noninbred individuals or less for five of six traits studied. By contrast, variance of dominance deviations of inbred individuals ranged from 1.6 to 3.3 times the variance of dominance deviations of noninbred individuals for five of six traits studied. A negative covariance between dominance deviations and breeding values in inbred individuals was found for all six traits. An estimator of the degree of dominance for arbitrary allele frequencies was developed. The estimated average degree of dominance in BS13(S)C0 ranged from 1.28 to 2.76, corresponding to overdominance or pseudo-overdominance. Our results suggested that some regions of linked genes have large effects on inbreeding depression in this population.
Comments
This article is published as Edwards, Jode W., and Kendall R. Lamkey. "Quantitative genetics of inbreeding in a synthetic maize population." Crop science 42, no. 4 (2002): 1094-1104. doi: 10.2135/cropsci2002.1094. Posted with permission.