. 2016 Mar 29;7:274. doi: 10.3389/fpls.2016.00274

Table 3.

Stepwise regression model of optimized nutrient media for different measured in vitro factors of OHF pear rootstock.

Measured factor	Variable^a	Parameter estimation	Standard error
PROLIFERATION
	Intercept¹	3.55	0.19
	NH $_{4}^{+}$	–0.08	0.00
	Mg²⁺	0.99	0.07
	SO $_{4}^{2 -}$	–0.16	0.05
R²		0.39
RMSE		1.02
MBE		0.13
SL
	Intercept	1.16	0.26
	NO $_{3}^{-}$	0.35	0.05
	NH $_{4}^{+}$	–0.28	0.05
	Ca²⁺	0.07	0.03
	K⁺	–0.33	0.05
	Mg²⁺	–0.90	0.06
	PO $_{4}^{2 -}$	0.35	0.08
	SO $_{4}^{2 -}$	0.35	0.05
R²		0.44
RMSE		0.79
MBE		–0.04
STN
	Intercept	–24.18	2.35
	NO $_{3}^{-}$	0.78	0.05
	K⁺	0.71	0.08
	Mg²⁺	–14.53	0.86
	SO $_{4}^{2 -}$	5.18	0.52
	Cl⁻	–3.01	0.31
R²		0.67
RMSE		10.22
MBE		0.05
CHL
	Intercept	–78.05	14.97
	NO $_{3}^{-}$	313.32	64.45
	NH $_{4}^{+}$	–313.17	64.46
	Ca²⁺	–622.62	128.76
	K⁺	–312.71	64.46
	Mg²⁺	–318.56	64.46
	PO $_{4}^{2 -}$	312.10	64.38
	SO $_{4}^{2 -}$	314.43	64.44
	Cl⁻	621.96	128.75
R²		0.72
RMSE		3.53
MBE		0.39
VITRI
	Intercept	–4.64	0.97
	NO $_{3}^{-}$	0.27	0.01
	Mg²⁺	–4.85	0.31
	PO $_{4}^{2 -}$	1.43	0.30
	SO $_{4}^{2 -}$	2.83	0.19
	Cl⁻	–1.50	0.11
R²		0.54
RMSE		3.67
MBE		–0.15

Significant variable entered in the model. All variables left in the model are significant (p < 0.05).