| dc.description.abstract | Vine decline disease (VDD) caused by the fungus Monosporascus cannonballus, is a major threat to melons (Cucumis melo L.) production worldwide. Resistance has been identified in some melon accessions, yet little is known abouts its genetic control and mode of action. Thus, the goals of this project were to determine the mode of inheritance and the type of gene action of the resistance found in the USDA accession: PI 124104 as well as to identify metabolites involved in it. The F1, F2, BC1 and BC2 populations from the cross of VDD-susceptible parent, TAM-Uvalde with a resistant VDD-USDA PI 124104. Generation means analysis indicated that additive and dominant effects were present in the inheritance of the VDD resistance trait. Broad-sense heritability estimate of this trait was high (0.74) and narrow-sense heritability estimate was moderate (0.47). Chi-square analysis indicates that the resistance is controlled by three independent genes. Additionally, mid parent-offspring regression showed that some hybrids developed with the variety USDA PI 124104 exhibited medium to high narrow sense heritability values (0.6 and 0.66). However, these results may be inflated due to the presence of heterosis. Several metabolites were differentially accumulated in resistant and susceptible genotypes in response to pathogen infection. Particularly, results shows that phthalic acid is constitutive and induced in VDD-resistant genotype in response to pathogen infection suggesting a putative role on VDD-resistance reaction. However, further research using forward, and reverse genetic approaches are needed to determine the role of phthalic acid in the resistance to Monosporascus cannonballus, in melons. | |
