Seedling growth of irrigated rice as a function of seed treatment with gibberellic acid

Resumo

This study aimed to evaluate the early growth stages of irrigated Oryza sativa L. (rice) seedlings from cultivars SCS-112, BRS-7 Taim, BR IRGA 410 and IRGA 417, under three different temperatures, i.e. 15, 20 and 25 ºC, as a result of seed inbibition in a gibberellic acid (GA₃) solution at concentrations of 0, 150, 300, 450, 600 and 750 mg L^-1. The lengths of the shoot and the primary root of seedlings were recorded at three, 7 and 21 days from sowings on germination paper. Interactions between the main factors were observed for all the response variables. Cultivar BRS-7 Taim shows a better response three days after sowing to inbibition of seeds in GA₃ solution on shoot and primary root lengths. The response to GA₃ in shoot growth of rice seedlings increases as the temperature is raised, which also increase the concentrations of greater growth increment due to the regulator. Root growth is little affected by the GA₃ at 7 and 21 days after sowing. Rice cultivars have different sensibility to exogenous gibberellin concentrations via seed treatment, reflecting upon seedling performance.