Study on the cause damping-off in quinoa (Chenopodium quinoa willd.) and a method for suppressing its occurrence:

Abstract

Damping-off is one of the most threatening factor for quinoa growth and yield. In this study, to clarify the cause of the occurrence and to find a method to suppress of damping-off in quinoa (Chenopodium quinoa Willd.), we carried out field experiments in the experimental field at Nihon University from 2014 to 2017. The damping-off ratio remarkably varied with the sowing time. Damping-off occurred from the emergence stage to fourth leaf stage at all sowing times, but, not after the fourth leaf stage. The reason for the difference in damping-off ratio with the sowing time was not the difference in temperature or sunshine hours but the difference in precipitation. The damping-off ratio was also decreased under a lower soil moisture condition. Thus, one method to suppress damping-off was to decrease the soil moisture at an early growth stage. There were no significant differences in the damping-off ratio among 12 cultivars. Rhizoctonia spp. and Fusarium spp. were observed from the seedlings with damping-off symptoms. We considered that those fungi caused damping-off in quinoa seedlings. Damping-off was suppressed by the broadcasting of more than 2g per m2 of Dakoreto wettable powder to the soil surface. From this study, we identified a cause of damping-off in quinoa and suggested a method to suppress damping-off in quinoa.