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Research Genetic Linkage Between Mex2, a Specific Resistance Gene to
Anthracnose, and Anp, a Gene Involved in Pod Anthocyanin Accumulation in
Bean. Pascal Gantet, ORSAN Pre-Graduate Fellow, Priscilla Bettini, EEC-BAP
Postdoctoral Grantee; Jeanine Grisvard, Maître de Conférences; and Michel Dron,
Professor, Departement de
Biologie Moléculaire Végétale, URA CNRS 1128, Bâtiment 430, Université Paris
Sud, 91405 Orsay, France. Plant Dis. 75:941-942. Accepted for publication 26
February 1991. Copyright 1991 The American Phytopathological Society. DOI:
10.1094/PD-75-0941. Breeding tests in bean (Phaseolus vulgaris) with Mex2, a single
dominant resistance gene to bean anthracnose, suggested a linkage between this
gene and pod anthocyanin accumulation. The cross between an inbred, purple-pod,
anthracnose-resistant cultivar with Mex2 (AFN) and an inbred, green-pod,
susceptible cultivar (La Victoire) was performed to study the segregation of the
two characters and to recover green pod progeny resistant to Mex2,
because purple pods are commercially unacceptable. Pod anthocyanin accumulation
proved, at least in this cross, to be under the control of a single, dominant
Mendelian gene, which has been designated Anp (anthocyanins in the pod).
Among 548 plants of F<sub>2</sub> progenies, 13 recombinant phenotypes were
identified. The genetic distance between Mex2 and Anp was
estimated by maximum likelihood analysis to be 2.3 ± 1.3 cM (95% CI). |