The basis of Solynta F1 hybrid breeding
The Solynta F1 hybrid breeding technology is based on the development of homozygous elite lines that are crossed to generate an F1 hybrid cultivar. The performance of the parent is gradually improved by crossing and selection and experimental F1 hybrids are field tested to evaluate their performance and commercialize the best products.
Although potato exists in different ploidy levels (di-, tri-, tetra-, penta-, and hexa-ploid), Solynta works usually on a diploid level because homozygous lines are much faster obtained at the diploid level than at the tetraploid level. And in addition, complex traits are much more efficient to breed for at the diploid level.
Addition of a new trait by backcrossing
New traits can be introduced from any germplasm as long as it is crossable with diploid elite lines. In two series of backcrossing followed by two generations of selfing and by using diagnostic molecular markers for the trait of interest and random markers for the recurrent parent genome an existing parent line can be enriched with such trait in two to three years.
Both parents can be used for backcrossing and this process can be repeated. In this way a series of derivatives of an existing F1 hybrid cultivar can be generated that all have basically the same genetic composition except for the introduced traits.
The F1 hybrid cultivar is generated by crossing two parent lines. This process can easily be upgraded to a high throughput seed production system, like they are already in place at many other crops. As one plant can produce over 10.000s of seeds and the parent lines are propagated by selfings, any quantity of F1 hybrid seeds can be produced in one season to fulfill the market needs.
Traditional potato breeding
Traditional potato breeding is based on crossings between two existing extremely heterozygous tetraploid cultivars to generate thousands random seedlings from which a new cultivar is selected. In general, one new cultivar is selected from 100,000 seedlings by five to ten years of testing. Selfings and backcrosses are not feasible by strong inbreeding depression. Wide crosses with wild related species very rarely occur as it takes three rounds of breeding and selection and hence more than 20 years to create a new commercial cultivar, if you’re lucky.
Traditional clonal propagation
Traditionally, seed potatoes are vegetatively produced by specialized farmers as the start material for next season of commercial potato production. The multiplication factor is about ten. The quality of seed potatoes is continuously at risk for contamination with pathogens and insects during growth, harvest and storage. It takes five to seven years of clonal propagation to get sufficient seed potatoes to fulfill the market need of a successful cultivar.