Starch properties of field-grown malting barley under variable weather: Interpreting results in light of controlled-environment studies

Abstract

In this study, six malting barley varieties were cultivated under seven different environmental field conditions in 2022 and 2023. Temperature and precipitation data before and during kernel development were recorded and correlated with measured starch properties like gelatinization behavior (DSC) and starch granule size distribution/B-granule proportion (laser diffraction). The results were used to evaluate the extent to which previous findings from controlled-environment experiments are transferable to real-world field cultivation, focusing on the impact of (i) drought, (ii) temperature during kernel development, (iii) pre-anthesis temperature, and (iv) the variety-dependency of resulting starch properties.

As found in previous controlled-environment studies, field data could not confirm a starch granule size reducing effect of drought on malting barley. High temperatures during kernel development, particularly nighttime temperatures, significantly influenced starch gelatinization behavior by correlating positively with T₀ (0.493) and T_P (0.486). Pre-anthesis temperature negatively correlated with starch granule size (up to −0.699 for Dx50) and starch transition enthalpy (up to −0.543), partially supporting controlled-environment findings. Starch gelatinization properties showed variety-specific responses to environmental conditions, highlighting breeding potential for climate-resilient barley. This study establishes the basis for predicting starch properties based on weather data and specifically emphasizes the critical role of nighttime temperatures during kernel development in influencing gelatinization behavior.