Resistance genetic basis of a wild tomato access to pepper yellow mosaic virus

Abstract

The aim of this work was to evaluate the genetic basis of resistance of Lycopersicon hirsutum to the potyvirus Pepper yellow mosaic virus (PepYMV). Five hundred and forty plants, including the parentals 'Santa Clara' (susceptible) and 'BGH 6902' (resistant) were evaluated, as well as the generations F₁, F₂, RC_1:1 and RC_1:2, from the crossing of the above parentals. PepYMV was mechanically inoculated, and the virus concentration in each plant was determined by indirect ELISA. The quantitative and qualitative analyses were carried out. The first one, based on the virus concentration of each plant, suggest oligogenic inheritance with heritability of 99%. The same data, when analyzed under the qualitative form, indicated an inheritance governed by two genes, with dominant and recessive epistatic interaction. However, when F_2:3 generation, arising from self-fertilization of resistant F₂ plants, was analyzed, the hypothesis of two genes was rejected, while the best fitted to data was that of one gene with complete dominance among the alleles. The qualitative analysis, considering sintomatology observed, showed that the inheritance of resistance to PepYMV is determined by a recessive gene, with the absence of dominance among their alleles.