Crop mixtures: does niche complementarity hold for belowground resources? An experimental test using rice genotypic pairs
- 215 Downloads
Genotypic mixtures have been receiving a growing interest as genetic diversity could increase crop productivity. Resource-use complementarity is an expected key underlying mechanism, provided that varieties in the mixture differ in resource-related traits, notably root traits. We aimed at examining how trait differences and resource-use complementarity drive biomass production of genotypic mixtures.
Four rice (Oryza sativa) genotypes including two Near-Isogenic Lines only differing in root depth were grown in monoculture and in two-way mixtures in pots under two levels of phosphorus supply. We analyzed the relative difference between mixture biomass and the best monoculture biomass in relation to between-genotype phenotypic distance on ten resource-related traits.
Mixtures never outperformed the best monoculture. However, relative mixture productivity increased with increasing between-genotype distance in biovolume, specific leaf area and top soil root biomass. This was mainly driven by a “selection effect”: trait differences led to competitive ability differences and the dominant genotypes tended to gain more in mixture than the subdominant genotypes lost compared to monoculture.
Rather than trying to minimize competition through resource-use complementarity, we argue that promoting interactions between genotypes that have different competitive abilities may be a more promising approach to design productive crop mixtures.
KeywordsCrop mixture Functional diversity Near-isogenic lines Resource-use complementarity Rice Root traits Selection effect
This work was funded by the European Research Council (ERC) Starting Grant Project “Ecophysiological and biophysical constraints on domestication in crop plants” (Grant ERC-StG-2014-639706-CONSTRAINTS). We thank Clemence Darley for her dedicated technical help and the ‘Terrain d’expériences’ and ‘PACE’ platforms at CEFE (technical facilities of the Labex Centre Méditerranéen de l’Environnement et de la Biodiversite, CEMEB) for providing all the facilities and technical support.
- Core Team R (2017) R: a language and environment for statistical computing. R Found. Stat, ComputGoogle Scholar
- Cornelissen JHC, Lavorel S, Garnier E, Díaz S, Buchmann N, Gurvich DE, Reich PB, Ter Steege H, Morgan HD, Van Der Heijden MG a et al (2003) A handbook of protocols for standardised and easy measurement of plant functional traits worldwide. Aust. J Bot 51:335Google Scholar
- Craven D, Isbell, F, Manning P, Connolly J, Bruelheide H, Ebeling A, Roscher C, van Ruijven J, Weigelt A, Wilsey B et al (2016) Plant diversity effects on grassland productivity are robust to both nutrient enrichment and drought. Philos Trans R Soc B Biol Sci 371Google Scholar
- Hutchinson GE (1957) The multivariate niche. Cold Spring Harbor Symposia on Quantitative Biology, In, pp 415–421Google Scholar
- Kunstler G, Lavergne S, Courbaud B, Thuiller W, Vieilledent G, Zimmermann NE, Kattge J, Coomes DA (2012) Competitive interactions between forest trees are driven by species’ trait hierarchy, not phylogenetic or functional similarity: implications for forest community assembly. Ecol Lett 15:831–840CrossRefPubMedPubMedCentralGoogle Scholar
- Mommer, L., Visser, E.J.W., Ruijven, J. van, Caluwe, H. de, Pierik, R., and Kroon, H. de (2011). Contrasting root behaviour in two grass species: a test of functionality in dynamic heterogeneous conditions. Plant Soil 344, 347Google Scholar
- Olsen, S.R. (1954). Estimation of available phosphorus in soils by extraction with sodium bicarbonate (United States department of agriculture; Washington)Google Scholar
- Schmid B, Niklaus PA (2017) Biodiversity: complementary canopies. Nat. Ecol. Evol. 1:0104Google Scholar
- Wagg C, Ebeling A, Roscher C, Ravenek J, Bachmann D, Eisenhauer N, Mommer L, Buchmann N, Hillebrand H, Schmid B et al (2017) Functional trait dissimilarity drives both species complementarity and competitive disparity. Funct Ecol. https://doi.org/10.1111/1365-2435.12945
- Williams, L.J., Paquette, A., Cavender-Bares, J., Messier, C., and Reich, P.B. (2017). Spatial complementarity in tree crowns explains overyielding in species mixtures. Nat Ecol Evol 1, 0063Google Scholar
- Yoshida S, Hasegawa S (1982) The rice root system: its development and function. In: Drought resistance in crops with emphasis on rice. Int. Rice Res. Inst., Los BañosGoogle Scholar
- Zhu, G., Peng, S., Huang, J., Cui, K., Nie, L., and Wang, F. (2016). Genetic Improvements in Rice Yield and Concomitant Increases in Radiation- and Nitrogen-Use Efficiency in Middle Reaches of Yangtze River. Sci. Rep. 6, srep21049Google Scholar