Issue link: http://read.uberflip.com/i/974994
24 POTATO GROWER | MAY 2018 Diggin' In Diggin' In Diggin' In Diggin' In Diggin' In Diggin' In INSECTS | By Helen H. Tai, Benoit Bizimungu, Chandra Moffat & Kyle Gardner Breeding potatoes that are not tasty—to Colorado potato beetles Yuck! Colorado potato beetle is major pest of cultivated potato, in many instances causing 30 to 50 percent losses in tuber yield. Both the larval and adult stages of the beetle feed on potato leaves, and an infestation can lead to defoliation of the crop in a matter of days. Control of the beetle has involved use of neonicotinoid insecticides, particularly imidacloprid. However, there is concern that beetle populations are developing resistance and that neonicotinoids may have unintended effects on beneficial insects, which has made finding alternatives to insecticides a priority. While Colorado potato beetles feed voraciously on the leaves of the potato plant, the beetles will avoid feeding on some wild relatives of potato in the Solanum genus. Yvan Pelletier, a retired entomologist at Agriculture and Agri-Food Canada (AAFC), and his team spent many years screening wild Solanum plants in fields naturally infested with Colorado potato beetle to identify resistant species. AAFC geneticist David De Koeyer and retired breeder Hielke De Jong cross-pollinated wild Solanum plants with domesticated potato to produce hybrid crosses with increased Colorado potato beetle resistance. Benoit Bizimungu and Agnes Murphy, potato breeders at AAFC, evaluated resistant progenies in multiple generations in fields and laboratories, testing to identify adapted lines with improved agronomic and processing traits. Resistant selections are progressing through various stages of the potato breeding program; the first generation was released in the AAFC accelerated release program in 2016. In potato, cross-pollinations mix half the genetic material from one parent with half the genetic material from the other parent to form the embryo in true botanical seed. The problem is, each parent does not always contribute the same half of its genetic material. It is like shuffling cards: A different half is contributed in each pollen grain and egg cell. This means that each of the seeds has a different shuffle of genetic material contributed from each of the parents. The plants that grow from these true seeds have a unique genetic combination of the parents. In the AAFC breeding greenhouse in Fredericton, New Brunswick, 100,000 seeds are planted annually from hundreds of crosses of pairs of parents. It is the job of the breeder and the breeding team to find the gems among these plants that have the right combination of Researchers are hoping to breed potato varieties whose leaves will be less appetizing to the often devastating Colorado potato beetle.