Rice seed germination attributes dried by a recirculating dryer

ABSTRACT Using quality seed is a forcible factor in stabilizing agricultural crop production. Rough rice usually has moisture contents over 20 percent during harvest time. Grain respiration and transpiration cause seed deterioration and make it vulnerable to microorganisms, insects, and other pests. Hence, grain moisture content has to be kept at a certain level to maintain seed quality. An appropriate drying air temperature should dry Rough rice to a desired final moisture content. In this study, newly harvested paddy (Hashemi cultivar) was dried by a recirculating dryer with three drying air temperatures (37, 42, and 48 °C) until two final moisture contents (12 and 14% w.b.). The effect of parameters was examined on seed germination characteristics (i.e., germinability, mean ger mination rate, germination energy, and seedling vigor index). The results revealed that drying air temperature and the final seed moisture content affected germinability and seedling weight vigor index significantly (p < 0.01). Seedling length vigor index and germination energy were only influenced by drying air temperature (p < 0.01). The highest seed germinability (80% averagely) was acquired when the seed dried by drying air temperature of 37 °C to the final moisture content of 14%. The mean germination rate was not affected by those factors. The maximum seedling length vigor index (16262) observed while drying air temperature was 37 °C . The highest seedling weight vigor index (8.186) was obtained when the seed was dried by an air temperature of 37 °C up to 14% final moisture content. The maximum germination energy (68.7%) belonged to samples treated by drying air temperature of 37 °C up to 14% final moisture content. Altogether, optimum seed drying is achieved in the drying air temperature of 37 °C up to 14% final moisture content.