Genotype x environment interaction for wheat yield in different drought stress conditions and agronomic traits suitable for selection

Abstract

Wheat cultivars grown in south-eastern Europe are exposed to variable rainfed environments. Climate change predictions indicate that the frequency of dry years will likely increase in the future. This study examined relationships among agronomic traits and some drought indices with grain yield as influenced by genotype and environment. In a 4-year experiment, 100 cultivars and landraces of bread wheat ( Triticum aestivum L.) from different countries were tested under 3 watering regimes: fully irrigated, rainfed, and in a rain-out plot shelter. Three selection indices, mean productivity ( MP), tolerance (TOL), and stress susceptibility index (SSI), were calculated based on grain yield in irrigated and drought-stressed conditions. The additive main effects and multiplicative interaction (AMMI) models were used to study the genotype x environment effects. Average yield reduction due to drought in the sheltered plots was 37.5%. High-yielding genotypes in each treatment showed high values of MP and high rank for SSI and, particularly, TOL. Conversely, low-yielding genotypes in each treatment had low values of MP and high drought tolerance according to SSI and TOL (i.e. low ranks). MP values were noted as being particularly well suited for predicting performance in this experiment. Total biomass and early vigour were found to be the most important agronomic traits for selecting high-yielding genotypes in a range of stress and non-stress conditions.