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Variance Effective Population Size under Mixed Self and Random Mating with Applications to Genetic Conservation of Species
Author(s) -
Vencovsky Roland,
Crossa José
Publication year - 1999
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/cropsci1999.3951282x
Subject(s) - selfing , biology , effective population size , population , statistics , inbreeding , genetic drift , accession , mating , population size , sample size determination , germplasm , mating system , sampling (signal processing) , mathematics , zoology , genetic variation , ecology , botany , genetics , demography , physics , gene , european union , sociology , detector , economic policy , optics , business
When collecting and regenerating genetic resources, genetic drift affects the representation of a population and occurs at two stages: when sampling the parents and when gametes are sampled from these parents. The variance effective population size [ N e ( v ) ] quantifies genetic drift. In this study, a model for calculating N e ( v ) , that considers the two‐stage sampling of mixed self and random mating species, is developed. For germplasm collection, as the rate of natural or artificial self‐fertilization ( s ) increases, N e ( v ) is reduced and becomes increasingly dependent on the number of seed parents ( P ) and is less influenced by the number of seeds sampled per parent ( n/P ). Female gametic control (GC) leads to higher N e ( v ) than with random sampling of seeds (RS), but its effect is tangible only when n/P is small. For accession regeneration, maintaining accession integrity (the proportion of functional parents, u ) at an adequately high level and adopting GC are required for assuring N e ( v ) equal to or greater than the actual size of the accession ( N e ( v ) ≥ n ). The importance of these two factors is enhanced as s increases. For arbitrary rates of selfing (0 ≤ s ≤ 1), under inbreeding equilibrium (IE) and with constant population size ( n = N ), N e ( v ) can be adequately maintained through GC with a loss of ≤20% within accessions. For large sample size ( n → ∞), an accession loss of ≤33% can be recovered. For maintaining adequate N e ( v ) , artificial selfing followed by GC is more efficient than accession regeneration by natural reproduction. For achieving appropriate N e ( v ) s, increasing the rate of self‐fertilization in polymorphic materials makes collection more difficult but regeneration easier for minimal loss (≤20%) within accessions.