Seleção de genótipos de milho com restrição hídrica no florescimento

Abstract

Agriculture's main challenge is to meet the growing demand for food, due to the constant increase in global consumption and climate change. Maize breeding programs seek to develop more productive genotypes that are adaptable to different climatic conditions, including hybrids that are tolerant to water restriction. Diallel analysis makes it possible to understand additive and non-additive genetic effects, helping to define the most appropriate breeding strategy. This study sought to select maize genotypes for responsiveness to water restriction during flowering, evaluated in experiments with full irrigation and water restriction. Crosses were made in a partial diallel scheme (4 x 6), using ten partially inbred progenies. The experiments were conducted in randomized complete blocks, with three replications, in the second harvest, in Lavras-MG, in the year 2023, under two environmental conditions. Traits such as male flowering (FM), female flowering (FF), flowering interval (IF), stay-green (SG), prolificacy (PROL) and grain yield (PG) were evaluated. The diallel analysis followed the model proposed by Griffing (1956) adapted. Phenotypic adaptability analysis was based on graphical dispersion. The SCC contributed most to the composition of the sum of squares of the treatment. Genitors L1, L2 and L1', L2', L4' proved to be good general combiners for reducing the cycle and increasing PROL. The hybrid combinations L1xL3', L2xL6' and L4xL1' showed high and negative estimates of CEC and average heterosis for reducing FM, FF, IF. Hybrids L2xL3', L2xL5', L3xL2', L4xL5' and L3xL6' showed high and positive CEC estimates and average heterosis for PROL, PG, male and female flowering synchrony and were late.Genotypes G13, G17 and G18 responded better to irrigation and are recommended for the harvest, G6, G12 and G24 for the off-season and G9, G11, G14, G16 and G23 showed wide adaptability, being early and with good grain yields. It was possible to select five inbred progenies, eight genotypes with the potential to start a maize breeding program for tolerance to water restriction.