The history of interconnected evolution of Orobanche cumana Wallr. and sunflower in the Russian federation and Kazakhstan

Abstract

Currently, Orobanche cumana in the Russian Federation overcomes the influence of dominant genes of resistance in sunflower Or4, Or5, Or6, Or7, already known in European countries, and the combined impact of the two recessive genes or6or7. The most virulent biotypes of parasite G and H are found in many regions of sunflower cultivation: the Rostov, Voronezh, Volgograd, Saratov, Orenburg, Stavropol and Krasnodar regions. The situation is especially unfavorable in the Rostov region where the race G became predominant in many populations of O. cumana. In the Krasnodar region broomrape began to spread in recent years (after a long absence) mainly in the northern regions (and adjacent), bordering with the Rostov region. Here the populations of O. cumana are a mixture of races of different virulence. The races D and E still often dominate. However, there are already the parasite populations, where the race G is predominant, and somewhere biotype H is already present. In a sample of seeds from Kazakhstan is dominating the low virulent race C, among which there is a small admixture of biotype G. This combination of low virulent race with a small amount of highly virulent specimens of biotype G indicates the natural origin of the latter, regardless of the influence of the breeding process of sunflower. Some deviations from the basic model of development of O. cumana in ontogenesis that contribute to increase and acceleration of seed preproduction of parasite's specimens are described.