Inheritance of Angular Leaf Spot Resistance in Common Bean and Identification of a RAPD Marker Linked to a Resistance Gene

Abstract

Angular leaf spot, caused by Phaeoisariopsis griseola (Sacc.) Ferraris, is one of the major diseases affecting the common bean ( Phaseolus vulgaris L.) in Brazil which can lead to severe yield losses. Previous studies demonstrated that cultivar MAR‐2 was resistant to race 63.39 of P. griseola . The objective of this work was to characterize the resistance to angular leaf spot in MAR‐2 in an F 2 population derived from the cross with Ruda (susceptible parent), and also to identify random amplified polymorphic DNA (RAPD) markers linked to the resistance gene. Cultivar MAR‐2 was crossed with Ruda, a “carioca‐type” cultivar susceptible to angular leaf spot, to determine the inheritance of resistance. The results demonstrated that a single dominant gene present in MAR‐2 was responsible for the resistance to P. griseola , race 63.39. Resistant and susceptible DNA bulks from the F 2 population were constructed to identify RAPD markers linked to the resistance gene. Amplification with primer OPE‐04 generated a 500‐bp fragment which distinguished the resistant from the susceptible bulk populations. Co‐segregation analysis of the entire population demonstrated that the RAPD marker was linked to the resistance gene at a distance of 5.8 Cm.