Pyrenophom tritici-repentis: A cause of pseudo-resistance to Puccinia triticina

Abstract

Fourteen winter wheat varieties obtained from the Czech Republic for testing disease resistance were sown in dishes and grown in the field next to the LRTCW line and variety Rodna of Serbia and Montenegro, 2003. All genotypes were found by the type of reaction to be susceptible to Puccinia triticina at the seedling stage in the greenhouse. In four varieties with comparatively short leaves, Pyrenophora tritici-repentis was found to appear at a frequency of 20% on the leaves below the last two. The following year untreated seeds of all varieties were sown in the field and no Pyrenophora tritici-repentis was found. The average difference in the intensity of Puccinia triticina infection on the last two leaves between the two years was 51% for the varieties with P. tritici-repentis, and 23% for the other group. Even small amounts of toxins decreased the development of the obligate parasite. The hypothesis of a seed-borne character of Pyrenophora tritici-repentis was supported in the other varieties grown in close proximity. They showed early spike maturation, compared with the flag leaf and lower resistance to low temperatures in 2004 and 2005.

Četrnaest genotipova ozime pšenice dobijenih iz Češke Republike radi testiranja na otpornost prema prouzrokovačima bolesti, posejano je (2003. godine) u saksije i uzgajano u poljskim uslovima pored LRTCW linije i sorte Rodna iz Srbije i Crne Gore. Po tipovima reakcije svi genotipovi su bili osetljivi prema Puccinia triticina u stadijumu sejanaca u stakleniku. Na sortama sa relativno kraćim trajanjem lisne površine Pyrenophora tritid-repentis je pokrila 20% lisne površine ispod poslednja dva. Sledeće godine seme pomenutih genotipova je posejano u polju, ali nije došlo do pojave žuto-mrke pegavosti. Prosečna razlika po intenzitetu zaraze sa R triticina između dve godine je na sortama sa R tritici-repentis bila 51% a za ostale 23%. Utvrđeno je da su čak i manje doze toksina smanjile razvoj obligatnog patogena R triticina. Hipoteza o prenošenju prouzrokovača žuto-mrke pegavosti semenom podržana je i preko drugih sorti gajenih u blizini. One su ispoljile rano odumiranje klasa u odnosu na zastavičar (u našim uslovima) i slabiju otpornost prema niskim temperaturama u 2005. godini.