Grain Micronutrient Composition and Yield Components in Field-grown Wheat Are Negatively Impacted by High Night-time Temperature

Hein, N. T., Impa, S. M., Wagner, D., Bheemanahalli, R., Kumar, R., Tiwari, M., Prasad, P. V. V., Tilley, M., Wu, X., Neilsen, M., & Jagadish, S. V. K. (2022). Grain Micronutrient Composition and Yield Components in Field-grown Wheat Are Negatively Impacted by High Night-time Temperature. Cereal Chemistry. ., .DOI:10.1002/cche.10523.

Wheat (Triticum aestivum L.) is highly vulnerable to heat stress during sensitive growth and developmental stages, including grain-filling. The impact of high daytime heat stress on wheat yield and quality losses has been extensively investigated, while information related to high night-time temperature (HNT) is limited. The major objective was to ascertain the changes in wheat grain macro- and micro-nutrient composition and yield-related parameters on exposure to HNT during grain-filling. Twelve diverse genotypes were grown in field-based custom-built heat tents that allowed natural light and temperature conditions during the day and imposed stress overnight. The field-tents imposed a 3.2°C higher night-time temperature compared to ambient conditions throughout the grain-filling period. HNT stress reduced 200 grain weight by 1.9%, grain yield by 3.1%, seed starch content by 2.5%, and seed protein content by 3.6% per °C increase in HNT. HNT had significant negative effect on grain macro- and micro-nutrient content. However, starch and protein concentrations were differentially correlated with grain nutrients, with starch negatively correlated with many of the micronutrients under control and HNT. This negative correlation highlights the imperative balance of seed micronutrient composition that needs to be maintained as efforts are intensified to enhance grain yield under favorable and warming environments.