Osmotic and heat treatments on control of fungi associated with seeds of Eugenia brasiliensis and E. pyriformis (Myrtaceae)

Abstract

Abstract: Desiccation sensitive seeds, such as those of Eugenia brasiliensis Lam. (grumixama) and E. pyriformis Cambess. (uvaia), also known as recalcitrant, need to be stored with high water content and temperatures above 0 °C. Such conditions keep these seeds with high metabolism, thus reducing their longevity, and allowing the development of microorganisms, especially fungi, accelerating their deterioration speed. Heat and osmotic treatments have shown some success for the control of some fungi associated with these seeds. However, to better measure the effectiveness of these treatments, the evaluation criteria needs to be refined, taking into account not only their incidence but also their intensity. Thus, in the present study, the percentage of seeds infected by the fungi (incidence) as well as the degree of infection on the seed surface (severity) of E. brasiliensis and E. pyriformis were evaluated after applying heat and osmotic treatments which controlled most fungi found in these seeds, except for Fusarium sp. and Penicillium sp. The evaluation of the severity showed that the effect of the treatments is not only quantitative, reducing the number of infected seeds; there was also a change in the development of the fungi, often reducing the severity of the infection, thus enabling the detection of differences between treatments that were not easily recognized when only using the incidence evaluation.