Achievements in sunflower breeding for resistance to diseases, broomrape and insects

Abstract

The original genetic base of the cultivated sunflower is very narrow and deficient in genes for resistance to causal agents of diseases, broomrape, insects, and other stress factors. The existence of the wild relatives of the cultivated sunflower, i.e. the wild species of the genus Helianthus, makes it possible to overcome a significant number of problems caused by the narrow genetic base of the cultivated form of this plant. Sunflower breeders have managed to discover in the wild species genes for resistance to a number of pathogens and they have incorporated them into cultivated sunflower genotypes by interspecific hybridization. Still, the frequent appearance of new races of downy mildew, rust and broomrape requires the breeders to remain constantly active in finding and incorporating new resistance genes into this crop. Successful breeding efforts have resulted in the incorporation of genes for resistance to Plasmopara halstedii, Puccinia helianthi, Verticillium wilt, Erysiphe cichoracearum and Orobanche cumana into cultivated sunflower genotypes from the wild Helianthus species. High tolerance towards Phomopsis, Macrophomina, Albugo and Alternaria has been incorporated as well. High degrees of tolerance to Sclerotinia and Phoma have also been attained. The use of new biotechnology methods, especially the molecular marker techniques, speeds up the process of discovering new resistance sources. This becomes very important with diseases whose inheritance is polygenic in character. Sunflower breeding for resistance to insects has thus far produced more modest results, with the exception of the sunflower moth, resistance to which has been discovered in the wild species and incorporated into the cultivated sunflower.

Izvorna genetska osnova gajenog suncokreta je veoma uska i deficitarna u genima za otpornost prema prouzrokovačima bolesti, volovodu, insektima i drugim stresnim faktorima. Postojanje bliskih srodnika (divljih vrsta) u rodu Helianthus omogućava prevazilaženje većeg broja problema. Oplemenjivači suncokreta su uspeli da otkriju gene za otpornost prema više patogena u divljim vrstama i da ih ugrade, putem interspecies hibridizacije, u genotipove gajenog suncokreta. Međutim, brza pojava novih rasa kod plamenjače, rđe i volovoda zahteva od oplemenjivača stalnu aktivnost u pronalaženju i ugradnji novih gena. Uspešnim oplemenjivačkim zahvatima, iz divljih vrsta preneti su geni u genotipove gajenog suncokreta za otpornost prema Plasmopara halstedii, Puccinia helianthi, Verticillium wilt, Erysiphe cichoracearum i Orobanche cumana. Takođe, ugrađena je i visoka tolerantnost prema patogenima iz rodova Phomopsis, Macrophomina, Albugo i Alternaria. Pored toga, ostvarena je zavidna tolerantnost prema Sclerotinia i Phoma. Korišćenje novih metoda biotehnologije, a pre svega primena tehnika molekularnih markera, ubrzava pronalaženje novih izvora otpornosti. Ovo je veoma bitno kod bolesti gde je nasleđivanje poligenog karaktera. Oplemenjivanje suncokreta na otpornost prema insektima u dosadašnjem periodu je dalo skromnije rezultate, sa izuzetkom suncokretovog moljca, gde su pronađeni geni otpornosti i ugrađeni u genotipove gajenog suncokreta.