Wageningen, The Netherlands
October 27, 2011

Solynta present the latest results on F1 hybrid potato breeding at the 8th Solanaceae and 2nd Cucurbitaceae Joint Meeting, 28 November – 2 December, Kobe, Japan.

Recently, the first draft DNA sequences of the potato genome have been established. The high frequencies of SNP’s, alleles, nonsense mutations and duplications reflect a flexible genome, whereby genetic variation is easily maintained due to the vegetative way of propagation. The tetraploid genome constitution also contributes to the maintenance of reduced fitness or even lethal alleles, as these can easily be compensated by favourable (dominant) alleles on the same locus.

The drawback of this genetically flexible species is a strong inbreeding depression, due to increased homozygosity frequencies of loci with deleterious or lethal alleles. As a consequence, breeders favour a tetraploid heterozygous potato crop and avoid inbreeding. This has resulted in a slow genetic improvement in potato and a stubborn believe among geneticists and breeders that inbreeding absolutely prevents the generation of homozygous lines. As a result, potato breeding is rather empiric with little genetic progress. A good example is good old Russet Burbank, still the main cultivar in US and introduced in 1876!

The tremendous genetic variation, the availability of genomic tools and our increasing knowledge of gene function should boost potato breeding. This is not achieved due to the traditional breeding system that does not allow inbreeding and backcrossing.
We aim at developing an alternative for traditional potato breeding by generating vigourous and essentially homozygous inbred lines. We favour diploids, as the progress in homozygosity frequency is much faster in diploids than in tetraploids. A drawback of diploid potato is the self-incompatibility. We took advantage of the Sli-gene (Phumichai et al., 2005), that inhibits the self-incompatibility in diploid potato, and introduced it into elite diploid germplasm as the start of a diploid breeding programme. In several generations of breeding, self-compatible inbred lines with improved agronomic performance were generated. In addition, inbred lines were intercrossed yielding the first F1 hybrid prototypes, with good agronomic performance.

We could show that most of the markers segregate according to a monogenic trait. Our best lines are more than 80% homozygous and show tuber yields close to the diploid controls. The perspectives for potato genetic research and breeding are unprecedented.

Website: http://www.solynta.com/

Published: October 28, 2011