No notable tragedy of the commons was found in Monkhead or in
92-46
Pot partitioning treatments allowed us to exclude confounding effects of
rooting space when testing plant responses to neighbours (Semchenko et
al. 2007). We predicted that old Monkhead would have a greater
expression of the tragedy of the commons than modern 92-46. However, our
results showed that most allometric relationships were not affected by
the presence of roots from an intra-variety neighbour (Table 3, Appendix
1, 2), which suggested stable allometric relationships in wheat crop
when confronted with root competition. However, in low fertility
treatments, old Monkhead did show some tragedy of the commons, with
slightly increased allocation to stem&leaf biomass whilst reduced seed
allocation in mesh partition compared with plastic partition (Table 3,
Appendix 1c and e). This slightly allometric plasticity due to
competition was also found in a research in Senecio vulgaris(Weiner, 2009). Anyway, as the magnitude of ‘the tragedy of the commons’
was small, they might not have ecological and agricultural significance.
However, in a recently research, both Monkhead and another modern
variety showed significant root proliferation in the presence of
neighbour’s roots and the response was much higher in Monkhead (Zhu et
al., 2019). More researches using more varieties were needed to examine
the universality of this tragedy of the commons. Moreover, old Monkhead
increased relative stem&leaf allocation in the presence of root
competition, indicating the capacity of neighbour-identity recognition
via the phytochrome system (Smith 2000) or root exudates (Dudley and
File 2007; Chen et al. 2012; Fang et al. 2013; Kong et al. 2018).