Crop mixtures: Does niche complementarity hold for belowground resources? An experimental test using rice genotypic pairs

Aims: 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. Methods: 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. Results: 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. Conclusions: 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.

Bibliographic Details

Main Authors:	Montazeaud, Germain, Violle, Cyrille, Fréville, Hélène, Luquet, Delphine, Ahmadi, Nourollah, Courtois, Brigitte, Bouhaba, Ilyas, Fort, Florian
Format:	article biblioteca
Language:	eng
Subjects:	F30 - Génétique et amélioration des plantes, F08 - Systèmes et modes de culture, Oryza sativa, culture en mélange, lignée, génotype, interactions biologiques, évaluation de l'impact, système racinaire, rendement des cultures, synergisme, mélange de semences, variété, http://aims.fao.org/aos/agrovoc/c_5438, http://aims.fao.org/aos/agrovoc/c_4871, http://aims.fao.org/aos/agrovoc/c_29225, http://aims.fao.org/aos/agrovoc/c_3225, http://aims.fao.org/aos/agrovoc/c_49896, http://aims.fao.org/aos/agrovoc/c_37938, http://aims.fao.org/aos/agrovoc/c_16034, http://aims.fao.org/aos/agrovoc/c_10176, http://aims.fao.org/aos/agrovoc/c_16149, http://aims.fao.org/aos/agrovoc/c_6935, http://aims.fao.org/aos/agrovoc/c_8157, http://aims.fao.org/aos/agrovoc/c_4188, http://aims.fao.org/aos/agrovoc/c_3840, http://aims.fao.org/aos/agrovoc/c_3081,
Online Access:	http://agritrop.cirad.fr/586334/ http://agritrop.cirad.fr/586334/7/s11104-017-3496-2.pdf
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