[Although this extensive article by Marcel Bruins was originally published by European Seed in 2018, I believe it to be as relevant and topical today as it was then, and I decided to publish a very brief summary of part of it here with a link to the full article. – Lukie]
European Seed sat down with some of the major potato breeding companies in Europe to learn more about the challenges and opportunities of breeding new potato varieties. Piet Smeenge, Director of Kweekbedrijf Smeenge-Research, Vanessa Prigge, Project Manager Crop Improvement at Solana, Gerard Backx, CEO of HZPC, Jan-Paul Bandsma, Product Manager at de Nijs Potatoes, and Guus Heselmans, Manager R&D of C. Meijer B.V. provided insight on this heavily favoured crop.
Smeenge states that potato-breeding takes a lot of time as there can be only one selection per year. He says in total it takes 10-12 years before protection and listing. “With seed-crops, hybrid breeding is possible, so there you only need a few years for creating new varieties. In potato, hybrid-breeding is (still) not possible, however, KWS, Solynta, HZPC and Bejo are working on it. So maybe it will be possible in the coming 10 years.”
Backx concurs, indicating that the multiplication rate of a vegetatively propagated crop is much slower, making the selection process slower and the introduction phase longer. “Hence, much more years are required.”
He says on the other hand, the maintenance of the genetics is simple as the genetics do not change. In general, vegetatively propagated crops have a much more complex genome, which is the biggest hurdle.
“Potato is tetraploid and enormously heterogeneous. Working with diploid plants is possible, but so far this is only done in a research phase. Apart from that, double haploids might be an option, but not an easy route.”
The main challenges associated with the vegetative nature of potato production are the low multiplication rate and the high risk of transmission of tuber-borne diseases.
Prigge says in maize for example, with the seeds of one single testcross ear you can sow yield trials in several locations, even in replicated designs, already in the first field year. In potato in contrast, it easily takes beyond the fourth field year to reliably assess tuber yield performance in a similar experimental design due to the low multiplication rate of less than 15 tubers per plant which means that the first years are dedicated to tuber production for testing purposes.
For Prigge, the relevance of a disease for the potato breeding programme depends on the anticipated market. “For example, at the moment resistance to the white nematode Globodera pallidais in high demand for varieties for European farmers, no matter what market segment. New and highly virulent nematode strains have been found which had overcome resistance of the commonly used resistant varieties. …We did the same for Late Blight or Root Knot Nematode resistance, because little genetic variation for resistance against these diseases was available in the European potato varieties.”
She says in other diseases such as Blackleg there is hardly any breeding possible because “we lack the prerequisites for breeding progress: genetic variation and an efficient and reliable phenotyping system.
Heselmans shares that in principle the goal is same as in any crop: combine positive traits to retrieve genetic gain. In case of potatoes to be marketed as vegetative crop there are no hurdles like inbreeding to reach homozygosity. This hurdle has to be taken in case route of F1-hybrid true potato seed (TPS) breeding is chosen.
“Clonal multiplication of potatoes does require more time (factor 8-10) compared to true seed F1 hybrids. Overall, complexity of genetics of the nowadays cultivated potato is a challenge due to its tetraploid and heterozygote nature, this applies for whole field of potato breeding,” he says
According to Smeenge, nematodes and then especially the two species Globodera rostochiensisand G. pallidaare the most important pests. He draws his genetic diversity from starch-varieties, from the gene-bank at Wageningen University (WUR), and from his own breeding lines.
“Second is late blight and we get our diversity from the Louis Bolk Institute through the ‘Bio-Impuls’ Program, and his own breeding material. And third: common scab and virus. Diversity comes from his own breeding program which is already in existence for more than 45 years.”
Read this wide ranging and extensive article on European Seed here