Table 1. Photon flux density and spectral properties of nine lighting treatments.

Lighting treatments consisted of blue (B, 400–500 nm), green (G, 500–600 nm), red (R, 600–700 nm), and far-red (FR, 700–800 nm) light delivered by light-emitting diodes. The value that follows each waveband indicates its photon flux density in μmol∙m⁻²∙s⁻¹.

Lighting treatment	PPFD1 (400–700 nm)	% G2	TPFD3 (400–800 nm)	YPFD4	iPPE5	FR/(R+FR)6
B60G60R60+FR60	184.5	33.3	244.0	160.4	0.31	0.51
B60G30R90+FR60	178.9	16.6	232.2	158.8	0.39	0.40
B60G15R105+FR60	179.2	8.3	237.6	162.7	0.41	0.38
B60G6R114+FR60	178.6	3.3	234.0	163.0	0.44	0.34
B60R120+FR60	186.1	0	241.9	169.8	0.46	0.33
B60G60R60	178.8	33.3	179.7	146.4	0.81	0.02
B60G30R90	181.4	16.6	182.7	153.2	0.83	0.02
B60G15R105	180.9	8.3	182.2	155.0	0.84	0.01
B60R120	179.6	0	180.7	155.8	0.85	0.01

¹Photon flux densities (in μmol∙m⁻²∙s⁻¹) were integrated from 400 nm to 700 nm as photosynthetic photon flux density (PPFD).

²Calculated as percentage of G photon flux density relative to PPFD.

³Total photon flux densities (TPFD, in μmol∙m⁻²∙s⁻¹) were integrated from 400 nm to 800 nm.

⁴The product of TPFD and relative quantum efficiency was calculated as yield photon flux density (YPFD) based on McCree [23] and Sager et al. [24].

⁵Estimated internal phytochrome photoequilibria (iPPE) was calculated following Kusuma and Bugbee [52].

⁶FR fraction, or ratio of photon flux integral of FR (700–800 nm) to the sum of the photon flux integral of R (600–700 nm) and FR, was calculated following Kusuma and Bugbee [45].