Three varieties of rice seed (Oryza sativa L.) BR-IRGA 410 and BR-IRGA 414 (semi-dwarf type) and Bluehelle (intermediate type) were treated with plant growth regulator (PRO-GIBB), thus active ingredient is Gibbcrellic Acid (GA3) on six doses: 0,0; 0,25; 0,50; 0,75; 1,00 and 1,25g GA3/50kg of seeds and seeds and in four depth: 2, 4, 6 and 8cm at two periods; april, under low temperature and october, the recomended period. The follow parameters were evaluated: field emergence, speed of emergence index, dry matter eight and seedling height. The results allowed to conclude what the GA3: a) increase field emergence, speed of emergence index and seedling height; b) increase dry matter weight in semi-dwarf variety in seeded with low temperatures; e) the dose more adequade were 1,00g GA3/50kg seeds for DR-IRGA 410 and BR-IRGA 414 variety and 0,75g GA3/50kg seeds for Bluebelle variety.