Partial Genome Transfer in Interspecific Tomato Hybrids

Abstract

The transfer of desirable traits from wild into cultivated species is a method to improve crops. For this purpose, interspecific sexual or somatic hybrids may be constructed. However, these species hybrids contain many unwanted traits of the wild species besides the desired ones, and are often sterile. Fertility is required to perform several backcrosses with the cultivated species to remove unwanted characters of the wild species. These problems may be circumvented by asymmetric somatic hybridisation. By this procedure protoplasts of one species, the recipient, are fused with inactivated (mostly by Röntgen- or gamma-irradiation) protoplasts of another species, the donor. The donor genome will be fragmented and the asymmetric hybrids will contain the complete genome of the recipient species and a small part of the donor genome. Several asymmetric hybrids were obtained already: the fraction of donor genome that was transferred varied from a few traits (1) to many chromosomes (2).