engleski

Estimation of quantitative genetic parameters for fusarium head blight resistance in winter wheat

Each year Bc Institute d.d. performs screening of its most improved winter wheat breeding lines for Fusarium head blight (FHB). The 18 best breeding lines are planted in field trials (RCBD, four replications) together with five standard winter wheat cultivars (Lucija, Pon- cheau, Renan, Roazon and Žitarka) and three FHB infection methods (spray method, deployment of Fusarium infected corn stalks and natural infection) are applied. Disease severity ratings are scored as visual rating index (VRI) and % of Fusarium damaged kernels (FDK). In the present study, results obtained for five standard cultivars during four experimental years (from 2011 to 2014) are presented. Cultivars and years were modelled using the PROC GLM in SAS/STAT (SAS Institute Inc. 2003). Components of variance were estimated using the PROC VARCOMP. Genetic correlations (rG), calculated as proposed in Falconer and MacKey (1996), as well as Pearson’s correlation coefficients (rP), computed using PROC CORR, were calculated over four years between the methods of infection and two disease ratings. Also, for both disease ratings and each method of infection broad sense heritability (h2) for disease resistance was calculated according to Hallauer et al. (2010). Among the cultivars significant differences for FHB resistance were found for all methods of infection and both disease ratings except for FDK under conditions of natural infection. The highest FHB severity scored both as VRI and FDK was observed using the spray method of infection. Deployment of FHB infected corn stalks, what simulated the narrow crop rotation production practice where winter wheat is planted after maize, generally resulted in lower FHB scores than spray method, but it does not require the production of inoculum and could be applied even in situations where breeding nursery is not near the laboratory. The Pearson’s correlation coefficients among the methods of infection and disease ratings were all positive, and the strongest was determined between VRI scored using the spray method of infection and VRI using the deployment of corn infected stalks (r= 0.84**). The highest h2 for both disease ratings (0.84 for VRI and 0.78 for FDK) was observed using the spray method of infection, while the smallest (0.24 for both VRI and FDK) was observed under conditions of natural infection, confirming the necessity for performing artificial infection in FHB selection trials.

fusarium ; correlation ; winter wheat

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