Studying of inheritance of resistance in cultivated sunflower to broomrape race G (Orobanche cumana Wallr.)

Broomrape ( Orobanche cumana Wallr.) is one of the main limiting factors of sunflower production in the most countries where it is cultivated. Sunflower breeding for resistance to broomrape is one of the most effective and environmentally safe measures to protect sunflower of this parasite plant. The purpose of this research was to have an idea about inheritance of resistance to broomrape race G in sunflower line RG resistant to this race, impact of a reciprocal effect and dependence of the resistance trait from a genotype of a susceptible parental line. To study inheritance of the resistance trait, there were carried out the crosses of the line RG with susceptible sunflower lines of VNIIMK breeding: VK 551, VK 678 Б, VK 678 А, VK 1 IMI B, VK 1 IMI А, BK 301, VK 580, and reciprocal crosses only with lines VK 551, VK 678 B; VK 1 IMI B, VK 301. For the research we used methods of an artificial sunflower inoculation by broomrape and assess of plants resistance. In average 58.2% of plants in the each combination were infected, the average quantity of broomrape tubercles was 3.9 per an infected plant and 3.2 per an accounted one. The differences on traits a quantity of infected plants and an average amount of broomrape tubercles per a plant were unreliable at 5% significance level for cross-combinations of the resistant line RG with the susceptible parental lines VK 1 IMI B and VK 678 B. The differences on the trait a percentage of infected plants is reliable at 5% significance level for lines VK 551 and VK 301. The conducted researches certify the incomplete dominance of resistance trait in sunflower line RG. Both absence of reciprocal effect and dependence of resistance trait from the genotype of a susceptible parental line at some lines and their presence at some other lines are determined. The line RG can be used as a donor of resistance to the race G whereas such resistance is controlled by a dominant gene.