Badger Beat A New Beginning—Producing Diploid Potato Seed
Breeding program conducts seed multiplication trial in anticipation of developing diploid potato varieties By Paul Bethke, Andy Hamernik and Jeff Endelman
Seed potatoes are the foundation of the potato crop and
are likely to retain that essential position for many years. However, there is interest in exploring how transplants produced from true potato seed might be incorporated into early generation tuber seed production. True seeds are found in potato berries. Berries, also called fruit, are produced when flowers are pollinated. Bumblebees pollinate potato flowers in the field, but controlled hand pollination by humans works very well and is used in greenhouses. Potato breeders have used this approach for decades to generate the seeds that lead to new varieties. Several potato breeding programs in the United States, Europe and Asia are trying to develop genetically simpler diploid potato varieties. Diploid potatoes, which have their genetic information on two sets of chromosomes, are attractive to breeders because genetic manipulations are much easier than with our current tetraploid varieties that have four sets of chromosomes. This, in turn, is expected to result in faster rates of variety improvement
and opportunities for enhancing, rather than replacing, a diploid variety. A key breeding goal for diploid potatoes is production of diploid hybrid varieties. These varieties would result from cross-pollination between two diploid parents. The resulting hybrid seeds would be the new variety. We are very familiar with corn and
Above: Transplants grown from true potato seed are ready for transport.
tomato varieties, for example, that are produced this way. For potato, however, the approach is very unfamiliar, and it is reasonable to wonder how it could work. TRUE POTATO SEED Paul Mitchell and co-authors, in the August 2022 Badger Common’Tater, looked at the economics of seed potato production and how true potato seed might be incorporated into the process. In this article, we will describe greenhouse and field activities that illustrate one way this might occur in practice. The benefits of true potato seeds will be highlighted, but no more than the challenges and disappointments we’ve encountered. To begin with, it might be best to review some of the activities that take place during the early phases continued on pg. 60
First field year seed tubers produced by transplants were used as seed the following year. As seen in this photo, rows planted from seed tubers in the >50 grams size category (front right) have full canopy coverage, but rows planted with seed tubers in the 10-gram size category (middle left) have not yet filled the rows. The photo was taken on July 7, 2023. BC�T September 59