Dispersion-selection balance in localised plant populations

Nagylaki, T. (1976) Dispersion-selection balance in localised plant populations. Heredity, 37 (1). pp. 59-67.

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Two single-locus deterministic models are constructed for the maintenance of genetic variability in localized plant populations. In the first model it is assumed that self pollination is complete, heterozygotes are absent, only seeds disperse, and ploidy is arbitrary. In the second, it is assumed that the plants are diploid, cross pollination is total, and only pollen disperses. Explicit conditions for protected polymorphism are derived for each model in the diallelic "two-niche" case. These conditions are simplified, displayed graphically, and discussed extensively for directional selection for different alleles in the two niches. It is shown that if the amount of seed dispersal is divided by two, the criteria for a protected polymorphism in the self-pollinating system become identical with the criteria in the cross-pollinating system with no multiplicative dominance. The restrictions placed on the fitnesses for protected polymorphism become more stringent as the amount of dispersion increases. If the dispersion rate is not very close to zero and the selection coefficients are very small, the protection conditions are reduced to overdominance for the mean fitnesses in the habitat. Unless there is complex dominance, protection always exists with fixed fitnesses for sufficiently low dispersal above zero. For any amount of dispersion, there is always protection in the second model if, in each niche, the fitness of the deleterious homozygote is less than that of the heterozygote.

Item Type: Article
Additional Information: SNNigam Collection
Author Affiliation: Dep. Biophysics & Theoretical Biol., Chicago Univ., Ill., USA.
Subjects: Crop Improvement > Genetics/Genomics
Crop Improvement > Plant Breeding
Divisions: General
Depositing User: Mr Balakrishna Garadasu
Date Deposited: 02 Apr 2013 10:14
Last Modified: 02 Apr 2013 10:14
Official URL: http://dx.doi.org/10.1038/hdy.1976.65
URI: http://eprints.icrisat.ac.in/id/eprint/10041

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