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L'Unité Expérimentale de Gotheron développe des programmes d'expérimentation-recherche sur les systèmes de production durable en  ARBORICULTURE  fruitière (abricotiers, pêchers, pommiers, poiriers). © MAITRE Christophe

Water and agriculture

Drought-tolerant plant varieties  

Droughts, aggravated by heat waves, are likely to be more frequent in the future. However, they will remain difficult to predict, making them difficult to prepare for. Farmers can deal directly with this issue by choosing plant varieties that tolerate less water.  

Many of INRA’s research programmes focus on developing drought-tolerant plant varieties. However, adapting plants to droughts involves complex and interdependent traits, which each involve several genes.

 

There is no miracle gene

 

“There are no good or bad traits for tolerance,” explains François Tardieu, research director at the Laboratory of Plant Ecophysiological Responses to Environmental Stresses (INRA Montpellier). “It all depends on the climate scenario and soil characteristics.”

 

For example, an increase in root development is only positive if it allows the plant to absorb more water. If this is not the case, the cost of these roots in carbon can harm yield. Similarly, during moderate water stress, continued leaf growth encourages photosynthesis and therefore better yields. In drier conditions, this trait, which also leads to high levels of evapotranspiration, can cause water in soil to be used up more quickly and even the death of plants. As the researcher underlines, “We will never be able to produce plants that maintain their productivity without a high level of transpiration. We therefore have to find a compromise between protection and productivity.” Consequently, genetic improvement must take into account plants’ overall reaction to a lack of water in all pedoclimatic conditions (including different dates, different drought intensities and frequencies, different depths of soil, etc.).

 

Many genotypes must therefore be tested

As part of the European DROPS* project (2010-2015), INRA and fifteen private and public partners will develop a methodology for association genetics. This newly developed methodology will make it possible to test a large number of genotypes and access complex traits without sequencing all genes. It involves statistical associations between trait variations (phenotypes) and genome variations, thanks to high throughput phenotyping and genotyping methods. The programme will focus on maize, hard wheat and soft wheat. The traits dealt with include the growth of leaves and reproductive organs, seed abortion rates, root system architecture and water use efficiency (biomass/transpiration ratio). The data obtained will be used in a model for the functioning of crops, which can simulate the overall reaction of plants depending on their genetic characteristics and the climate. These tools and methods will allow breeders to create varieties that are more tolerant to water stress and/or more efficient in using water, in addition to being better adapted to future pedoclimatic conditions in Europe.

*Drought-tolerant yielding plants.