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Effect of Reciprocal Recurrent Selection for Yield on Isozyme Polymorphisms in Maize ( Zea mays L.) 1
Author(s) -
Brown A. H. D.,
Allard R. W.
Publication year - 1971
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1971.0011183x001100060038x
Subject(s) - biology , zea mays , genetics , linkage disequilibrium , allele , genetic drift , selection (genetic algorithm) , isozyme , population , recombination , genetic variability , genetic variation , genotype , gene , haplotype , agronomy , enzyme , biochemistry , demography , artificial intelligence , sociology , computer science
Nine isozyme polymorphisms were used to monitor the genetic effects of two cycles of reciprocal recurrent selection of a population of maize ( Zea mays L.). The results indicate that RRS had little effect on gene or genotypic frequencies; the few changes that occurred could be ascribed to random genetic drift associated with restriction of population size (to about N = 30) at the time of selection of lines for advance to the next cycle of RRS. Studies of the joint distribution of alleles at pairs of loci revealed two further effects of random genetic drift at the time of selection: (i) generation of sporadic linkage disequilibrium or gametic unbalance; and (ii) loss of rare recombinants between closely‐linked loci, thereby restricting the release of variability through recombination. Thus, random events played a major role in the behavior of the linkage blocks marked by these isozyme loci. Implications concerning RRS as a scheme of maize improvement are discussed.