Читать книгу Principles of Plant Genetics and Breeding - George Acquaah - Страница 93

The primary way of creating variability for breeding has been through artificial crossing (hybridization) or mutagenesis (induced mutations). Hybridization is best done between crossable parents. However, sometimes, breeders attempt to cross genetically distant parents, with genetic consequences. There are traditional schemes and techniques to address some of these consequences (e.g. wide cross, embryo rescue). The success of hybridization depends on the ability to select and use the best parents in the cross. Breeders have access to elite lines for use as parents. Further, biotech tools are now available to assist in identifying suitable parents for a cross, and also assist in introgressing genes from exotic sources into adapted lines. Transgenesis (genetic engineering involving gene transfer across natural biological boundaries), and more recently cisgenesis (genetic engineering involving gene transfer among related and crossable species) can be used to assist breeders in creating useful variability for breeding. In the case of mutagenesis, advances in technology have enabled breeders to be more efficient in screening mutants (e.g. by TILLING). Products from mutation breeding, not being transgenic, are more acceptable to consumers who are unfavorably disposed to GM crops.