Testing for sclerotinia resistance of different sunflower genotypes

Abstract

Resistance of F1, F2, and BC1 generations from crosses between cultivated sunflower inbreds with different tolerance towards Sclerotinia, as well as the inbred lines themselves to different forms and methods of infection with Sclerotinia in order to find out the genotypes of interest for breeding was tested. All tested genotypes showed a high level of tolerance toward artificial root inoculation with sclerotia, where three out of five tested hybrids were more resistant than their respective mother line. All tested genotypes, except for PR-ST-3A, were more susceptible to stem inoculation with sclerotia than stem infection with mycelium. All hybrids and all progeny from back crosses with the mother line were more resistant to stem infection with mycelium than parental lines, and progeny from back crosses was more resistant than or equally resistant as hybrids. In artificial inoculation of heads with mycelium and sclerotia, some tested genotypes were more susceptible to mycelium test, while others were more susceptible to sclerotia lest. There was no regularity in susceptibility of hybrids to sclerotia test regarding parental lines. All hybrids, except for Ha-48A x RUS-RF-OL-168, were significantly more susceptible to sclerotia test on stem than both parents. Hybrid Ha-48A x RUS-RF-OL-168 had the similar level of resistance as better parent.

Ispitivana je otpornost F1, F2, i BC1 generacija nastalih ukrštanjem inbred linija gajenog suncokreta različite tolerantnosti prema Sclerotinia, kao i samih inbred linija na različite forme i metode infekcije sa Sclerotinia u cilju pronalaženja genotipova interesantnih za proces oplemenjivanja. Svi ispitivani genotipovi su pokazali visok stepen tolerancije prema veštačkoj zarazi korena sklerocijama, pri čemu je tri od pet testiranih hibrida bilo otpornije od linije majke. Svi ispitivani genotipovi, osim PR-ST-3A, su bili osetljiviji na veštačko zaražavanje stabla sklerocijama u odnosu na veštačku inokulaciju micelijom. Svi hibridi kao i svo potomstvo iz povratnih ukrštanja sa linijom majke su bili otporniji na veštačku inokulaciju stabla micelijom od roditelja, s tim što je potomstvo iz tih povratnih ukrštanja bilo otpornije ili u nivou sa hibridima. Prilikom veštačke inokulacije glava micelijom i sklerocijama, pojedini ispitivani genotipovi su bili osetljiviji na metod veštačke inokulacije sa micelijom, dok su drugi bili osetljiviji na veštaču zarazu sklerocijama. Nije uočena pravilnost u osetljivosti hibrida na veštačku zarazu sklerocijama u odnosu na roditeljske komponente. Svi hibridi osim Ha-48A x RUS-RF-OL-168, su bili značajno osetljiviji na test sklerocijom na stablu od oba roditelja. Hibrid Ha-48Ax RUS-RF-OL-168 je bio u nivou boljeg roditelja.