Hybrid potatoes: Potato seed instead of seed potatoes

KWS is convinced that potatoes offer great potential. It is one of the most important staple foods worldwide, and the demand for potato products is increasing. This has also increased demand for the nightshade plant: Not only should the yield of the varieties increase, but also the quality of the compounds. The varieties currently on the market are usually already pretty much “long in the tooth” and breeding progress is limited. KWS has recognized an opportunity to exploit the potential of the potato using innovative approaches, in order to give farmers and their customers additional advantages, and to keep the potato competitive. To achieve this long-term goal, a three-pronged approach is being pursued, ranging from cultivation of competitive diploid potato varieties, to hybridization and development of seed.

A look at the genome of the potato clarifies the special challenges facing breeders: Today’s commercial potato varieties are tetraploid, meaning they have four sets of chromosomes. Each property is therefore present in four different forms (alleles). If tetraploid plants are crossed, the phenotypic appearance of the offspring splits much more strongly than with diploid plants. Such diversity means much more effort for selection, and it can take 20 years for a new variety to be launched. The first goal for achieving a hybrid potato is therefore the development of competitive diploid populations. Many features can then be adapted more easily in breeding. These include yield potential and disease resistance, as well as quality and processing properties, such as form, starch content and shelf life. “To develop genetically homogeneous and powerful parental lines for the hybrid breeding, it is also important to overcome self incompatibility of diploid potatoes and a strong inbreeding depression,” said Andreas Loock, head of sugarbeet and potato breeding at KWS. In the process, breeders can benefit from the vast amount of experience KWS has accumulated over the decades in breeding hybrids in plants such as sugarbeet and corn.

Keyword: Hybrid breeding

This breeding method developed in the USA at the beginning of the 20th century makes use of the heterosis effect. In the process, a combination of genetically different, pure-bred lines (inbred lines) leads to the increased efficiency of mixed-breed offspring, the so-called hybrids. However, the superiority of hybrids over conventional lines is largely lost in the next generation due to genetic breakdown.

Developing hybrid varieties with an excellent level of performance is very expensive: Two different line breeding programs are required for the production of inbred lines. For example, KWS cultivates corn, sugarbeet, rapeseed, rye and sunflower varieties with hybrid breeding.