|Ruppel, Earl - RETIRED; USDA-ARS|
|Hecker, Richard - RETIRED; USDA-ARS|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 31, 1997
Publication Date: N/A
Interpretive Summary: Sugarbeet germplasms FC716 through FC719 (multigerm, pollinators) were developed as sources of resistance to root-rotting strains of Rhizoctonia solani. Some of these germplasms are moderately tolerant to Cercospora leaf spot, induced by Cercospora beticola, and have low to medium resistance to curly top virus. In replicated, innoculated field experiments, these germplasms were not significantly different from each other or from a resistant check, but were significantly better than the susceptible check. FC716 through FC719 are proposed for use as diverse multigerm populations from which to select multigerm pollinator, O-type monogerm, and CMS female parents for use in commercial three-way resistant hybrids.
Technical Abstract: Each of these germplasms was developed from genetically different and distinctive sources. These lines should provide resistance to root-rotting strains (AG-2-2) of Rhizoctonia solani Kuhn and potential pollinators with combining ability for yield. FC716 resulted from interpollination of 38 mother roots, which were selected for resistance to Rhizoctonia from three commercial hybrids, HH32 (66%), ACH-139 (24%), and 70MSH386 (10%). This initial population underwent five cycles of mass selection for Rhizoctonia root rot resistance. FC716 has excellent Rhizoctonia root rot resistance when tested under strong disease pressure and it should have potential as a source of Rhizoctonia-resistant germplasm with high combining ability for sugar yield. FC717 was derived from a cross between FC708 and ACH14. Starting with the F2 population, four cycles of mass selection for Rhizoctonia resistance were made and it has excellent Rhizoctonia root rot resistance when tested under strong disease pressure. It has low-medium Cercospora leaf spot resistance and is susceptible to curly top virus. FC717 is diploid, multigerm, and has medium sucrose content. It is segregating for green hypocotyl (17%). FC718 resulted from the interpollination of Rhizoctonia resistant selections from four USSR open-pollinated populations Ramonsk 06 (5 plants), Ramonsk 100 (2plants) Verkhynyachsk 072 (1 plant), and Vladovsk 20 (1 plant). The initial population of FC718 underwent eight cycles of mass selection for Rhizoctonia root rot resistance. FC718 has excellent Rhizoctonia root rot resistance when tested under strong disease pressure. FC718 is susceptible to Cercospora leaf spot and curly top. FC718 is diploid and multigerm.