Screening of wild helianthus species for resistance to high virulent Orobanche cumana Wallr., affecting sunflower in the Rostov region of the Russian Federation

Abstract

SUMMARY During the last years in Rostov region of Russian Federation highly virulent biotypes of broomrape have propagated, affecting both hybrids of foreign breeding, and the native sunflower assortment, which used to be resistant earlier. Apart from that, the resistance of some known European sunflower types to broomrape races had disappeared, which testifies about the presence of the races F, G, H in the region at least. Consequently, the search of the sources of resistance is urgent. 14 samples of annual and 27 of perennial wild sunflower from the collection of Kuban experimental station VIR were tested for resistance to the most virulent broomrape population. From the annual species only H. petiolaris had weak degree of affection (1-3 tubercles/plant), while the other were affected to a high degree. The majority of perennial sunflower samples have shown the immunity. Perennial wild species of the sunflower of the same name that were used earlier in the research of Ruso et al . (1996) as resistant species against the Spanish populations of broomrape, show resistance also to high virulent O. cumana , which had propagated in the Rostov region of the Russian Federation. The immunity to broomrape of the studied wild perennial sunflower samples is not related to the absence of stimulating effect of root exudations on the seeds of the parasite. The immunity is more likely connected to physiologicalbiochemical features of cortex root cells.