Germplasm Release: Tissue Culture-Derived Curly Top-Resistant Genetic Stock

The USDA-ARS sugarbeet research program at Kimberly is focused on discovering novel genes for resistance to beet curly top and other economically important diseases. It is vital in genetics research to develop uniform breeding lines and genetic stocks to study inheritance, gene transfer (through conventional hybridization), and molecular genetics research. This process requires several one-year inbreeding cycles in sugarbeet because the plant is biennial and the public germplasm has much genetic diversity. We have adopted a well-established tissue culture approach to develop a type of pure breeding lines called ‘doubled haploid line’ (DHL) from unfertilized ovules. KDH13 (PI663862) genetic stock was released to public breeders and seed companies by the USDA-ARS Kimberly sugarbeet program, in cooperation with the Beet Sugar Development Foundation .This principal investigator has been deposited at the Western Regional Plant Introduction Station (WRPIS) in Pullman, WA. KDH13 is the first publically available sugarbeet genetic stock that is highly resistant to curly top. It has performed better than the curly top resistant check, Hilleshog PM90, in two greenhouse experiments (9 replications per treatment and 6 leaf hoppers per plant in a clip-cage) and same as the resistant check in the 2011 Curly Top Nursery in Kimberly, ID. This breeding line is currently used to develop beet leafhopper populations that carry a single virus species. Having a genetically uniform line eliminates the normal genetic variation between plants when we are testing for specific virus species. KDH13 is monogerm, self-fertile, and highly resistant to bolting. It has light green, upright, narrow leaves, and a small compact canopy. It’s susceptible to rhizomania, caused by the beet necrotic yellow vein virus (BNYVV), and powdery mildew (caused by Erysiphe polygoni). KDH13 can be an ideal donor of curly top resistance in hybrids, or used for backcrossing and inheritance studies of other economically important traits. The initial sugarbeet ovule culture work was performed under contract by a private company