Identification of anthracnose resistance genes in dry bean cultivars grown in Manitoba

Abstract

Previously described random amplified polymorphic DNA (RAPD) and sequence characterized amplified region (SCAR) markers were used to identify specific genes for anthracnose resistance in 20 dry bean (Phaseolus vulgaris) cultivars and one breeding line. These included six navy bean, five black bean, three kidney bean, two great northern bean, two pinto bean, one cranberry bean, one pink bean and one small red bean cultivars. The reactions of these bean cultivars to five races (i.e., races 23, 31, 73, 81, 105) of Colletotrichum lindemuthianum were used to verify the results of the molecular marker tests. The combined analysis of genotypes estimated with markers and race reactions showed that navy bean cultivar Envoy carried gene Co-12, possibly in combination with other resistance genes, which conferred resistance to all the races except race 105. The bean cultivars Morden003, Messina and CDC Nordic carried Co-15, which provided resistance to only races 73 and 105. Resistance in AC Mariner appeared to be controlled by gene Co-2 either alone or possibly in combination with Co-11. The kidney bean cultivars Chardonnay and ROG 802 carried resistance gene Co-1. Eight other cultivars were resistant to races 23 and 31, which indicated that they carried resistance gene Co-3 or another unidentified resistance gene. Six dry bean cultivars were susceptible to all five anthracnose races. Genotype estimates were based primarily on the virulence pattern of the races on specific cultivars. The results from the molecular tests sometimes supported the proposed genotypes based on the results from the race inoculations, but false positive results often occurred with molecular markers for genes Co-2 and Co-4. Virulence pattern information allowed the detection of specific resistance genes in certain cultivars, but did not always rule out the presence of other genes.