Registration of Sugar Beet Germplasm Lines CN921‐515 and CN921‐516 with Sugar Beet Cyst Nematode Resistance from Beta vulgaris subsp. maritima

Abstract

CN921‐515 (Reg. No. GP‐295, PI 669447) and CN921‐516 (Reg. No. GP‐296, PI 669448) sugar beet (Beta vulgaris L.) germplasm lines, with sugar beet cyst nematode (SBCN) resistance derived from Beta vulgaris subsp. maritima L. (Bvm), were developed and released by the USDA‐ARS at Salinas, CA, in cooperation with the Beet Sugar Development Foundation in Denver, CO. CN921‐515 and CN921‐516 are multigerm, green hypocotyl, self‐fertile, partially inbred lines extracted from genetic‐male‐sterile facilitated, random‐mated lines. Greenhouse SBCN screening of individual plants and progeny tests indicate each is likely homozygous resistant. CN921‐306 is the progenitor population and was developed from multiple composite crosses involving >40 Bvm accessions. Therefore, the original wild beet accession that contributed sugar beet cyst nematode resistance to these lines is not known, nor are the allelic relationships with recently released CN12‐446, CN12‐770, and CN72‐652. CN921‐515 and CN921‐516 have a higher frequency of SBCN resistance (higher number of resistant individuals per line) than CN921‐306. CN921‐515 and CN921‐516 also have an increased number of rhizomania‐resistant individuals compared with CN921‐306.