Читать книгу Principles of Plant Genetics and Breeding - George Acquaah - Страница 185

Early generation testing is a selection procedure in which the breeder initiates testing of genetically heterogeneous lines or families in an earlier than normal generation. In Chapter 15, recurrent selection with testers was used to evaluate materials in early generations. A major consideration of the breeder in selecting a particular breeding method is to maximize genetic gain per year. Testing early, if effective, helps to identify and select potential cultivars from superior families in the early phase of the breeding program. The early generation selection method has been favorably compared with other methods such as pedigree selection, single‐seed‐descent, and bulk breeding. The question of how early the test is implemented often arises. Should it be in the F₁‐, F₂‐, or F₃‐derived families? Factors to consider in deciding on the generation in which selection is done include the trait being improved, and the availability of off‐season nurseries to use in producing additional generations per year (in lieu of selecting early).