Table 3.

Analysis of R and S blackgrass phenotypes during vegetative growth at different levels of intraspecific competition.

Term	DF	F	P
Tiller number
Target phenotype	1.000	1.533	0.216
Neighbor phenotype	1.000	0.644	0.422
Growing degree days	3.863	1048.559	< 0.001***
Growing degree days × Target phenotype	1.527	3.398	0.1064
Growing degree days × Neighbor phenotype	1.000	3.075	0.0797
Tiller length
Target phenotype	1.000	34.944	< 0.001 ***
Neighbor phenotype	1.000	0.068	0.794
Growing degree days	3.964	621.536	< 0.001 ***
Growing degree days × Target phenotype	3.535	2.835	0.0151*
Growing degree days × Neighbor phenotype	1.180	2.649	0.1246
Vegetative biomass
Target phenotype	1.000	10.419	0.001**
Neighbor phenotype	1.000	9.941	0.002*
Neighbor biomass	2.330	18.97	< 0.001 ***
Neighbor biomass × Target phenotype	1.000	0.02	0.889
Neighbor biomass × Neighbor phenotype	1.000	12.57	< 0.001 ***

Tiller number and tiller length were assessed non-destructively on plants during establishment and vegetative growth. Vegetative biomass was assessed following a destructive harvest 155 days after planting. Significance of the effects of target plant phenotype, neighbor plant phenotype, and either thermal time or neighbor biomass were assessed using a generalized additive mixed modeling approach. The degrees of freedom (DF), F-statistic (F) and associated P-value (P) are shown, with asterisks denoting significance at: ^∗P ≤ 0.05, ^∗∗P ≤ 0.01, ^∗∗∗P ≤ 0.001).