Accelerated aging test of seed vigour for predicting field emergence of wet direct-seeded rice

Abstract

Seed vigour tests enable detection of seedlots with high field emergence and storability. Here, an accelerated aging (AA) protocol is proposed as a seed vigour test for predicting field emergence of wet direct-seeded rice (Oryza sativa) seeds. Seeds of 10 rice varieties, eight with intermediate bold grain type and two with short round grain type, harvested in 2017 were subjected to AA at temperatures of 40–45°C for periods of 24–120 h, or to standard seed germination at 25°C, followed by emergence testing in a rice field. AA treatments that were found to be appropriate to predict field emergence in 2017 were repeated with the same varieties harvested in 2018. Standard seed germination could not predict field emergence of tested rice varieties (r <0.2, α = 0.01). The appropriate AA treatment to predict field emergence was dependent on the grain type. AA treatment 43°C/72 h was found to be the best for predicting field emergence of wet direct-seeded rice of intermediate bold grain type (r >0.8, α = 0.01). Further studies are needed to find the best AA test for predicting field emergence of varieties of short round grain type.