Potato Genetics for Crop Improvement

The most widely cultivated potato (Solanum tuberosum) is an autotetraploid (2n = 4x = 48). Potato genetics is studied in the context of crop improvement. The allele is the unit of selection, directly for those of large effect and indirectly for polygenic traits through the average effects of alleles which determine the breeding values of genotypes. Major genes can be mapped and candidate genes proposed as causal genes. Allelic variation can be explored to find the most desirable one for selection using a molecular marker, or even cloning. With sequence information available, causal genes can be targeted for gene editing involving gene knockout, or gene replacement, or gene insertion. Breeders’ objectives may be more easily achieved through the use of genetic transformation to produce a genetically modified (GM) crop with a number of examples of desirable phenotypes already achieved. Currently up to eight genes are being stacked in cultivars. Molecular markers can also be used in genomic selection of quantitative traits, but progress over sexual generations still depends on the additive genetic variance. The advent of diploid F1 hybrid breeding requires additional potato genetics, particularly on self-pollination, male and female fertility, seed set, and the elimination of deleterious alleles during inbreeding. As more potatoes have their genomes sequenced, and haplotypes of both diploids and tetraploids are reconstructed, it is time to evaluate the new information in the context of crop improvement.