This information is critical to our kiwifruit breeding programmes. Another technique available to breeders in their quest to develop new cultivars is mutation breeding or mutagenesis. A mutation is a change in the structure of a gene. In most cases, this is deleterious as it means that the gene doesn't produce what it should. However, mutations can result in valuable new traits.
Spontaneous mutations happen in nature at a relatively frequent rate.
In fruit trees, large numbers of spontaneous mutations have been recorded and used either directly as new cultivars or in breeding programmes. Recent decades have witnessed intensive work on the induction of mutations by using irradiation, chemicals and other mutagenic agents. The frequency of induced mutations almost doubles those occurring naturally and they have been looked on as a powerful tool for the development of new cultivars. However, available mutagens cause not only changes in genes but also chromosomal aberrations, many of which are deleterious in their effect on the trait and on the entire organism. Consequently, there has been a limited number of induced mutations directly usable as new cultivars.