Abstract
The adverse effects of heat on plant yield strongly depend on its duration and the phenological stage of the crops when the heat occurs. To clarify the effects of these two aspects of heat stress, systematic research was conducted under controlled conditions on 101 wheat cultivars of various geographic origin. Different durations of heat stress (5, 10 and 15 days) were applied starting from three developmental stages (ZD49: booting stage, ZD59: heading, ZD72: 6th day after heading). Various morphological, yield-related traits and physiological parameters were measured to determine the stress response patterns of the wheat genotypes under combinations of the duration and the timing of heat stress. Phenological timing significantly influenced the thousand-kernel weight and reproductive tiller number. The duration of heat stress was the most significant component in determining both seed number and seed weight, as well as the grain yield consequently, explaining 51.6% of its phenotypic variance. Irrespective of the developmental phase, the yield-related traits gradually deteriorated over time, and even a 5-day heat stress was sufficient to cause significant reductions. ZD59 was significantly more sensitive to heat than either ZD49 or ZD72. The photosynthetic activity of the flag leaf was mostly determined by heat stress duration. No significant associations were noted between physiological parameters and heat stress response as measured by grain yield. Significant differences were observed between the wheat genotypes in heat stress responses, which varied greatly with developmental phase. Based on the grain yield across developmental phases and heat stress treatments, eight major response groups of wheat genotypes could be identified, and among them, three clusters were the most heat-tolerant. These cultivars are currently included in crossing schemes, partially for the identification of the genetic determinants of heat stress response and partially for the development of new wheat varieties with better heat tolerance.
Highlights
Global climate change is increasingly affecting crop production
Morphological traits were mostly determined by the genotype, which explained between 53.1% (LIN) and 83.9% (PH) of the phenotypic variance
Averaged over the 101 cultivars, the overall response to heat stress was a significant decrease in plant grain yield, the ratio of which worsened as the duration of the heat stress increased, regardless of the developmental phase in which heat was applied (Fig 1; for confidence intervals, see S2 Table)
Summary
Global climate change is increasingly affecting crop production. Especially temperature and rainfall anomalies, have a substantial influence on the success of cultivation. High temperature is one of the most frequent forms of abiotic stress, which represents a great danger to crop production. Extreme temperature events are expected to become more frequent in many main wheat-producing regions. These weather conditions can be characterised with short-term durations and temperature increases of over 5 ̊C above the normal temperature [1,2,3]. Increasing trends can be observed in the number of heat (Tmax 30 ̊C) and hot days (Tmax 35 ̊C) [4]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
