Evaluation of resistance to Fusarium oxysporum in genotypes of lulo (Solanum quitoense Lam.)

Abstract

Lulo (Solanum quitoense Lam.) is a fruit tree of Andean origin of national economic importance in Colombia, which constitutes an important source of employment for farmers and their families. Vascular and root wilt caused by the fungus Fusarium oxysporum is one of the most limiting diseases in the production of this species, causing low yields and considerable economic losses. As an effective control alternative for this pathogen, the identification of genotypes with resistance that can be used in breeding programs is being considered. The objective of this work was to evaluate the response of 22 lulo genotypes to the artificial inoculation of Fusarium oxysporum to identify possible sources of pathogen tolerance. F. oxysporum was inoculated on 22 genotypes of lulo plants following the method of wounded roots through artificial cutting. Distilled water inoculation and “La Selva” resistant lulo hybrid was used as control. The traits evaluated correspond to plant height, stem diameter, days to the onset of symptoms, incidence and severity. The fungus isolation was highly aggressive in S. quitoense and S. hirtum, with 96 and 84% severities, respectively. Five resistant genotypes were identified, namely 15C, 36B, HSF1, HSF10, and HSF36, which presented incidences and severities of 0% and can be considered for multi-environmental evaluation tests to determine their productive potential or they can be considered as parents for breeding programs of the species. Other genotypes, such as 15B and HSF15, showed average severities of 28 and 20%, respectively; however, thesetwo genotypes survived throughout the experiment, suggesting tolerance to the pathogen.