Better performance of organic than conventional tomato varieties in single and mixed cropping

ABSTRACT

Replacing traditional crop varieties with commercial, high-yielding varieties during the last decades is one of the main drivers for the decline in farmland and crop diversity. However, it is unclear how commercial, high-yielding varieties adapt to less environmental conditions such as weed pressure and mixed cropping cultivation systems. In Europe, organic breeding organizations conserve local, traditional varieties and develop new varieties under low-input conditions, aiming at increasing the range of varieties adapted to harsh cultivation conditions and mixed cropping. To evaluate whether organic varieties (i) cope better with weed pressure and (ii) have a higher adaptability to mixed cropping, we compared the agronomic and quality performance of eight organic varieties with eight commercial, high-yielding varieties, focusing on tomato, the economically most important vegetable in the EU. Each group was cultivated as single plants and in a mixed cropping system, respectively, with a legume and with or without exposure to weed stress by a grass. The organic group outperformed the commercial, high-yielding group, specifically, in mixed cropping systems. Weed stress lowered the yield of both groups, but the organic group showed higher fruit weight stability across the varieties than the commercial, high-yielding varieties when grown as single plants under weed stress.

KEYWORDS:

• Agrobiodiversity
• genetic diversity
• organic breeding
• variety comparison
• vegetable diversity
• weed stress

Data available statement

The raw data supporting the conclusions of this study will be made available by the authors, without undue reservation.

Acknowledgments

The authors acknowledge Prof. Stefanie Sievers-Glotzbach, the head of the RightSeeds project, in which this experimental study is embedded. We thank her and the RightSeeds working group for inspiration and support. We thank the experimental botanical garden of the University of Göttingen, led by Lars Köhler und Dietrich Hertel, and especially Regina Helbig and Gabi Kuchenbuch for knowledge and support cultivating the plants. Also, we are grateful to Julia Morley, Johanna Friedrich, and Susanne Jahn for assistance in cultivation and harvest. Furthermore, we are grateful for the collaboration and consultancy of the Agroecology Group and ZfS Statistical Consulting, Dr. Laura Sutcliffe for English proofreading as well as the valuable comments of Dr. Steve Gliessmann and the anonymous reviewers helping to improve the paper.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

A.M.F., J.L., and T.T. developed the methodology and the experimental design. A.F. performed the experiment. A.M.F., J.L., and T.T. wrote and edited the manuscript. A.M.F., J.L., and T.T. read carefully and approved the final version of the manuscript.

Additional information

Funding

This work was supported by the Federal Ministry of Education and Research of Germany in the field of Research for Sustainable Development under (Grant No. Bundesministerium f?r Bildung und Forschung 01UU1602B).