The effects of heading time on yield performance and HvGAMYB expression in spring barley subjected to drought

Abstract

Abstract In the lifetime of a plant, flowering is not only an essential part of the reproductive process but also a critical developmental stage that can be vulnerable to environmental stresses. To ensure survival during drought, plants accelerate the flowering process, and this response is known as „drought escape”. HvGAMYB – transcriptional factor associated, among others, with flowering process and anther development in barley has also an important role in developmental modification and yield performance in plants subjected to stressed conditions. However, there is limited information whether the mechanisms associated with the flowering acceleration may cause the anther or pollen disruption due to their influence on flower development via GAMYB overexpression. The aim of this study was to characterize differences in responses to drought among barley genotypes varied in terms of earliness. Two subgroups of barley plants differentiated in terms of phenology were analyzed, and a wide range of traits linked to plant morphology, physiology, and yield were investigated. The abiotic stress reactions of two barley plants subgroups varied in our study both in terms of yield, morphology, chlorophyll fluorescence kinetics and pollen viability. The results extend our knowledge about HvGAMYB expression in anthers of barley plants grown under drought conditions and indicate the role of this transcription factor in shaping the yield via influencing traits linked to spike morphology, especially in lateral stems. Hence, this gene could be regarded as an important factor in flowering process and, as a consequence, pollen and seed development in plants subjected to abiotic stress conditions. This study clearly show the important role of HvGAMYB in survival mechanism associated with so called “drought escape strategy”.