Agronomic performance of Populus deltoides trees engineered for biofuel production

Table 2 Phenotypes measured in the field trial

Phenotypes	Units	Mean	SD^a	r ^{2 b}	P-value^c
Growth and yield
Total height	cm	207	16	0.558	2.23E−12
Internode length	cm	14.8	1.8	0.373	6.92E−03
Height growth	cm	130	17	0.317	3.28E−06
Quadratic mean diameter	mm	23.2	2.9	0.602	5.86E−05
Volume index	m³	0.362	0.108	0.670	1.87E−05
Crown architecture
Height to first branch	cm	117	15	0.297	5.03E−06
Number of branches	Counts	13.3	4.0	0.286	6.85E−09
Stem sinuosity	Score: 0–4	1.21	0.86	0.028	3.89E−02
Stem length-height ratio	NA	0.988	0.019	0.187	4.70E−02
Apical index	NA	1.40	0.13	0.257	1.65E−02
Trunk section eccentricity	NA	0.215	0.097	0.069	6.00E−01
Vegetative phenology
Bud set	Score: 1–6	3.04	0.17	0.007	1.39E−74
Bud flush	Score: 1–6	5.18	0.35	0.189	2.55E−09
Stress response
Frost damage	Score: 0–3	1.93	0.26	0.385	1.50E−01
Melampsora severity	Score: 0–4	2.99	0.12	0.064	3.51E−01
Overall herbivory	Score: 1–10	2.41	1.69	0.100	8.56E−01
Twig borer incidence	Counts	2.79	1.86	0.096	6.18E−01

NA not applicable for dimensionless trait
^aThe standard deviation (SD) of observed values
^bCoefficient of determination, r ², between the observed values and the values predicted by the TPS models, an indicator of the degree of spatial-dependent variation in the trait
^cSignificance level, P value, of the one-way ANOVAs for all lines (k = 37; including the seven empty-vector control lines and the wild type)

ISSN: 2731-3654