Viability of seed-borne fungi Alternaria alternata, Bipolaris sorokiniana and Drechslera teres in barley seeds in the south of Brazil

Abstract

Some seed-borne fungi can survive in barley seeds; nevertheless, their survival period is unknown in barley seeds under storage conditions in Brazil. The aim of this study was to quantify the viability of the fungi Alternaria alternata, Bipolaris sorokiniana and Drechslera teres in barley seeds stored for 315 days during the off-season in the south region of Brazil. Each cultivar had 400 seeds disinfested and subjected to seed health testing in potato-dextrose-agar (PDA) from December 2011 to September 2012 at 35-day intervals. Data on fungal incidence and viability as a function of the storage time underwent regression analysis. All three fungi were detected in the five cultivars in all evaluated periods, and their incidence and viability significantly reduced with increasing storage periods. Monthly average reduction in the viability of A. alternata was 8%, while that of B. sorokiniana and D. teres was 10%. At the end of the off-season, viability of A. alternata, B. sorokiniana and D. teres, considering the average of cultivars, remained 49.8, 29.6 and 31.0%, respectively.

Net blotch (Pyrenophora teres Drechsler): An increasingly significant threat to barley production

“…Based on these symptoms, the author classified the pathogens into two forms: P. teres f. teres (or the net form), which causes net-like symptoms (Figure 1A and 1B), and P. teres f. maculata (or the spot form), which causes symptoms in the form of dark spots (Figure 1C and 1D). Lightfoot and Able (2010) similarly noted that the different pathogen forms have distinct pathophysi- (Shipton et al 1973;Brown et al 1993;Toth et al 2008;Mikhailova et al 2010;Ficsor et al 2010Ficsor et al , 2014El-More 2016;Poudel 2018;Ronen et al 2019;Agostinetto et al 2020;Garozi et al 2020;Uranga et al 2020) https://doi.org/10.17221/122/2023-PPS ologies (resulting in different lesion symptoms). According to these authors, net-form symptoms initially appear as small spots or streaks, which later enlarge, elongate and form narrow, darkbrown, necrotic longitudinal bands resembling a net-like pattern.…”

“…spontaneum and H. murinum ssp. glaucum), which are considered to be the main hosts of net blotch forms alongside cultivated barley (Shipton et al 1973;Ficsor et al 2010Ficsor et al , 2014Ronen et al 2019;Agostinetto et al 2020).…”