Genetic improvement of sown grasslands in the face of climatic hazard: promoting diversity – PRAISE

Effect of interactions between genotypes within and among species, must be taken into account in the selecting processes for improving the production and the persistence of pluri-specific grasslands submitted to climatic changes. Incorporating diversity into plant breeding requires taking into account the influence of inter- and intra-specific interactions at the community level that in fine, impact the production of forage. To reach that aim, when developing plant breeding procedures, it is necessary to take into account the variability in responses of genotypes and their change in dynamics along time. The associated scientific and methodological challenges are related to the scaling-up of individual properties to population and community levels, and to the analysis and understanding of correlations occurring among characters of interest. The project PRAISE addresses these challenges by:

(i) developing a pluri-disciplinary approach : quantitative genetics and ecophysiology for analyzing the response of characters of individuals; functional community ecology and ecophysiology for scaling plant characteristics up to the level of populations and communities; population genetics for characterizing the dynamics of the intra-specific genetic variability in response to selection.
(ii) combining experiments and models for analyzing and understanding the distribution of characters. Characters under study are morphological, functional or ecophysiological and are directly or indirectly linked to plant fitness and performance. Coupling individual-centered models and the functional diversity approach seems to be particularly relevant for taking into account the impact of the intra-specific genetic diversity in the production of pluri-specific mixtures.

results to come

future prospect to come

-Litrico I. & Violle C. (2015) Diversity in plant breeding: a new conceptual framework. Trends in Plant Science (in press. DOI: 10.1016/j.tplants.2015.07.007 )

-Prieto I., Violle C., Barre P., Durand J.L., Ghesquiere M., Litrico I., (2015). Complementary effects of species and genetic diversity on productivity and stability of sown grasslands. Nature Plants, 1, 4

A grand challenge for agriculture is to adapt current intensive or semi-intensive production systems in the face of global change. Indeed such systems need to be re-designed to cope with increasing drastic environmental changes, especially increasing frequency of extreme and hazardous climatic events. Traditional genetic improvement is based on the built-in of ideotypes characterized by reduced, or null, genetic variability (pure lines) and grown in monoculture. Even if efficient and necessary, this approach cannot fully respond to future avenues related to the sustainability of agronomic covers and the interannual stability of their biomass production in the face of increasing intra- and interannual variability of water deficits. Current production systems are characterized by reduced sown genetic diversity via the widespead use of species grown in monoculture only, while several ecological studies have demonstrated the plus-value of taxonomic and genetic diversity for the stability of biomass production in response to environmental changes. Promoting specific diversity of agricultural covers may allow to better coping with environmental hazards while challenging environmental avenues for agriculture (reduction of inputs, maintenance of wild biodiversity etc.). Here is the working hypothesis for PRAISE.

The use of cultivated species in mixture implies important changes for varietal selection. Genetic improvement of cultivated species for a use in mixture also remains to be developed. Indeed the response of a variety grown in isolation or in mixture may be decoupled given the complex interaction effects among neighbouring plants within a mixture. To reach these objectives, we advocate the need for a drastic change of paradigm for varietal selection. Accounting for genotypic interactions within- and among-species, via the analysis if intra- and interspecific trait distribution, is a necessary step for a renewal of selection schemes so as to improve the production and sustainability of crops in the face of environmental hazards.
PRAISE is focused on sown temporary and plurispecific grasslands. This type of covers plays a major role as part of sustainable agriculture. Up to now, the genetic (within- and among-species) diversity of such a cover has been poorly examined and exploited. PRAISE aims at studying and promoting this diversity.

The overall goal of PRAISE is to pave the road of a renewed genetic improvement of grassland species involved in mixture based on genetic and ecological knowledge in a context of increasing environmental hazards. More specifically, we aim at: (i) identifying the best varietal composition of mixtures, and the related genetic and ecological conditions of application, which maintain high and stable production of plurispecific grasslands over time; (ii) provide the theoretical bases of an innovative selection schema of forage grassland species for a use in mixture.
PRAISE is a pluridisciplinary project at the crossroad of quantitative genetics, ecophysiology, functional ecology and population and ecology. Together, we will develop a renewed selection schema involving genetic and taxonomic diversity. As a perspective, this schema may be applied to other types of cultivated species, including field crops which are also facing big environmental challenges.