The causative agent of downy mildew Peronospora brassicae Gaeum. f. brassicae (Gaeum.) on winter false flax (Camelina sativa (L.) Crantz.): the search for a source of disease resistance in the conditions of the Krasnodar region

V.S. Pustovoit All-Russian Research Institute of Oil Crops, Krasnodar, 350038, Russia

^* Corresponding author: oserduk@mail.ru

Abstract

In recent years, in the conditions of the central zone of the Krasnodar region, downy mildew has become the most dangerous disease of winter false flax that affects the crop yield. Either the infected plants do not develop reproductive organs or these organs are undeveloped. The development of varieties resistant to infection by the disease causative agent allows efficient reducing the seed yield loss of winter false flax due to downy mildew without the use of chemical products. In 2015-2019, we conducted an assessment of the breeding material (528 cultivar samples) of winter false flax for resistance to downy mildew affection on a natural infection background. We determined that the causative agent of the disease is Peronospora brassicae Gaeum. f. brassicae (Gaeum.) Dzhan. We divided all cultivar samples into groups according to their resistance to the disease: immune, resistant, weakly resistant, weakly susceptible, susceptible. As a result of research, we selected 5 breeding samples (## 724, 726, 728, 730, 738) that were immune to downy mildew in the course of several years, with yield exceeding the standard variety Karat by 0.22-0.38 t/ha, and with oil content exceeding the standard by 0.2-0.5 %. We proposed to use the selected cultivar samples in the breeding process with the aim of developing new false flax varieties resistant to downy mildew.