Daniela Valkova and Valentina Encheva
Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria
Valkova, D. & Encheva, V. (2021). Wild annual Helianthus species as sources for resistance to some foliar pathogens on sunflower. Bulg. J. Agric. Sci., 27 (5), 942–947
Phytopathological investigations of hybrid progenies, originated from wild annual Helianthus annuus L. and Helianthus argophyllus Torr. & Gray, were carried out. Cultivated sunflower was represented by five male sterile lines, developed in DAI, General Toshevo. Presence of resistance to grey (Phomopsis helianthi), brown (Alternaria sp.) and black (Phoma macdonaldi) spots on sunflower was established for hybrid plants in F2 generation. The hybrid material was grouped according to the type of infection and its reaction to the different pathogens. Four groups of hybrid crosses were selected – the first group included materials, resistant to all three pathogens, the second group included materials, resistant to pathogens caused grey and black spots, the third – resistant to pathogens caused black and brown spots, and the fourth – resistant to pathogens caused grey and brown spots on sunflower. The seed oil content and the vegetation period were determined for all studied hybrid forms. The obtained resistant hybrid forms with proved transfer of Rf genes and increased seed oil content will be an important initial material in sunflower breeding program in DAI for developing new R lines.