Effect of preharvest application of protone, methionine and oleic acid as alternative materials to ethephon for enhancing berry coloration and quality of "flame seedless" table grapes

الملخص EN

In this experiment, ten-years-old "Flame Seedless" grape-vines at El- Nubaria region, Behira governorate, Egypt, were preharvest sprayed during 2016 and 2017 seasons with water only with surfactant (control), 400 mg/ L ethephon, 100 mg/ L ProTone (active ingredient of Abscisic acid 10%), 100 mg / L methionine, 400 mg/ L oleic acid, ProTone plus methionine, ProTone plus oleic acid and ProTone plus methionine and oleic acid, in order to investigate their influence on berry coloration, berry quality of grapes and the possibility of using these materials as alternatives to ethephon treatment.

The results revealed that ethephon, ProTone, methionine and oleic acid-treated grapes increased berry anthocyanin contents, TSS and decreased berry acidity and chlorophylls.

On the other hand, the formulation containing ProTone, methionine and oleic acid possessed higher anthocyanin contents and reduced berry shattering in addition to weight loss percentage as compared with ethephon and control treatments.

This study recommended using the formulation containing ProTone plus methionine and oleic acid at véraison (10- 15% berry coloration) as an alternative to ethephon treatment for enhancing berry coloration, berry quality and overcome some adverse effects of ethephon such as increased berry shattering and berry weight loss, which reflects on berry appearance.