C21BM, PI 663875, R721, R821
subsp. vulgaris cv. Sugar beet
C21BM was developed from population hybrids between sugarbeet and sea beet (Beta vulgaris subsp. maritima) lines C26 (PI 610488) and C27 (PI 610489). C26 and C27 were previously released and described and are population hybrids between C37 (PI 590715) sugarbeet and B. maritima accessions collected along the North Atlantic. Three cycles of mass selection for resistance to rhizomania and virus yellows and for sugarbeet agronomic traits were run to produce line R321. Two additional cycles of mass selection for resistance to resistance breaking strain of BNYVV and sugarbeet agronomic traits were run to produce line R721. R721 was increased to produce R821 being stored as C21BM.
C21BM is approximately 50% sugarbeet and 50% B. maritima. The components of C21BM, C26 and C27, had been improved with multiple cycles of mass selection for elimination of easy bolting (annuals), for sugarbeet agronomic traits including root and crown conformation, root yield, and % sugar, and for disease resistance. Resistance selection was for rhizomania (Beet necrotic yellow vein virus), virus yellow (Beet virus yellows and Beet chlorosis virus), powdery mildew (Erysiphe polygoni), and Erwinia carotovora betavasculorum. This selection continued for five more cycles with the final two for resistance to resistance breaking strain of rhizomania (RB-BNYVV). C21BM should have genetic variability from B. maritima in a form that is easy to evaluate in standard sugarbeet variety trials. C21BM performs competively in sugarbeet variety trials for sugar yield. It is a potential source of resistance genes to existing and newly eruptive diseases of sugarbeet. C21BM is 82% rr.
|Institute||Accession number||Distribution status|
10300 Baltimore Blvd., Room 330, Bldg. 003, BARC-West, MD 20705 BELTSVILLE, United States of America
|PI 663875||Extrernal distributor|