Heat tolerance during pollen development of maize and wheat

Background and Goals

This project is the fourth subproject of the project "BayKlimaFit - strategies for adapting crops to climate change".

The goal of this project is to identify the critical phases of pollen development in the crop plants wheat and maize when pollen sterility occurs at short high temperature conditions with adequate water supply. Using cytological and physiological methods pollen development will be compared with and without heat stress episodes using heat sensitive and heat tolerant genotypes. In the long term the understanding of the molecular mechanism(s), which lead to heat tolerance during pollen development, will enable the selection of heat stress tolerant crop and wild plants.

Content time


Research area/region

  • Germany
Region of implementation (all German federal states)
  • Bavaria

Steps in the process of adaptation to climate change

Step 1: Understand and describe climate change

Approach and results 

Climate change also leads to a significant increase in the average temperature in Bavaria in the summer months and in particular to a strong increase in weather extremes.
The summer temperatures in Bavaria in 2015 have increased on average from the long-term average of the years 1961-1990.

Parameter (climate signals)
  • Heat waves

Step 2a: Identify and assess risks - climate effects and impact

Approach and results 

Short high-temperature episodes (KHTs) for 1-3 days above a critical temperature (KT) have a major impact on pollen sterility in cultivated and wild plants. KHTs induce sterile pollen, leading to absent seed formation (up to 50% seed yield loss).

The subproject dealt with the agronomically important crops maize and wheat and investigated which pollen development phases are particularly critical for short heat stress periods over two to three days. It could be shown that the meiosis and tetrad stages are particularly sensitive. Using physiological methods, high-throughput sequencing (RNA-seq) and metabolite analyzes, u. a. It can be shown that Bavarian wheat varieties overreact to heat stress in comparison to Australian varieties and that the sugar and lipid balance in maize changes during heat stress during pollen development. As a result, pollens can not germinate and are sterile. Gene regulators were identified that could play a role in the transition of the respective developmental phases and control heat stress regulated genes. Several genes for transcription factors have been selected for so-called genome editing. The exact functions of the selected genes could not be investigated during the project period.


Funding / Financing 

Bavarian State Ministry of the Environment and Consumer Protection

Project management 

University of Regensburg

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