Abstract

Relative humidity (RH) during storage plays an important role on germination and seed vigor of Sangyod Phatthalung geographical indication—GI—rice (Oryza sativa L. var Indica cv. Sangyod-Phatthalung). This experiment aimed to evaluate germination and seed vigour of seeds of Sangyod Phatthalung under storage at different relative humidities. Rice seeds were stored in the closed system controlled relative humidity at 38%RH and 61%RH. The relative humidity was controlled using glycerol solution. The experiment was performed in completely randomized designs with 4 replicas and seed stored at 84%RH was used as a control. Seeds were drawn at 0, 1, 7 days and 3 months after storage for testing namely; direct and indirect seed moisture content, germination and seed vigour using the radicle emergence test. The results showed that germination and seed vigour decreased inversely following longer storage periods. At 3 months storage, germination and seed vigour were halved when compared to the beginning both in storage at 38%RH and 61%RH (p<0.05), while the control would lose all germination. Sangyod Phatthalung rice seeds took more than 1 week to reach equilibrium seed moisture content. The equilibrium moisture content of seeds stored in 38%RH, 61%RH and 84%RH were 4.7%, 11.1% and 13.9%, respectively.