Partial Resistance of Sugary Enhancer Sweet Corn Genotypes to Two Isolates of the Sugarcane Mosaic Subgroup of Potyviruses

Sweet corn genotypes containing the sugary enhancer (se) allele expressed moderate levels of resistance to maize dwarf mosaic virus (MDMV), a member of the sugarcane mosaic subgroup, under natural infection in the field in Israel. Resistance was identified both in homozygous (sese) and heterozygous (Sese) genotypes. Most (sese) genotypes developed MDMV symptoms when they were mechanically inoculated in the greenhouse. The presence of the virus was verified by ELISA analysis. Plants containing known genes for resistance did not show MDMV symptoms under natural or mechanical inoculation. Two isolates of the sugarcane mosaic virus subgroup of potyviruses, differing in virulence on sweet corn genotypes, were identified. The results show that several se inbred lines contain factors contributing to moderate field resistance to maize potyviruses, but it is not clear whether these factors are pleiotropic or are associated with the se gene. The mechanism of the resistance exhibited in conjunction with the se is not yet understood