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Registration of Rhizoctonia Root Rot Resistant Sugarbeet Germplasms FC 701/6, FC 702/7, and FC 705/1
Author(s) -
Hecker R. J.,
Ruppel E. G.
Publication year - 1985
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1985.0011183x002500020063x
Subject(s) - rhizoctonia , geneticist , biology , library science , germplasm , root rot , horticulture , botany , rhizoctonia solani , computer science , genetics
SUGARBEET (Beta vulgaris L.) germplasms FC 701/6 (Reg. no. GP-91), FC 702/7 (Reg. no. GP-92), and FC 705/1 (Reg. no. GP-93) were developed and jointly released by USDA-ARS in cooperation with the Beet Sugar Development Foundation and the Colorado State University Experiment Station. These germplasms were developed as sources of resistance to root rot caused by Rhizoctonia solani Keuhn. The three germplasms are diploid (2 X = 18), multigerm, pollen fertile, self sterile, relatively easy bolting, heterogeneous for hypocotyl color, and moderately resistant to Cercospora beticola. The ancestry of all three ultimately traces to a genetically broad based cultivar 'GW359.' FC 701/6 resulted from three cycles of mass selection (MS) for resistance, one cycle of selection based on progeny testing for resistance and high general combining ability (GCA) for sucrose yield, followed by two additional cycles of MS for resistance. Selection originated from FC 701, a moderately resistant germplasm (1) that had been developed from the obsolete open-pollinated susceptible heterogeneous cultivar GW674. Each generation involved 30 or more plants. FC 702/7 resulted from three cycles of MS for resistance, one cycle of selection based on progeny testing for resistance and high GCA, followed by three cycles of MS for resistance. Selection originated from FC 702, a moderately resistant germplasm (1) that had been developed from a high-producing susceptible experimental synthetic variety. Each generation involved 12 or more plants. FC 705/1 resulted from nine cycles of MS for resistance, and two cycles of recurrent selection with progeny testing for resistance and high GCA. Selection originated from a sib-line of FC 701 (1), and never involved fewer than 20 plants per generation. In 3 years of testing under artificially created epiphytotics, FC 701/6, FC 702/7, and FC 705/1 had mean disease indices (DI) of 2.3,2.4, and 2.0, respectively, compared with 3.0 for the resistant check, FC 703 (2), and 5.7 for the susceptible check (scale of 0-7). All three of the germplasms have shown good GCA for sucrose yield. They are relatively vigorous. These germplasms were released for use as resistant pollinators, or as sources for development of resistant pollinators, in the breeding of Rhizoctoniaresistant hybrids by sugarbeet breeders. Breeder seed is maintained by USDA-ARS, and will be provided to sugarbeet breeders in quantities adequate for reproduction. It is asked that appropriate recognition be made of the source when one of these germplasms contributes to the development of a new cultivar, hybrid, or breeding line. Written requests for seed should be made to Sugarbeet Production Res., USDA-ARS, Crops Res. Lab., Colorado State Univ., Fort Collins, CO 80523.