Viability and location of Microdochium albescens in irrigated rice seeds produced in pre-germinated cropping system

ABSTRACT The aims of this study were to quantify the viability of Microdochium albescens in irrigated rice seeds stored during the time between harvests and to quantify its incidence in the seed structures. Samples of irrigated rice seeds of the cultivars SCS122 Miura and SCS121 CL were monthly collected and stored during the time between harvests 2018/19. Pathology analysis and viability quantification were performed in the laboratory. The location of the fungus in the seeds was determined by separating lemma, palea, endosperm and embryo, with subsequent disinfestation and sowing in culture medium. The fungus M. albescens showed 77.8% seed storage viability for nine months, considering the average of lots and cultivars. Average incidence was 48% in the lemma, 43.7% in the palea, 24.7% in the endosperm and 20.7% in the embryo. The fungus M. albescens remains viable in rice seeds between harvests, while mycelium is detected at a higher incidence in the external tissues of caryopsis.