Tolerância à seca de genótipos de trigo utilizando agentes indutores de estresse no processo de seleção

Abstract

The aim of this study was to select wheat genotypes tolerant to drought by inducing water deficit using different osmotic agents. Seeds and immature embryos of eight wheat genotypes were subjected to different osmotic gradients and evaluated for shoot length, main root and total biomass production. Seeds were subjected to the osmotic agents polyethyleneglycol-6000 and mannitol in seven osmotic gradients and evaluated after 10 days. The embryos were cultured in potato medium supplemented with PEG 6000, mannitol and maltose at the concentrations of 10%, 20% and 30%, plus a control, and evaluated after 30 days of incubation. The experimental design was completely randomized and data submitted to regression analysis using the "t" test to compare the Beta values and analysis of variance with test of means by "t" test. There was effect of water stress on all genotypes tested for the seedlings originated from seeds, with significant interaction between osmotic agent and genotype and greater negative effect for PEG 6000. Genotypes BH 1146 and Ocepar 14 showed the highest tolerance to drought and mean reduction in growth, in the presence of stressors, of 58% and 62%, respectively. In contrast, the genotype Alliance was the most sensitive with an average reduction in growth of 92%. For seedlings derived from immature embryos, the genotype BH 1146 also showed relative tolerance, but Alliance and Ocepar 14 were highly sensitive. However, these genotypes also showed poor performance in the culture medium without the presence of stressors, thus, the negative effect may be due to the in vitro culture.