Grain micronutrient composition and yield components in field-grown wheat are negatively impacted by high night-time temperature

Authors: HEIN, NATHAN - Kansas State University; IMPA, SOMAYANDA - Kansas State University; WAGNER, DAN - Kansas State University; KUMAR, RITESH - Kansas State University; TIWARI, MANISH - Kansas State University; PRASAD, VARA - Kansas State University; BHEEMANAHALLI, RAJU - Kansas State University; Tilley, Michael - Mike; Wu, Xiaorong; NEILSEN, MITCHELL - Kansas State University; JAGADISH, KRISHNA - Kansas State University

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/31/2021
Publication Date: 12/31/2021
Citation: Hein, N.T., Impa, S.M., Wagner, D., Kumar, R., Tiwari, M., Prasad, V., Bheemanahalli, R., Tilley, M., Wu, X., Neilsen, M., Jagadish, K. 2021. Grain micronutrient composition and yield components in field-grown wheat are negatively impacted by high night-time temperature. Field Crops Research. 99(3):615-624. https://doi.org/10.1002/cche.10523.
DOI: https://doi.org/10.1002/cche.10523

Interpretive Summary: Wheat (Triticum aestivum L.) is a major staple crop supporting about 35% of the world population. Wheat and wheat products, on average, supply nearly 550 kcal capita-1 day-1 which accounts for '20% of the average daily caloric intake. The average caloric intake is projected to reach 3000 kcal capita-1 day-1 and the world population would increase by over 2 billion by 2050 compared to 2018. This increase in population and average daily caloric intake creates rapidly increasing demand for wheat through 2050. To accomplish this increase in production, factors that affect yield, including nutrient and water, solar radiation, fertilizer, genotype, and temperature responses, need to be optimized. While water availability can be augmented with supplemental irrigation and management practices can help maximize the benefits of fertilizer with appropriate genotype selection, addressing adverse impacts of temperature extremes are challenging. Heat events can be highly detrimental to yield when they coincide with vulnerable developmental stages such as grain-filling. High night-time temperature (HNT) stress has been shown to be detrimental to yield in many different crops including rice (Oryza sativa L.), barley (Hordeum vulgare L.), soybean, and cotton (Gossypium arboreum L.). Based on the quantification of the negative impact of HNT on field grown rice, efforts to determine impact of HNT on wheat were conducted using controlled environment growth chambers. These studies revealed sensitive growth stages when HNT begins to affect wheat, evaluated changes in grain protein, starch, and lipid accumulation, but have not evaluated the dynamics related to grain macro- and micro-nutrient composition. To achieve this objective, 12 diverse hard winter wheat genotypes were grown in field-based custom-built heat tents that retained natural light and temperature conditions during the day and imposed elevated temperature by 3.2°C throughout the grain-filling period. HNT stress reduced 200 grain weight by 1.9% per °C, grain yield by 3.1% per °C, seed starch content by 2.48% per °C, and seed protein content by 3.64% per °C increase in night-time temperature as compared to control conditions. HNT had significant negative effect on grain macro- and micro-nutrient content. Starch and protein concentrations, however, were differentially correlated with grain nutrient concentration 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 environments.

Technical Abstract: Wheat (Triticum aestivum L.) a major temperate cereal 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. With global climate models predicting a continued and steady increase in HNT in the future, our major objective was to ascertain the changes in grain macro- and micro-nutrient composition and yield-related parameters, on exposure to HNT during grain filling. To achieve this objective, 12 diverse genotypes were grown in field-based custom-built heat tents that allowed to retain natural light and temperature conditions during the day and impose stress during night-time. The field-tents equipped with Raspberry Pi cyber-physical system, effectively imposed 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% per °C, grain yield by 3.1% per °C, seed starch content by 2.48% per °C, and seed protein content by 3.64% per °C increase in night-time temperature as compared to control conditions. HNT had significant negative effect on grain macro- and micro-nutrient content. Starch and protein concentrations, however, were differentially correlated with grain nutrient concentration 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.