Submitted to: Germplasm Release
Publication Type: Germplasm Release
Publication Acceptance Date: June 12, 2004
Publication Date: February 17, 2005
Citation: Panella, L.W., Hanson, L.E. 2005. Notice of Release of FC720, FC722, and FC722CMS Monogerm Sugar Beet Germplasm. Germplasm Release. 02/17/2005. Interpretive Summary: This is a Germplasm Release no interpretive summary is required.
Technical Abstract: FC720 has good resistance to root-rotting strains (AG-2-2) of Rhizoctonia solani Kühn and good to moderate resistance to cercospora leaf spot caused by Cercospora beticola Sacc., but is not resistant to the Beet curly top virus (BCTV). FC722 has good resistance to root-rotting strains (AG-2-2) of Rhizoctonia solani and good to moderate resistance to cercospora leaf spot caused by Cercospora beticola, but is BCTV susceptible. FC720 and FC722 are populations from which to select rhizoctonia and cercospora resistant, monogerm, O-type parents to infuse some rhizoctonia and leaf spot resistance on the female side of hybrids, and FC722CMS provides a CMS female with these characteristics. FC720 is an O-type germplasm with 73% green hypocotyls and is segregating for monogerm and self-sterility. FC722 is an O-type germplasm with 15% green hypocotyls and is segregating for monogerm and self-sterility. Both germplasm have FC708 (PI 590845), a rhizoctonia- and cercospora-resistant monogerm O-type release from the Fort Collins program as one parent. The other parent, C718 (PI 590849), is a germplasm released from the USDA-ARS sugarbeet improvement program in Salinas, CA, and is moderately susceptible to virus yellows, moderately resistant to bolting, and moderately resistant to BCTV; it has very good combining ability for root and gross sugar yield. FC720 is a product of six generations of mass selection for rhizoctonia resistance among progeny of the cross combination (C718 //(C718/FC708)). FC722 also is a product of six generations of cyclic mass selection for rhizoctonia root rot resistance. The source population was the cross C718/FC708; and FC722CMS is the genetic-cytoplasmic male sterile equivalent of FC722 backcrossed nine times. FC720, FC722, and FC722CMS's performance was equal to the rhizoctonia-resistant check in disease index (DI) ratings, except in 1999 when FC722CMS was significantly less resistant than the resistant check (FC703), but significantly more resistant than the susceptible check (FC901/C817). FC720, FC722, and FC722CMS always performed significantly better than the susceptible check. In three years of testing (1998 1999, 2002) for resistance to cercospora leaf spot , they were significantly better than the susceptible check, and not significantly different from the resistant check, except for FC722, which had significantly less resistance than the resistant check in 1999). Sucrose concentrations of FC720, FC722, and FC722CMS, respectively, were 86.0%, 70.2%, and 76.3% of the standard (mean of Beta 6045, HM1955, Monohikari), and in sugar loss to molasses, FC720, FC722, and FC722CMS were 113.3%, 114.9% and 123.7%, respectively, of the standard.