Registration of sugar beet mapping populations CN239, CN240, and CN241 segregating for resistance to Heterodera schachtii from sea beet

Abstract

AbstractSugar beet (Beta vulgaris L.) mapping populations CN239 (Reg. no. MP‐1, NSL 540835 MAP), CN240 (Reg. no. MP‐2, NSL 540836 MAP), and CN241 (Reg. no. MP‐3, NSL 540837 MAP) segregate for sugar beet cyst nematode (SBCN) resistance and were developed by the USDA‐ARS at Salinas, CA. Our first objective was to compare soil for greenhouse screening: naturally infested (SBCN‐infested field) and artificially inoculated (pasteurized with Heterodera schachtii cysts added). Commercial and USDA‐ARS lines were grown in each diluted to 20 cysts g−1. Each was rinsed to collect cysts. The USDA‐ARS lines were kept until cyst counts were completed, in preparation for the second objective: make crosses with individuals of known SBCN reaction. A beet plant can have thousands of flowers, making traits heterogenous. For genetic studies, resistance must be confirmed prior to crossing, or progeny could have unexpected segregation. 7927‐4‐308D seedlings with low cyst counts (2–17 cysts) were selected as the SBCN‐resistant donor parent in mapping populations CN239, CN240, and CN241. 7927‐4‐308D resistance is derived from composite crosses between sugar beet and over 40 Beta vulgaris subsp. maritima (L.) Arcang. accessions. CN239 combined 7927‐4‐308D with 0747 (elite line) plants with high counts (115–148 cysts). CN240 combined 7927‐4‐308D with CN12‐446 (SBCN resistant) plants with low counts (11–26 cysts). Allelism between 7927‐4‐308D and CN12‐446 is undetermined. CN241 combined 7927‐4‐308D with a 7927‐4‐309E plant with high count (54 cysts). 7927‐4‐309E is a sister line of 7927‐4‐308D but is SBCN susceptible.