Читать книгу Principles of Plant Genetics and Breeding - George Acquaah - Страница 19

The work of Gregor Mendel and further advances in science that followed his discoveries established that plant characteristics are controlled by hereditary factors or genes that consist of DNA (deoxyribose nucleic acid, the hereditary material). These genes are expressed in an environment to produce a trait. It follows then that in order to change a trait or its expression, one may change the nature or its genotype, and/or modify the nurture (environment in which it is expressed). Changing the environment essentially entails modifying the growing or production conditions. This may be achieved through an agronomic approach, for example the application of production inputs (e.g. fertilizers, irrigation). Whereas this approach is effective in enhancing certain traits, the fact remains that once these supplemental environmental factors are removed, the expression of the plant trait reverts to status quo. On the other hand, plant breeders seek to modify plants with respect to the expression of certain selected attributes by modifying the genotype (in a desired way by targeting specific genes). Such an approach produces an alteration that is permanent (i.e. transferable from one generation to the next).