Plant architecture, plasticity, and adaptation strategies of two oat genotypes under different competition intensities.
BACKGROUND
The hypothesis that positive and negative interactions account for adaptive strategies was tested in a controlled study with two oat (Avena sativa) genotypes: 'Manotick' with erect leaves and 'Oa1316-1' with prostrate leaves. An increasing competition pattern was designed by varying the number of seeds planted in each container and the space between containers, thus creating different planting density regimes (i.e. alternative and solid treatments).


RESULTS
Total biomass of individual plants tended to decrease exponentially with increasing density in both genotypes. Under high density stress, Manotick allocated more biomass to the roots and produced 50% more tillers, leading to more non-productive tillers and lower harvest index in the alternative than in the solid treatment. In contrast, Oa1316-1 allocated more biomass to panicles and stems, and less to the roots, with fewer tillers.


CONCLUSIONS
With increasing density and strengthening intraspecific competition, Manotick reduced aboveground biomass allocation, leading to lower yield, while Oa1316-1 decreased allocation to the roots, but increased allocation to the panicles under an increasingly competitive environment. These adjustments were mechanically derived from negative and positive interactions, ensuring greater yield in the prostrate type. Our findings provided a novel rationale for a planting strategy based on plant type selections.
Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.|Agriculture and Agri-Food Canada, Science and Technology Branch, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, Ontario, Canada K1A 0C6.
Pu-Fang
PF
Li
Agriculture and Agri-Food Canada, Science and Technology Branch, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, Ontario, Canada K1A 0C6.
Bao-Luo
BL
Ma
Agriculture and Agri-Food Canada, Science and Technology Branch, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, Ontario, Canada K1A 0C6.
Weikai
W
Yan
Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
Zheng-Guo
ZG
Cheng
Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
Feng-Min
FM
Li
Key Laboratory of Grassland Agro-ecosystems, Institute of Arid Agroecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
You-Cai
YC
Xiong
D000222:Adaptation, Physiological / Q000235:genetics; D000383:Agriculture / Q000379:methods*; D018554:Avena / Q000235:genetics* / Q000254:growth & development*; D018533:Biomass; D005838:Genotype; D018515:Plant Leaves / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology; D018517:Plant Roots / Q000254:growth & development
adaptation strategy; biomass allocation; oat (Avena sativa); trade-off mechanism