Resistance of hybrid wine grape breeding forms to downy mildew (Plasmopara viticola Berkeley et Curtis)

Iliana Ivanova, Ralitsa Mincheva, Galina Dyakova and Gergana Ivanova-Kovacheva

Abstract: In the period 2014-2016, at the experimental vineyard of the Institute of Agriculture and Seed Science “Obraztsov Chiflik” – Rousse, the resistance of hybrid wine grape breeding forms to downy mildew with causative agent Plasmopara viticola (Berkeley et Curtis) oomycetes fungus was studied. Objects of the study were the hybrids: 25/12 (Pamid Rousse 1 × Kaylashki Misket), 5/51 (Naslada × Chardonnay) and 5/83 (Naslada x Chardonnay). Misket Otonel cultivar was chosen as control. The aim was the reaction of hybrid wine breeding forms of vine to downy mildew caused by Plasmopara viticola (Berkeley et Curtis) to be determined. The phytopathological assessment of the attack of Plasmopara viticola on leaves was carried out according to the OIV 452 scale, and on berries and clusters – according to the OIV 453 scale, where the resistance was represented in 5 grades 1-3-5-7-9, as 1 was maximum resistance. The following traits were registered: index of attack (%), correlation coefficient between disease progression and yield obtained, weight of cluster (kg), maturation period, sugar content (%), acid content (g/l). Hybrid 25/12 (Pamid Rousse 1 × Kaylashki Misket) showed maximum resistance, while 5/51 (Naslada × Chardonnay) and 5/83 (Naslada × Chardonnay) were moderately resistant.

Keywords: downy mildew; Plasmopara viticola; resistance; wine grapes

Date published: 2020-04-30