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Exploring the resistance of an interspecific almond × peach population to Monilinia spp.

Rosario Torres: IRTA, XaRTA-Postharvest, Edifici Fruitcentre

<div><em>Monilinia</em> spp. are responsible for brown rot, one of the most significant stone fruit diseases. Despite the efforts invested in manage and control this disease, the pathogen is not under control. Planting resistant cultivars seems to be a promising alternative but currently, most of the commercial cultivars are susceptible to brown rot. Therefore, the identification of resistant material and further analyses to uncover regions associated with brown rot resistance are necessary. The aim of this study was to conduct a Quantitative Trait Loci (QTL) analysis in an interspecific almond × peach population. Over two seasons, artificial infections with <em>M. fructicola</em> were performed in more than 100 individuals of this backcross one (BC<sub>1</sub>) population derived from a cross between the hybrid plant ‘MB 1.37’ (obtained from a cross between ‘Texas’ almond and ‘Earlygold’ peach) and the peach ‘Earlygold’ of size N=185. Fruit response to brown rot was assessed in wounded and non-wounded individuals and QTL analysis of traits related to fruit quality and to resistance to brown rot (lesion diameter and number of brown rot infected fruit) was carried out. Phenotypic data indicated differences in the response to <em>M. fructicola</em> inoculation and several non-wounded individuals exhibited resistance to brown rot. For non-wounded fruit, positive correlations were observed between resistance traits and comparisons of the same traits between seasons also resulted in significant correlations. The greater diversity among individuals led identification of locus for the presence of QTLs and could serve as a source of resistance in breeding programs.</div>