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Inheritance of Resistance to Phytophthora megasperma in Diploid Alfalfa 1
Author(s) -
Irwin J. A. G.,
Maxwell D. P.,
Bingham E. T.
Publication year - 1981
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/cropsci1981.0011183x002100020017x
Subject(s) - biology , ploidy , phytophthora megasperma , medicago sativa , phytophthora , medicago , resistance (ecology) , root rot , botany , inheritance (genetic algorithm) , phycomycetes , epistasis , horticulture , genetics , agronomy , gene , inoculation
Few genetic studies have been made to determine the inheritance of disease resistance in diploid alfalfa ( Medicago sativa L.). The objectives of this study were to determine the inheritance of resistance to Phytophthora root rot in Wisconsin cultivated diploid alfalfa (CADL) and in diploid Medicago coerulea Less. (PI 299046). S 1 populations and F 1 populations from crosses of resistant and susceptible plants of CADL were generated, and their segregations for disease reaction indicated that resistance was conditioned by two dominant complementary genes, designated Pm 1 and Pm 2 . The observed segregations in S 2 F 2 testcross families of CADL provided additional evidence to support this model. Segregations for resistance to Phytophthora root rot in S 1 , F 1 and F 2 families from intercrosses of two resistant Medicago coerulea plants and two susceptible CADL plants indicated that resistance in M. coerulea was complex, and that epistatic relationships might be of importance. These studies indicate the potential usefulness of diploid alfalfa as new sources of resistance to Phytophthora root rot.