THE INFLUENCE OF THE CONSERVATION PERIOD ON THE ACTIVITY OF MYCOLOGICAL FLORA ON ZEA MAYS SEEDS FROM SUCEAVA GENEBANK'S COLLECTION.

The purposes of the study were to establish the influence of the conservation period on the activity of micromycetes placed on stored seeds and to settle the influence of the substrate type - CGA medium (potato - dextrose - agar) and blotting paper - on the development of fungal pathogens. This study consisted in a phytopathological evaluation of epiphyte and endophyte mycological flora which appeared on Zea mays seeds placed on two types of substrates (CGA medium and blotting paper). The 30 populations of corn resulted from the active collection of Suceava Genebank and conserved for different time intervals (8 and 17 years), in controlled atmosphere storages (T=+4°C; relative air humidity = 30 - 40%). Seeds studied, placed on CGA medium and blotting paper substrate, after incubation, showed a different degree of infection by fungal pathogens, depending on the type of substrate and the age of seeds. Micromycetes were evaluated by counting the infected seeds and the attack frequency was expressed as a percentage, by visual estimation of seeds surface. The conservation period influenced fungal pathogens longevity, meaning that the more it's higher, the level of infection is reduced. On CGA medium, compared with blotting paper substrate, after incubation period, was isolated a greater diversity of fungal pathogens. The experimental results of this study answered the following objectives: - identification of fungal microorganisms according to storage period of seeds; - identification of fungal genera depending on the type of substrate used; - setting of correlations between micromycetes identified evolution, seed storage periods and the type of substrate used. [ABSTRACT FROM AUTHOR]