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Registration of UC 193 Alfalfa Germplasm with High Resistance to Downy Mildew and Fusarium Wilt
Author(s) -
Lehman W. F.,
Stuteville D. L.,
Marble V. L.
Publication year - 1988
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/cropsci1988.0011183x002800030041x
Subject(s) - germplasm , downy mildew , fusarium wilt , library science , biology , horticulture , mildew , fusarium oxysporum , computer science
UC 193 (Reg. no. GP-202) (PI 512289) alfalfa (Medicago sativa L.) germplasm was released by the Department of Agronomy and Range Science, University of California, Davis, and the Department of Plant Pathology, Kansas State University, Manhattan, in July 1987. UC 193 is a nondormant germplasm with high resistance to downy mildew (caused by Peronospora trifoliorum d By.) and Fusarium wilt (caused by Fusarium oxysporum Schlecht. f. sp. medicaginis (Weimer) Snyd. and Hans.), and low resistance to anthracnose (incited by Colletotrichum trifolii Bain). UC 193 was selected from UC 143 (2) for resistance to downy mildew isolate 1-7 from Kansas, isolate 1-8 from El Centro, CA, and a virulent mixed culture from Thomas County, KS. UC 143 parentage traces to UC 123 (2), which was selected from 'CUF 101' (1). At the seedling stage, 20 138 UC 143 plants were screened for resistance to downy mildew. The survivors were then selected for resistance to anthracnose race 1. The 216 plants that were resistant to both diseases were placed in a cage at El Centro, CA, and pollinated by honeybees (Apis mellifera L.) to produce Syn 1 seed of UC 193. Mean percentages of seedlings free of mildew after inoculation with downy mildew isolates 1-7 and 1-8, respectively, were UC 193, 73.2 and 75.0; 'Saranac' (resistant), 18.2 and 46.2; and 'Kanza' (susceptible), 2.0 and 1.5. Mean percentages of plants resistant to anthracnose (race 1) were UC 193, 12.1; 'Arc' (resistant), 75.6; and Saranac (susceptible), 3.7 (3). Resistance evaluation tests for Phytophthora root rot (caused by Phytophthora megasperma Drechs. f. sp. medicaginis Kuan and Erwin) and Fusarium wilt were conducted at St. Paul, MN (4). Mean percentages of plants resistant to Phytophthora root rot were UC 193, 11.6; 'Agate' (resistant), 35.4; and Saranac (susceptible), 4.9. Mean percentages of plants resistant to Fusarium wilt were UC 193,94.7; 'Moapa' (resistant), 89.6; and 'Narragansett' (susceptible), 38.6. In hay production tests, UC 193 produced 84% of CUF 101 at El Centro, CA, in a 2-yr test, and 115% of CUF 101 at Five Points, CA, in a 5-yr test. Resistance to the blue alfalfa aphid (Acyrthosiphon kondoi Shinji) is similar to CUF 101 (1). Five grams of seed of UC 193 will be distributed upon written request and agreement to make appropriate recognition of its source as a matter of open record when this germplasm contributes to the development of a new cultivar, hybrid, or germplasm. Requests for seed should be directed to Dr. W.F. Lehman, University of California, 1004 E. Hoiton Road, El Centro, CA 92243.