Improved cyber-physical system captured post-flowering high night temperature impact on yield and quality of field grown wheat

Abstract

Winter wheat (Triticum aestivum L.) is essential to maintain food security for a large proportion of the world’s population. With increased risk from abiotic stresses due to climate variability, it is imperative to understand and minimize the negative impact of these stressors, including high night temperature (HNT). Both globally and at regional scales, a differential rate of increase in day and night temperature is observed, wherein night temperatures are increasing at a higher pace and the trend is projected to continue into the future. Previous studies using controlled environment facilities and small field-based removable chambers have shown that post-anthesis HNT stress can induce a significant reduction in wheat grain yield. A prototype was previously developed by utilizing field-based tents allowing for simultaneous phenotyping of popular winter wheat varieties from US Midwest and advanced breeding lines. Hence, the objectives of the study were to (i) design and build a new field-based infrastructure and test and validate the uniformity of HNT stress application on a scaled-up version of the prototype (ii) improve and develop a more sophisticated cyber-physical system to sense and impose post-anthesis HNT stress uniformly through physiological maturity within the scaled-up tents; and (iii) determine the impact of HNT stress during grain filling on the agronomic and grain quality parameters including starch and protein concentration. The system imposed a consistent post-anthesis HNT stress of + 3.8 °C until maturity and maintained uniform distribution of stress which was confirmed by (i) 0.23 °C temperature differential between an array of sensors within the tents and (ii) statistically similar performance of a common check replicated multiple times in each tent. On average, a reduction in grain-filling duration by 3.33 days, kernel weight by 1.25% per °C, grain number by 2.36% per °C and yield by 3.58% per °C increase in night temperature was documented. HNT stress induced a significant reduction in starch concentration indicating disturbed carbon balance. The pilot field-based facility integrated with a robust cyber-physical system provides a timely breakthrough for evaluating HNT stress impact on large diversity panels to enhance HNT stress tolerance across field crops. The flexibility of the cyber-physical system and movement capabilities of the field-based infrastructure allows this methodology to be adaptable to different crops.

High night temperature effects on wheat and rice: Current status and way forward

“…Across the prototype (Hein et al, 2019) and large-scale field-based tents (Hein et al, 2020), days to flowering differed by only 6-8 days among the same set of 10 genotypes, indicating that differences in phenology were unlikely to be a major confounding factor in comparison across scales. In comparison to 2018, 2019 was a cooler year with the average ambient night temperature inside the control tents of the genotype SY Monument to be the best performer and the genotypes Larry and Tx86A56006 being second best across HNT treatments and scales (Figure 3).…”

“…Similar to the prototype study, HNT was imposed starting at 10 days after 50% flowering with the night temperature increased by +3.8°C compared to control tents. Across the prototype (Hein et al, 2019) and large‐scale field‐based tents (Hein et al, 2020), days to flowering differed by only 6–8 days among the same set of 10 genotypes, indicating that differences in phenology were unlikely to be a major confounding factor in comparison across scales. In comparison to 2018, 2019 was a cooler year with the average ambient night temperature inside the control tents of 18.4°C (large‐scale heat tents; Figure 1f), while it was 22.7°C under ambient conditions (Figure 1e) in 2018.…”

“…In 2019, the prototype was expanded to accommodate 320 accessions of a winter wheat diversity panel, wherein the same set of 10 winter wheat genotypes were included in all six large‐scale field‐based heat tents, each of 9.1 m width, 14.6 m length and 4.4 m height (Figure 1c). Compared to the 2018 field‐based prototype study, wherein the control night temperature treatment was in the open field (without any covered tents), the 2019 study was carried out using three HNT and three control large‐scale heat tents (Hein et al, 2020). This allowed the authors to have the exact infrastructure and growth conditions across all the tents, keeping all other factors similar except the HNT stress exposure (Figure 1c).…”

“…Average grain yield of 10 winter wheat genotypes grown under different night temperature treatments using (a) controlled environment chambers, (b) small‐scale field‐based heat tents and (c) large‐scale field‐based heat tents. Stress imposition protocols and genotypic responses to high night temperature (HNT) treatments from the controlled environment chambers, small scale field‐based heat tents and large scale field‐based heat tents can be obtained from Impa et al (2020), Hein et al (2019) and Hein et al (2020), respectively. Percent values above/below the boxes indicate percent reduction under HNT treatments compared to (a) lower night temperatures or (b, c) control temperatures.…”

Physiological and molecular attributes contribute to high night temperature tolerance in cereals

“…Extensive efforts are taken to improve the reproducible experimental setup of HNT conditions to characterize natural variation. Cereals were grown using overhead infrared heaters in greenhouse experiments (Mohammed & Tarpley, 2009c), in situ temperature‐controlled field chambers (S. Chen et al, 2013) and tents with heaters and ventilation under field conditions (Hein et al, 2019; Hein et al, 2020). Recent reviews compare the quantification of HNT responses on grain yield in controlled environmental chambers versus field experiments (Impa et al, 2021) and summarize methods in thermal tolerance research (Geange et al, 2020).…”