Dept. of Horticultural Sciences
Dept. of Plant Pathology
Cornell University, Geneva, NY 14456, USA

Marker-assisted selection permits rapid pyramiding of specific genes in crop breeding. In pea, markers have been described for er1 (conferring resistance to powdery mildew), En (conferring resistance to pea enation mosaic virus), the mo cluster of genes (conferring resistance to bean yellow mosaic virus, clover yellow-vein virus, pea mosaic virus, the lentil strain of pea seedborne mosaic virus and the NL8 strain of bean common mosaic virus), and sbm1 (conferring resistance to strains PSbMV-ST, PSbMV-L, PSbMV-P4 of pea seedborne mosaic virus, watermelon mosaic virus 2, clover yellow-vein virus and white lupin mosaic virus). We have used some of these markers to combine these genes in lines that are also resistant to fusarium wilt races 1 and 2.

A breeding line from the program of the late Prof. G.A. Marx, B880-221 (er1, Fw, Fnw) was crossed with OSU1026 (er1, Fw, En, sbm1, mo). F2 plants were screened for segregation of the markers B500400 and B3021300 to eliminate individuals lacking En or mo. Five F3 plants from the remaining lines were screened for directly for resistance to pea seedborne mosaic virus and by marker for homozygosity for Fnw, En and mo. Lines proving homozygous at all four loci were examined in the field during the summer of 1998 for vigor and production. Those giving good seed set were selected as potentially valuable breeding material. The best performing lines included: A98-13 #5-1, 32-1, 41-1, 53-2, 78-2, 83-2, and 85-3. Small amounts of seed from each of these lines are available upon request.