Inheritance of resistance to blackeye cowpea mosaic and cowpea aphid-borne mosaic viruses in Phaseolus vulgaris

In populations from crosses of resistant and susceptible plants of the bean (Phaseolus vulgaris) cultivar Black Turtle Soup, resistance to blackeye cowpea mosaic virus (BICMV) and to cowpea aphidborne mosaic virus (CAbMV) was conferred independently by single dominant factors that appear to be closely linked. The symbol Bcm was assigned to the gene for BICMV resistance and Cam to that for CAbMV. Linkage was determined by separately inoculating plants of the testeross with both viruses on different leaves. Since BICMV and CAbMV Incite identical symptoms, but do not cross protect against each other, their presence in each susceptible plant was determined by enzyme-linked immunosorbent assay (ELISA). This detection method was highly specific because the two viruses are distantly related serologically. The normally resistant plants responded with a lethal systemic hypersensitive reaction when approach-grafted to BICMV or CAbMV-infected plants, or when mechanically in oculated and held constantiy at 35°