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Effects of intra-variety root competition and soil fertility on resource allocation in a modern wheat variety and an old landrace
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  • Li Zhu,
  • Jun Xiang,
  • Da-Yong Zhang,
  • Wei Wang,
  • Bao-Zhong Wang,
  • You-Cai Xiong
Li Zhu
Huanggang Normal University
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Jun Xiang
Huanggang Normal University
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Da-Yong Zhang
Beijing Normal University
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Wei Wang
Lanzhou University
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Bao-Zhong Wang
Lanzhou University
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You-Cai Xiong
Lanzhou University

Corresponding Author:[email protected]

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Abstract

Darwinian agriculture (also called Evolutionary agroecology) which focuses on the trade-off between individual fitness and community performance, can provide an efficient approach to enhance crop production. However, evolutionary or ecological processes, in particular the tragedy of the commons in crops, remain poorly understood. We used a pot experiment to examine whether wheat plants fell into this ‘tragedy’ when confronted with roots of an intra-variety neighbour and how the magnitude was influenced by soil fertility. Two varieties (old landrace Monkhead and modern variety 92-46) were selected for this study. Root competition scenarios were set by growing two plants of the same variety with a mesh or plastic partition. Soil fertility gradients were set by adding nutrient solutions with low or high application frequency. Biomass were tested and allometric relationship were analyzed to reveal resource allocation pattern. Old Monkhead had similar relative allocation to root biomass with modern 92-46, but had greater relative allocation to stem&leaf biomass and lower relative allocation to seed biomass. The presence of neighbour affected allometric relationships only in 4 out of 24 allometic comparisons, which all appeared in low fertility treatments. Fertilizer addition increased stem&leaf biomass allocation of Monkhead and decreased root and seed biomass allocation at the same time. By contrast, stem&leaf and seed allocation of 92-46 was not changed by fertilizer addition although root allocation was decreased. Our results demonstrated that there was a trade-off between non-reproductive and reproductive allocation for wheat varieties. There was not notable tragedy of the commons in wheat varieties, although a small degree was observed in Monkhead. Moreover, the occurrence and magnitude of the tragedy was dependent on resource availability and variety resource-use strategy. Our results underlie the importance of understanding the mechanisms behind the tragedy of the commons in crop varieties with different ecological strategies, and provide insights into the role of Darwinian agriculture in global food production.