Potato haploid technologies

Abstract

The term ‘dihaploid’ is used to describe a plant which contains the haploid number of somatic chromosomes but which contains two genomes per somatic cell. The common potato Solanum tuberosum L. has 48 chromosomes per somatic cell (2n=4x=48), so that the number of chromosomes in the egg cell and in haploid somatic cells is 24. Haploids of S. tuberosum have been the subject of widespread study because they promised a means of investigating the genetic architecture of the world’s most commercially important broad-leaved crop. As the common potato is tetraploid, genetic investigations using it involve much more complex numbers than those arising from the use of diploid plants. Dihaploids offered a means of breeding the common potato at the diploid level. It is important to note, however, that the tetraploid state is generally regarded as the physiologically most efficient ploidy level for potato. Tetraploid S. tuberosum potatoes have commercial yields that far outweigh those of their dihaploid counterparts. It is therefore necessary to have technologies that can both generate haploid plants and regain the tetraploid chromosome level.