klimazwei - Weizen

Climate Change Adaptation of Wheat Production in Germany through Plant Breeding

Background

Global climate change has considerable impacts on local environments. While global mean temperature is expected to increase by 2-5°C over the next decades, specific regional impacts in Germany can only be assessed with regional climate models, related case studies and sensitivity analyses. Some regions will on average become drier, while others will face higher precipitation levels. Timely adaptation of agricultural crops to long-term climate trends through plant breeding requires investment in research and development for a targeted utilisation of their genetic potential.

Research aims

This project focuses on hexaploid bread wheat due to the leading

Weizen

position of wheat regarding the area harvested as well as the production in Germany and Europe and its central importance for food and feed production. In addition, the trade with wheat plays an important role based on the predicted increasing demand on international agricultural markets. The summer 2003, with a continuing heat period, revealed that the expected climate change can result in considerable long-term yield losses. The stabilisation of yield as well as the increases in productivity will in future be sustained predominantly by the development of new varieties. During the last years, the annual increase in production, especially in the more continental climate of Bavaria, was nearly found at zero.

A major reason therefor might be the increasing drought in early summer, which leads to an early termination of the grain filling period. A continuous detraction of the wheat production in Germany by changed climatic conditions will also have serious economical effects. The precocious adaptation to expected climatic changes by plant breeding should provide the requirement for the development of varieties with a good resistance to abiotic stress. The objective of this project is to find a cost-effective possibility for the adaptation to climate change in the context of plant breeding research. A main focus lies on the pre-drawing of flowering time in winter wheat to deal with early summer drought. It will be investigated, if new varieties with an earlier flowering time achieve an advantage in competition in wheat production, when grown under changed climatic conditions, and if positive effects on a sustainable production system can be expected.

The two main focuses of this project are:

(1) The need for climate change adaptation in wheat production in Germany until 2030 to 2050.

In order to determine the pressure of adaptation of the wheat production in Germany global climate predictions are used to develop locally restricted climatic scenarios with a very high spatial resolution. The aggregated results of the different models and especially the regional and seasonal distribution of precipitation, temperature and radiation are to some extent uncertain. Several various regional climate simulations are going to be analyzed and their results will be compared with the present climatic conditions to estimate the certainty of the simulated climate change. Various climate scenarios will be used to force a dynamic vegetation model. In this manner the effect to the crop of wheat will be assessed. The simulated change will be described by appropriate stress indicators.

Spatially explicit production effects will be aggregated for all of Germany, in order to calculate the supply effects on domestic markets. For the assessment of additional trade effects and long-term changes on international commodity markets we will use a number of scenarios. As a result, the economic impacts of climate change for wheat production in Germany can be derived. Product quality effects and agricultural employment effects will be captured in consistent side calculations.

(2) The potential of plant breeding to develop wheat varieties adapted to climate change.

Our focus is to develop wheat varieties adapted to the abiotic stress complex heat/drought. In this context we will examine early flowering as an escape mechanism to counteract increasing early summer drought stress in Germany. Three groups of genes are well-known to be involved in controlling flowering time of wheat. Photoperiod response genes (Ppd), vernalisation genes (Vrn) and earliness per se genes (Eps) are essential in the phasic development of wheat.

Conscious selection for these photoperiod response genes in plant breeding programs will yield varieties with better adaptation to future climate conditions. In order to determine the potential of early flowering in wheat, a wide range of germplasm from all over the world showing considerable genetic variation in flowering time is being examined. This set of wheat lines will be analysed with molecular markers to determine which known genes are present. In parallel we will develop doubled haploid mapping populations to identify new monogenic as well as quantitative loci with an influence on flowering time. In addition, all plant material under molecular examination will be phenotypically characterized in field trials and in the greenhouse. This plant material will be used to combine most suitable loci for early flowering which eventually will be transferred into modern winter wheat varieties.
It will also be investigated, if new wheat varieties with an earlier flowering time show positive production effects under changing climate conditions. Adaptation potential through crop substitution within the EU as well as through trade with third countries will also be assessed.