Comparison of defence responses of detached leaves of local strawberry cultivars against grey mould disease

Botrytis cinerea, one of the most critical diseases in strawberry cultivation, significantly reduces strawberry production worldwide. One of the standard practices for B. cinerea management is chemical fungicides. However, the effects of these fungicides have decreased in time due to fungal resistance. Besides, these fungicides have become increasingly unacceptable because of both public concerns and environmental pollution. So, it is prominent to search for environmentally-friendly control agents to fight against Botrytis cinerea. Phenolic compounds are well known to play a significant role in plant defence mechanisms against plenty of insect pests and plant pathogens. For this purpose, in this study, we determined the effects of grey mould disease on free radical scavenging ability (DPPH), the total phenolic compound, and phenolic contents of detached leaves of different strawberry cultivars. Grey mould resulted in a decrease in free radical scavenging ability (DPPH%) and total phenol content in all strawberry cultivars apart from the ‘Kara’ cultivar. ‘Kara’ had the highest DPPH content (84%) and the entire phenol content (1475 mg GAE 100 g^‑1). We also identified the gallic acid, ellagic acid, caffeic acid, p-coumaric acid, myricetin, quercetin, kaempferol in the detached strawberry leaves quantified by HPLC techniques. Grey mould decreased in some of the strawberry leaves’ phenolic content, while it increased in some of the strawberry leaves’ phenolic content. According to the obtained results, ‘Kara’ was more tolerant against Botrytis cinerea than ‘Osmanlı’ and ‘Tüylü’.