Development of sunflower genotypes resistant to downy mildew

Abstract

Sunflower is attacked by more than 40 different diseases of which only a certain number causes serious reduction of seed yield. One of the most damaging diseases is downy mildew, which is caused by the fungus Plasmopara halstedii (Farl.) Berl. et de Toni (syn. Plasmopara helianthi Novot.). Sunflower downy mildew has great economic importance in all countries where sunflower is grown. When the meteorological conditions during the vegetation period of sunflower become favourable for disease development, the damages produce considerable reducing of the seed yield and the oil content. The best way of controlling the fungus is to grow resistant cultivars and because of that the major objective of this study was to develop sunflower genotypes genetically resistant to dominant races of downy mildew in Serbia. During this work two co-dominant CAPS markers for Pl6 gene were developed which can also be used for Pl7 gene. For introduction of these genes in breeding program marker assisted selection (MAS) was used. Developed commercial sunflower inbred lines exhibit resistance to all known races of downy mildew in Serbia indicated incorporation of resistance to downy mildew in well-known and widely produced hybrids. Besides that, Pl-genes were introduced to a large number of new inbred lines and new downy mildew resistant hybrids. These new hybrids reach higher seed and oil yields then hybrids widely produced.