997 USE OF MOLECULAR MARKERS IN BREEDING FOR RESISTANCE TO FUNGAL PATHOGENS

Abstract

The use of RAPD markers in disease resistance breeding has been successfully demonstrated in horticultural crops. The identification of RAPD markers and their potential role in disease resistance breeding was first demonstrated in tomato; the procedure of bulk segregant analysis for detecting linkages between RAPD markers and genes conditioning resistance to downy mildew was described in lettuce; the use of linked RAPD markers to facilitate the efficient pyramiding of epistatic rust resistance genes to prolong their durability has been illustrated in common bean; the development of allele specific or sequence characterized primers linked to resistance genes has been achieved in pea, bean, tomato, and lettuce Indirect selection for disease resistance based on molecular markers is not a replacement for classical breeding procedures. Used as tools, markers offer breeders unique opportunities to combine resistance to an array of different pathogens and efficiently pyramid epistatic resistance genes for highly variable fungal pathogens. This would not always be possible in the absence of linked markers.