title: Screening apples for OPD20/600 using sequence-specific primers.
abstract: Apple scab, caused by Venturia inaequalis (Cke.) Wint., is the most serious disease of apple trees in many areas of the world. Resistance to V. inaequalis, derived from the small-fruited species Malus floribunda 821, is determined by a major dominant gene, Vf. Using random decamer primers, we identified a RAPD marker, OPD20/600, which is linked to the Vf gene. OPD20/600 was then cloned and sequenced. Sequence-specific primers based on the marker were used to further screen M. floribunda 821, 7 scab-susceptible apple cultivars, 10 scab-resistant apple cultivars, and 28 scab-resistant Coop selections. The sequence-specific primers allowed identification of polymorphisms of OPD20/600 based on the presence or absence of a single band. The advantages of sequence-specific primers over decamer primers for developing genetic markers are discussed.
authors.affiliation: Department of Horticulture, University of Illinois, 310 Madigan Bldg., 1201 W. Gregory Drive, 61801, Urbana, IL, USA.
authors.forename: H
authors.initials: H
authors.lastname: Yang
authors.forename: S S
authors.initials: SS
authors.lastname: Korban