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Registration of MNHCRR‐3,SAA, a Winterhardy Alfalfa Germplasm with Crown Rot Resistance
Author(s) -
Barnes D. K.,
Smith D. M.,
Frosheiser F. I.,
Wilcoxson R. D.
Publication year - 1990
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/cropsci1990.0011183x003000030073x
Subject(s) - germplasm , crop , biology , library science , mathematics , humanities , horticulture , agronomy , philosophy , computer science
THE MNHCRR-3 ALFALFA (Medicago saliva L.) germplasm pool was released by the USDA-ARS and the Minnesota Agriculture Experiment Station in May 1984. The MNHCRR-3,SAA (Reg. no. GP-227, PI 536528) germplasm was developed during a program to breed for crown rot resistance. About 5500 2-yr-old plants from 110 cultivars were evaluated for crown rot in a study at Rosemount, MN in 1972. About 110 crown-rot-free plants were identified. Intercrossed seed was produced on 82 plants from winterhardy cultivars and bulked to form MNHCRR-1 (1). MNHCRR1 was replanted in the same field at Rosemount, MN in May 1973. When the plants were 2-yr old about 150 plants free of crown rot were selected from about 3600 plants and intercrossed to produce MNHCRR-2. Several thousand plants of MNHCRR-2 were screened for resistance to Phytophthora root rot [caused by Phytophthora megasperma (Drechs.) f. sp. medicaginis Kuan and Erwin] at St. Paul, MN. About 150 resistant plants were intercrossed to produce MNHCRR-3. One thousand plants of MNHCRR-3 were space-planted in Fresno, CA, and 100 plants showing field resistance to the spotted alfalfa aphid [Therioaphis maculata (Buckton)] were intercrossed to produce MNHCRR-3,SAA. MNHCRR-3 and MNHCRR-3,SAA have performed similarly in agronomic and disease resistance tests. MNHCRR3,SAA is winterhardy with fall growth habit similar to that of 'Ranger'. The percentage of plants resistant to bacterial wilt (caused by Clavibacter michiganense subsp. insidiosum Davis) in a field test at Rosemount, MN was MNHCRR3,SAA = 45, 'Vernal' (resistant check) = 42 and 'Narragansetf (susceptible check) = 4. The percentage of plants resistant to Fusarium wilt [caused by Fusarium oxysporum f. sp. medicaginis (Weimer) Snyd. & Hans.] in a field test at Rosemount, MN was MNHCRR-3,SAA = 44, 'Agate' (resistant check) = 54, and MNGN-1 (susceptible check) = 6. The percentage of plants resistant to Phytophthora root rot in a field test at St. Paul, MN was MNHCRR-3.SAA = 17, Agate (resistant check) = 43, and 'Saranac' (susceptible check) = 0. MNHCRR-3,SAA yielded 104% of Vernal after 5 yr and 107% of Vernal after 3 yr in two forage yield trials at Rosemount, MN. It has maintained better stands than Vernal and most other cultivars in long-term yield trials. Fifteen grams of Syn 2 seed will be made available to each applicant upon written request. It is requested that appropriate recognition be given to the source of this germplasm when it contributes to the development of a new cultivar or hybrid. Request seed from D.K. Barnes, Department of Agronomy and Plant Genetics, University of Minnesota, 411 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108.