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

Abstract

Drought phenomena have been one of the main causes of losses in agricultural production throughout Brazil, and in the initial phase the conditions of water deficit are responsible for the formation of the final stand of plants. Water deficit causes a reduction in the length of the aerial part of wheat, it also decreases the size of the radicle and decreases the germination speed index, water is considered as the main environmental factor that regulates the growth and development of plant species. Environmental stresses trigger diverse responses in plants, ranging from changes in gene expression and cellular metabolism to changes in plant growth rate and productivity. Mannitol 20% is commonly used as an osmotic agent to simulate conditions of water deficit in different works and different cultures, and this is justified because mannitol is a chemically inert and non-toxic compound. Therefore, the objective of this work was to evaluate different wheat cultivars in relation to germination and initial seedling development when exposed to water deficit conditions induced by 20% mannitol. Four wheat cultivars, ORS Madre Pérola, BRS Reponte, BRS Tarumã and TBIO Ponteiro, were evaluated for tolerance to water deficit under laboratory conditions. A completely randomized experimental design was used, with treatments distributed in a 4 x 2 factorial scheme (cultivars x treatment), with three replications. The analyzed variables were first germination count, germination, germination speed index, shoot length and radicle length. Cultivar ORS Madre Pérola had the highest average for shoot length and cultivar BRS Reponte had the highest average for radicle length.