DIVISION OF GENETICS AND PLANT BREEDING

34Effect of Fusarium head blight infection andfungicide treatment on mycotoxin content ingrain of spring barley cultivars (GA ČRProject 521/02/0099)Six spring barley cultivars registered in the CzechRepublic and resistance sources Chevron and CI4196 were inoculated in field trials with fourisolates of F. culmorum and F. graminearum andexamined for the content of deoxynivalenol (DON)in grain, pathogen DNA content (using quantitativereal-time PCR analysis) and yield traits. One of thefour Fusarium isolates used for inoculations was apredominant nivalenol producer while the otherisolates were deoxynivalenol (DON) producers.Among the other mycotoxins 3-AcDON was foundin grain at a relatively higher concentration.Significant cultivar differences in DON content andexamined yield traits were detected after sprayingof inoculum on two dates and mist irrigation ofinfected plots. When inoculated with an aggressiveisolate of F. culmorum, cultivars Chevron and CI4196 showed high resistance and cultivars Jersey,Olbram and Scarlett moderate resistance to DONaccumulation in grain. Treatment with fungicideHorizon 250 EW (active ingredient tebuconazole)led to a 52.5% reduction of DON content onaverage, but the effectiveness of fungicidetreatment was highly influenced by the year andcultivar. Fungicide treatment did not have anysignificant effects on grain weight per spike and, ingeneral, the effects of infection on the examinedyield traits were low in these experiments. DONcontent was closely related only with the parameterCT Fus (transformed) from quantitative real-timePCR analysis. Applying the developed PCR system itwas possible to clearly specify cultivar reactions toinfection and effects of fungicide treatment onDON content. (Šíp V., Chrpová J., Sýkorová S.,Leišová L., Kučera L., Ovesná J.)Relative concentration of Barley yellow dwarfvirus (BYDV) in Yd2 and non-Yd2 springbarley lines (GACR Project 521/03/0137)Juvenile plants of spring barley doubled haploid(DH) lines of Igri/Atlas 68 cross differing inresistance to BYDV were examined in a growthchamber for relative BYDV concentrations in rootsand plantlets. Lines were divided into tworesistance groups according to presence (Yd2+) orabsence (Yd2-) of BYDV resistance gene Yd2,which was determined with the use of PCR markerYlp. A methodical approach was elaborated forcomparison of Yd2+ and Yd2- lines by detection ofrelative BYDV content (absorbency value) by (TAS)-ELISA. The plants were inoculated with PAV isolateof BYDV at 1 – 2 leaf stage. Artificial inoculationwas carried out by placing greenhouse-rearingaphids (Rhopalosiphum padi) on the plants. Noninfectedplants were used as a negative control. Inthe first study the leaves and roots of DH lines werecollected 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42and 45 days after infection. The first symptoms ofBYDV were observed 18 days after infection insusceptible (Yd2-) and 25 days after infection inresistant lines (Yd2+). The yellowing and dwarfingof Yd2- plants were stronger than in Yd2+ plants. Inthe second study the roots were sampled 12 hoursand 1, 3, 6, 9, 14 days after infection. The collectedleaves and roots were frozen. Roots of susceptiblelines were strongly reduced whereas roots ofresistant lines had similar lengths as negativecontrols. Significant differences in absorbencyCorrespondencebetween DONcontent in thegrain of 8 springbarley cultivarsand pathogenDNA content(CT Fus from RTPCR) afterinfection withFusariumculmorum (I)and fungicidetreatment (IF)