Published in Scientific Papers. Series A. Agronomy, Vol. LVIII
Written by Lavinia-Mariana BERCA
Alternaria species have a variable affinity for host although they are often found in conjunction. The aim of this studywas to compare the distribution of six Alternaria species present in infected seeds samples taken directly from twodistricts in South Romania. Ten samples of seeds were taken directly from ten different growing fields in Teleorman andCalarasi, in June, just prior to harvest. For each of the ten samples has been performed three replicates, each of fiveseeds. Overall 150 seeds were placed on Petri dishes (ø 10 cm) on PDA. A semi-permanent slides was performed fromeach of the colonies formed around the seeds after 10 days of incubation, at 21ºC. These slides were analyzed, field byfield, under a microscope (x40), until 50 conidia of Alternaria species were identified. For each replicate an average of2350 conidia (150-250 conidia/ plate) were identified with certainty on 94% in vitro colonies formed by pathogensaround the seeds. Alternaria brassicicola was the most frequent species identified on seeds from growing fields inCalarasi (53.91%) and Teleorman (57.12%). We found that A. brassicicola and A. brassicae were present on allinfected seeds whereas A. brassicicola, A. brassicae and A. radicina were detected on 93.62% colonies formed aroundthe seeds. The relative distribution of A. brassicae (p < 0.0001), A. brassicicola (p < 0.0001), A. radicina (p = 0.001)and A. solani (p = 0.0003) in samples from Calarasi and A. radicina (p = 0.004), A. solani (p = 0.028), A. tenuis (p =0.0006) in samples from Teleorman were found be present statistical significant differences. Overall these resultsindicated that the distribution of Alternaria species can present significant variations even if samples from the samedistrict are investigated.
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Alternaria
