Evaluation of Host Resistance to Botrytis Bunch Rot in Vitis spp. and Its Correlation with Botrytis Leaf Spot

Abstract

Abstract. Botrytis cinerea, the causal agent of Botrytis bunch rot and gray mold, is the number one postharvest disease of fresh grapes in the United States. Fungicide applications are used to manage the disease, but fungicide-resistant isolates are common and postharvest losses occur annually. Host resistance is needed for long-term management of the disease. Sources of resistance in grape have been identified, but often have poor fruit quality. In this study, 27 grape lines (cultigens and species), including high fruit-quality Vitis vinifera, were evaluated for fruit and leaf susceptibility to two isolates of B. cinerea. No significant differences in virulence or pathogenicity were detected between the two isolates, but differences in disease incidence were evident among lines in leaves and berries. Most V. vinifera cultivars evaluated had high disease incidence in berries, whereas complex hybrids, Vitis aestivalus and Vitis arizonica, had low-to moderate disease incidence. Two V. vinifera breeding lines had moderate susceptibility (<50% disease) to Botrytis bunch rot when inoculated with either isolate. Only one V. vinifera line had little (<5%) to no berry or leaf disease when inoculated with either isolate. Moderate resistance (10% to 25%) was detected in Vitis spp., and a single V. vinifera line. Correlations were examined among soluble solids, leaf susceptibility, and fruit susceptibility. No correlations between soluble solids and disease susceptibility (leaves or berries) were identified, but moderate correlations between leaf and berry susceptibility were observed. Moderate resistance to Botrytis bunch rot and leaf spot were detected in Vitis breeding lines, suggesting these may be useful for developing grape cultivars with high fruit quality and resistance to B. cinerea.

Scion Breeding for Resistance to Biotic Stresses

“…Little or no resistance exists in berries of V. vinifera cultivars, whereas North American grape species or hybrids such as M. rotundifolia, V. labrusca or V. labrusca  V. vinifera hybrids were found to be highly resistant. Similar results were obtained by Naegele (2018). Highly resistant cultivars were characterized by a number of properties including (a) a low number of surface pores on berries, (b) a thick cuticle and a high wax content and (c) the number and thickness of epidermal and hypodermal cell layers.…”

“…Little or no resistance was observed with V. vinifera cultivars, whereas eighteen of the thirty Chinese Vitis species were resistant to the fungus with the highest levels of resistance observed with selected accessions of V. amurensis, V. adstricta and V. yenshanensis. However, how leaf resistance relates to berry resistance in these genotypes requires further examination, especially as the two V. labrusca  V. vinifera hybrids tested were found to be highly susceptible to B. cinerea, which would appear to be at odds with the results of other B. cinerea assays using individual berries (Gabler et al 2003;Naegele 2018).…”

The Destructive Fungal Pathogen Botrytis cinerea—Insights from Genes Studied with Mutant Analysis

“…(grapevine species). However, these resistant cultivars carry undesirable commercial traits such as thicker skins and increased epidermal waxes [28]. Similar to other necrotrophic pathogens, resistance against B. cinerea is mostly multigenic.…”

“…Similar to other necrotrophic pathogens, resistance against B. cinerea is mostly multigenic. In addition, fungal pathogen resistance genes appear to be negatively correlated with fungicide resistance genes, hindering efficient breeding [28].…”

Potential Fertilization Capacity of Two Grapevine Varieties: Effects on Agricultural Production in Designation of Origin Areas in the Northwestern Iberian Peninsula

“…The epidemiological characteristics of the fungi responsible for these pathologies depend, among other factors, on the airborne spore concentrations [11]. Therefore, to know the host resistance is useful for the long-term management of the disease [12,13]. Many works on grapevine phytopathology have been developed during the last years, providing valuable information for crop protection in order to ensure a successful vintage [14][15][16].…”