Germinação e crescimento de plântulas de genótipos de milho submetidos a simulação de déficit hídrico

Abstract

The drought phenomena have been one of the main elements that cause losses in agricultural production in Brazil, mainly in the initial phase of the formation of a plant stand in the culture of corn. Water stress is responsible for the lower germination speed and low uniformity in seedling emergence, being an important agent in the final grain yield in the field. Polyethylene glycol 6000 is one of the most used osmotic agents in research to simulate water deficit, as it is inert, does not present toxicity and does not penetrate the seed coat due to its high molecular weight. Within this context, the objective of the present work was to evaluate different maize genotypes in relation to germination and initial seedling development when exposed to different levels of water stress induced by polyethylene glycol 6000. Six maize cultivarswere evaluated, AG8690, FEROZ, AG8780, MG300, P3016VYHR and RB9060 regarding tolerance to water deficit induced by polyethylene glycol in osmotic potentials, 0; -0.2; -0.4; -0.6 MPa in laboratory conditions. A completely randomized design was used, with treatments distributed in a 6x4 factorial scheme (genotypes x osmotic potentials), with four replications. The variables evaluated were first germination count, germination, germination speed index, length of aerial part, radicle length, fresh mass of aerial part, fresh mass of radicle, dry mass of aerial part and dry mass of radicle. The corn genotypes showed different behavior regarding tolerance to the water stress condition, induced by polyethylene glycol 6000. The FEROZ, MG300 and P3016VYHR genotypes showed a higher tolerance to induced water stress, having presented a lesser reduction in the evaluated characteristics.