Phenotypic techniques and applications in fruit trees: a review

Table 2 The applications of digital photography in the study of fruit tree phenotypes

Applications	Species	Scale	Devices	Detected parameters	Evaluation parameters		Advantages	Limitations	References
Applications	Species	Scale	Devices	Detected parameters	Indices	Performance evaluation	Advantages	Limitations	References
Architecture parameters	Apple orchard	T	Nikon FC-E8 fisheye lens	LAI; PAI			Low cost; high accuracy; especially suitable for the determination of LAI	Susceptible to uneven light and overlapping blades	[55]
		T	CID CI-110 fisheye lens	LAI		Error = 13%			[56]
		T	Digimax A503 Samsung	LAI		R² = 0.85; RMSE = 0.22			[61]
	Almond orchard	T	Nikon FC-E8 fisheye lens	LAI	NDVI	R² = 0.88			[57]
	Almond orchard	T	Nikon FC-E8 fisheye lens	LAI	NDWI	R² = 0.91			[57]
	Vineyard	T	Digimax A503 Samsung	LAI		R² = 0.97; RMSE = 11.5%			[62]
	Vineyard	T	Canon EOS 60D	LA		R² = 0.93; RMSE = 3.0%			[63]
	Citrus orchard	T	Canon EOS 6D	C_v					[64]
Biochemical parameters	Mango	F	Kodak D5100	Chl-a	(NDVI − VARI)/(NDVI + VARI)	R² = 0.71	RGB images can reflect colour information well	The evaluation accuracy is not high enough	[45]
				Chl-t	(NDVI − VARI)/(NDVI + VARI)	R² = 0.71
				Chl-b	(R − B)/(R + B)	R² = 0.57
				Carotenoids		R² = 0.53
				TSS		R² = 0.57
				TA		R² = 0.59

Note: In the “scale” column of the table, the fruit tree objects are divided into individual trees (T) and fruits (F)

ISSN: 1746-4811