Pre-drying periods and temperatures to overcome dormancy of rice seeds of the cultivar IRGA 431 CL

Abstract:

Rice seeds have a dormancy which is understood as resistance to pre- and post-harvest germination. Thus, the present study aims to evaluate periods and temperatures in the pre-drying of rice seeds (cultivar IRGA 431 CL) to overcome dormancy. An experiment was carried out in a completely randomized design at the Didactic and Seed Research Laboratory, at the Federal University of Santa Maria. Three lots of the cultivar IRGA 431 CL were used. For the present study, temperatures of 35, 40, 45, 50 and 55 °C in a forced-air circulation oven were used to overcome seed dormancy. At each temperature the seeds remained for periods of 24, 48, 72, 96, 120, 144 and 168 h. First count, germination, and seedling root and shoot lengths were evaluated in the experiment. The data obtained were subjected to analysis of variance and compared by response surface. Temperature between 41 and 44 °C for a period of 95 h is more indicated to overcome dormancy in seeds of the IRGA 431 CL cultivar in a forced-air circulation oven.

Index terms:
exposure time; high temperatures; Oryza sativa L.