Development of SCAR markers linked to powdery mildew (Uncinula necator) resistance in grapevine (Vitis vinifera L. and Vitis sp.)

Sequence-characterized amplified regions markers (SCARs) were developed from six randomly amplified polymorphic DNA (RAPD) markers linked to the major QTL region for powdery mildew (Uncinula necator) resistance in a test population derived from the cross of grapevine cultivars Regent (resistant) x Lemberger(susceptible). RAPD products were cloned and sequenced. Primer pairs with at least 21 nucleotides primer length were designed. All pairs were tested in the F1 progeny of Regent x Lemberger. The SCAR primers resulted in the amplification of specific bands of expected sizes and were tested in additional genetic resources of resistant and susceptible germplasm. All SCAR primer pairs resulted in the amplification of specific fragments. Two of the SCAR markers named ScORA7-760 and ScORN3-R produced amplification products predominantly in resistant individuals and were found to correlate to disease resistance. ScORA7-760, in particular, is suitable for marker-assisted selection for powdery mildew resistance and to facilitate pyramiding powdery mildew resistance genes from various sources.