Table 3.

Opportunity of light quality on crop speed breeding in plant factories.

Plant species	Light quality	Other experimental details	Influence on speed breeding generations		Reference
			Effects	Generations/year
Petunia (Petunia hybrida)	White light Monochromatic red light Monochromatic blue lights	70 or 150 µmol·m−2·s−1	Blue lights hasten plant flowering, whereas red light did not display flowering promotion effect.	Not available	Fukuda et al., 2016
Soybean [Glycine max (L.) Merr]	1,018 µmol·m−2·s−1 red (80%) and blue (20%) LED 1,190 µmol·m−2·s−1 full-spectrum (FS) white light is considered the control	25/18°C, day/night, 12-h photoperiod	RB LED coupled with photothermal conditions can reduce the generation cycle by 56–66 days compared with regular field conditions by 120 days.	5 generations per year	Harrison et al., 2021
Hippeastrum hybridum “Red Lion”	Red/blue light ratio of 1:9 (R10B90) and 9:1 (R90B10)	200 µmol·m−2·s−1, 14-h photoperiod	Higher blue light and low (1/10) red light intensity (R10B90) promoted early flowering and shorted flowering period.	Not available	Wang et al., 2022
Wheat (Triticum aestivum L.)	White light (W), white–green light (W:G = 4:1, W4G1), red–green light (R:G = 4:1, R4G1), red–green–blue light (R:G:B = 4:1:1, R4G1B1), red–blue lights (R:B = 3:1, R3B1; R:B = 2:1, R2B1; R:B = 1:1, R1B1; R:B = 1:6, R1B6)	360 µmol·m−2·s−1, 22-h photoperiod	Higher blue light ratio, such as R2B1 (38.1%), R1B1 (58.7%), and R1B6 (85.8%) delayed flowering time and produced fewer grains. R4G1 induced early flowering time, high yield, and excellent quality, which could be the recommended light environment for indoor wheat cultivation.	Not available	Guo et al., 2022
Tomato (Solanum lycopersicum L. cv. Micro-Tom)	Supplementary 100 µmol·m−2·s−1 red light	Supplementary red light for 12 h per day (6:00−18:00) at the onset of anthesis	Supplementary red light targeted genes that are linked to ripening and promoted the biosynthesis and signaling of ethylene, resulting in the earlier ripening of tomato fruit.	Not available	Zhang et al., 2020
Tomato (Solanum lycopersicum L. cv. Micro-Tom)	Supplementary 100 µmol·m−2·s−1 blue light	Supplementary different blue light frequencies 6 h, 8 h, 10 h, and 12 h with the same intensity at the onset of anthesis	Different frequencies of supplemental blue light accelerated flowering and promote fruit ripening approximately 3–4 days early via promoting ethylene evolution of fruits.	Not available	He et al., 2022
Tomato (Solanum lycopersicum L. cv. “Mini Chal”)	Supplement 0.4, 0.6, 0.8 W·m−2 UV-A	Basal light: R3B7 [red (R):blue (B) = 30:70], 25/18°C, day/night 50 ± 10% RH, 200 µmol·m−2·s−1, 12-h photoperiod	UV-A (0.4 W·m−2) light intensities promoted faster flowering.	Not available	Kim and Hwang, 2019
Lupin (Lupinus angustifolius L.)	R:FR ratio of 5.86, 3.42, 2.89, 2.16, and 1.14	Not available	An R:FR ratio above 3.5 might inhibit flowering while those below 3.5 might induce earlier flowering.	Not available	Croser et al., 2016
Hot pepper (Capsicum spp.)	Additional FR light intensity was set to 30, 50, 70, and 90 µmol·m−2·s−1	Basal light: white:red:blue = 3:2:1, 420 µmol·m−2·s−1, 12 h photoperiod	Supplementation low-intensity far-red light (30 µmol·m−2·s−1, R:FR = 2.1) speed up the flowering and significantly accelerated the red ripening of pepper fruit and improved seed germination rates.	4 generations per year	Liu et al., 2022
Winter canola (Brassica napus cv. “Darmorbzh”)	Additional FR 500 µmol·m−2·s−1	22-h light period; 22°C, humidity 70%	Generated visible flower buds at 92 DAG and mature seeds at approximately 125 DAG.	3 generations per year	Song et al., 2022
Spring canola (Brassica napus cv. “Westar”)			The life cycle accelerated by 12 days and mature seeds at approximately 55 DAG.	4.5 and 5.5 generations per year
Semi-winter canola (Brassica napus cv. “ZS11”)			The life cycle accelerated by 21 days and mature seeds at approximately 66 DAG.	4.5 and 5.5 generations per year
Geranium (Pelargonium × hortorum L.H.)	Supplement 10 µmol·m−2·s−1 green light during night interruption	20 ± 1°C, 60 ± 10% RH, 140 ± 20 µmol·m−2·s−1, 350 ± 50 µmol·m−2·s−1	Hasten flowering.	Not available	Park et al., 2017
Chinese kale (Brassica alboglabra)	Supplement 3 W·m−2 (FR-3), 6 W·m−2 (FR-6) far-red-light	21 ± 2°C, 55%–60% RH, CO2 concentration (400–600 µmol·mol−1) Basal light: white LED light (250 µmol·m−2·s−1 PPFD), 10-h photoperiod.	The budding rate of no-far red light treatment (control group) was only 11.1%, while that of FR-3 and FR-6 reached 30.6% and 45.8%, respectively after 45 days FR supplement. FR accelerated flowering via regulating expression of key genes in the plant circadian rhythm pathway.	Not available	Li et al., 2023
Chinese kale (Brassica alboglabra)	Supplement 40 µmol·m−2·s−1 UVA	Basal light: white 250 µmol·m−2·s−1, 12-h photoperiod UVA exposure for 6 h/d	Induced faster flowering of Chinese kale than no-UVA treatment.	Not available	Gao et al., 2022
Petunia (Petunia × hybrida)	Supplement green light intensity 0, 2, 13, or 25 µmol·m−2·s−1	Not available	Accelerated flowering of all long-day plants (Petunia, Ageratum, Snapdragon, and Arabidopsis) and delayed flowering of all short-day plants (Chrysanthemum and Marigold).	Not available	Meng and Runkle, 2019
Ageratum (Ageratum houstonianum)
Snapdragon (Antirrhinum majus)
Arabidopsis (Arabidopsis thaliana)
Chrysanthemum (Chrysanthemum morifolium)
Marigold (Tagetes erecta)