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ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #88867
Title: POPULATION GENETICS OF INCREASED HYBRID PERFORMANCE BETWEEN TWO MAIZE POPULATIONS UNDER RECIPROCAL RECURRENT SELECTION

Author
item Labate, Joanne
item Lamkey, Kendall
item LEE, MICHAEL - IOWA STATE UNIVERSITY
item WOODMAN, WENDY - IOWA STATE UNIVERSITY

Submitted to: Genetics and Exploitation of Heterosis in Crops
Publication Type: Proceedings
Publication Acceptance Date: 2/13/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: We examined allele frequencies from three populations within BSSS(R) and BSCB1(R) representing three different stages in their selective history: Progenitors (P) (collections of inbred lines), Cycle 0 (C0) (representing populations before selection and Cycle 12 (C12) (representing populations after 12 cycles of reciprocal recurrent selection). Leaf samples were collected from 100 plants from each C0 and C12 population, as well as single plants from all available inbred progenitor lines (16 and 12 lines representing BSSS and BSCB1, respectively). DNA was isolated and all 428 individuals were genotyped at 82 restriction fragment length polymorphism (RFLP) loci randomly distributed throughout the nuclear genome. A statistical test (Waples, 1989) was applied to each locus to detect if any of the observed changes in allele frequency between C0 and C12 within populations were greater than expected by drift alone. We found 11 and 17 loci rejected the null hypothesis of drift in BSSS(R) and BSCB1(R), respectively. These loci were not limited to particular chromosomes or regions but seemed to be spread throughout the genome. They fit a pattern of fixation of complementary alleles between the two population because none of the loci were shared except one, and at this locus a different allele was approaching fixation in BSSS(R) and BSCB1(R). We estimated mean expected heterozygosity of interpopulation crosses and found no significant difference between BSSS(R)C0 x BSCB1(R)C0 and BSSS(R)C12 x BSCB1(R)C12 for all 82 loci. However, the 27 nonneutral loci increased in mean expected heterozygosity for the interpopulation cross between C0 and C12 whereas the 55 neutral loci did not.