Читать книгу Principles of Plant Genetics and Breeding - George Acquaah - Страница 114

Migration is important in small populations. It entails the entry of individuals into an existing population from outside. Because plants are sedentary, migration, when it occurs naturally, is via pollen transfer (gamete migration). The impact of this immigration will have on the recipient population will depend on the immigration rate and the difference in gene frequency between the immigrants and natives. Mathematically, ∆q = m(q _m − q _o), where ∆q = the changes in the frequency of genes in the new mixed population, m = the number of immigrants, q _m = the gene frequency of the immigrants, and q _o = gene frequency of the host. Plant breeders employ this process to change frequencies when they undertake introgression of genes into their breeding populations. The breeding implication is that for open‐pollinated (outbreeding) species, the frequency of the immigrant gene may be low, but its effect on the host gene and genotypes could be significant.