INHERITANCE OF THE MOSAIC AND NECROSES REACTIONS INDUCED BY BEAN SEVERE MOSAIC COMOVIRUSES IN PHASEOLUS-VULGARIS L

The inheritance of the localized necrosis, apical necrosis, and mosaic reactions induced by bean severe mosaic comoviruses in common bean (P haseolus vulgaris L.), was studied in crosses of Great Northern 123 x Pitouco, Great Northern 123 x Iguacu and Pitouco X Iguacu. Great North ern 123 reacts with mild mosaic, Iguacu with localized necrosis, and P itouco with apical necrosis to bean severe mosaic comoviruses. The ana lysis of the F-1 and F-2 generations indicated that localized necrosis was dominant over mild mosaic, and apical necrosis was dominant over the localized necrosis and the mild mosaic. An independently inherited single dominant gene controlled the expression of localized and apica l necrosis in cultivars Iguacu and Pitouco, respectively. The dominant gene for apical necrosis (Any) found in Pitouco, was epistatic over t he dominant gene (Lnv) conditioning localized necrosis in Iguacu, as s uggested by the F-2 of Pitouco x Iguacu, that yielded a ratio of 12 ap ical necrosis: 3 localized necrosis:1 mild mosaic. The genotypes of Pi touco, Iguacu and Great Northern 123 are: Anv Anv lnv lnv, anv anv Lnv Lnv, and anv anv lnv lnv, respectively.