Butyric acid tolerance of rice mutant M4 families.

Hydromorphic soils have a low drainage capacity and are used mainly for the cultivation of irrigated rice. This condition favors the development of anaerobic microorganisms that produce phytotoxic substances. The objective of this study was to evaluate the response of rice mutants to the phytotoxicity caused by butyric acid under anaerobic conditions. The experiment consisted of four treatments arranged in a randomized block design. Plants of 40 families were grown in a hydroponic system and the measured variables were root length and length of aerial part (LAP), number of roots (NR) and root dry matter (RDM) and aerial part dry matter (DMAP). The analysis of variance was performed, the relative performance calculated and linear regressions were fitted. Only the treatment effect for NR and effect of interaction for LAP were not significant. Root length was most affected by the acid and the regressions expressed positive as well as negative effects for acid tolerance in the mutant families.