Sunflower (Helianthus annuus L.) breeding for durable resistance to Downy mildew (Plasmopara halstedii)

Abstract Downy mildew is one of the most important diseases of sunflower crop around the world caused by Plasmopara halstedii (Farl.) Berl.et de Toni. The aim of our study is the sunflower hybrid development with the durable resistance to downy mildew, combining one parental line with the most effective for the specific location major gene (Pl 15 for example) and the second parental line – with a high horizontal resistance to downy mildew. Experiments were conducted at All-Russia Research Institute of Oil Crops in 2016–2021. Experimental design was randomized blocks with three replications. CMS-lines with the highest level of horizontal resistance (VK 678, VA 732, VK 680, VK 934, VK 900 and new line SL 0516) were used as mother parents. Lines with Pl 15, resistant to all the downy mildew races were used as pollinators to create sunflower hybrids with durable resistance to downy mildew. A number of high-productive sunflower hybrids with durable resistance to DM (VK 732А × L 642-15, VK 732А × L 634-15, VK 680А × L 642-15, VK 680А × L 634-15, VK 934А × L 642-15 and VK 678А × L 634-15) were developed and tested.