Efeitos do ácido propiônico no desenvolvimento de plântulas mutantes de arroz

Propionic acid effects on the development of rice mutant seedlings Hydromorphic soils present as main feature a reduced natural drainage ability, being mostly used for growing irrigated rice in southern Brazil. Thus, the occurrence of anaerobic conditions associated to the presence of organic matter favors the development of anaerobic microorganisms that produce phytotoxic substances. The objective of this work was to evaluate 40 rice mutant families, obtained by mutation induction in genotype BRS 7 “Taim”, for the response to the phytotoxic action of propionic acid produced under these conditions. The experiment was performed in hydroponic culture with 4 propionic acid doses (0; 3; 6 e 9 mmol/L) arranged in a randomized block design with 3 replications. The variables root and shoot length, number of roots, root and shoot dry matter were measured. Variance analysis was performed using a factorial model, relative reduction and regression adjustment. Dose effect was not significant only for number of roots. Relative reduction for root length was the most affected by the acid and the regression established for this character showed that the mutation induction with 60 Co created variability for the character propionic acid tolerance in the genotype BRS 7 “Taim”.