Genetic control of resistance to Liriomyza sativae by antixenosis in the melon accession

Abstract

In melon, characterizing germplasm allows identification of genotypes resistant to leafminers; knowing the genetic control of this resistance is indispensable for use in breeding. In this study, the genetic inheritance of resistance to L. sativae by antixenosis was investigated in the melon accession CNPH 94-244 (P_R) in crosses with the susceptible hybrids ‘Goldex’ (P_S) and ‘Iracema’ (P_S’), generating two populations. The plants were infested by the insect in screened plant enclosures and in the field. In the enclosures, the number of leaf mines and pupae per plant were evaluated; and in the field, a subjective score was attributed and the number of mines per leaf were counted. The genetic studies were based on the mean values and variances in the different generations (P_R, P_S or P_S’, F₁, F₂, BC₁, and BC₂), in each population. In the F₁ generation of the CNPH 94-244 × ‘Goldex’ and CNPH 94-244 × ‘Iracema’ populations, non-additive allelic interactions were observed in the genetic control of the evaluated traits. The full model explained the inheritance of the variables, with additive effects being the most significant. Narrow-sense heritability was high for mines per plant (in cages) and number of mines (in the field) in the F₂ generation of the CNPH 94-244 × ‘Goldex’ and CNPH 94-244 × ‘Iracema’ crosses, respectively. The genetic inheritance of antixenosis resistance to Liriomyza sativae in the CNPH 94-244 accession is predominantly additive, being oligogenic for subjective scores and polygenic for mines and pupae per plant in both populations. For the number of mines, inheritance was polygenic in the CNPH 94-244 × ‘Goldex’ population and oligogenic in the CNPH 94-244 × ‘Iracema’ population. Therefore, the CNPH 94-244 accession can be used as a resistant parent in breeding programs targeting leafminer resistance in melon.