Cold-hardening of winter triticale (x Triticosecale Wittm.) results in increased resistance to pink snow mould Microdochium nivale (Fr., Samuels & Hallett) and genotype-dependent chlorophyll fluorescence modulations

Abstract

The resistance of triticale (x Triticosecale Wittm.) to infection of snow mould Microdochium nivale (Fr., Samuels & Hallett) was examined under different temperature pre-treatment regimes. The results of laboratory “cold chamber” resistance tests correlated with the breeders’ report from field experiments. Studied genotypes differed substantially in their resistance to infection. Two cultivars: ‘Magnat’ (susceptible) and ‘Hewo’ (relatively resistant) were further studied as a plant model to test the role of pre-hardening and cold-hardening induction of resistance expression. Both model cultivars were susceptible to M. nivale infection without cold pre-treatment and gained genotype-depended level of resistance after 4 weeks treatment at 4°C, moreover the resistance grew gradually. Simultaneously to the resistance tests, the measurements of chlorophyll fluorescence parameters were taken. The results showed that higher vitality index Rfd of cold-hardened triticale seedlings correlated with increased pink snow mould resistance while differences in other parameters of fluorescence were not distinctly significant. Establishment of Rfd in 4 weeks hardened triticale seedlings could be used for a large scale screening of breeding material in order to select potentially resistant genotypes. Such analyses have not been reported for triticale before.