Estimation of grain quality of rice (Oryza sativa L.) by UAV-acquired vegetation index and climate factors

Figures & data

Table 1. Transplanting and heading dates, N levels, transplanting density and number of plots per planting date in Koshihikari and Ishikawa 65.

		Date of transplant	Heading date	Number of plots	Levels of N (g m^−2)	Levels of transplanting density
Koshihikari	2019	13 May	1–3 Aug.	12	4 (0.0–9.0)	1 (18.5)
	2020–1	28 April	31 Jul.-2 Aug.	6	3 (3.5–5.0)	1 (18.5)
	2020–2	10 May	6–8 Aug.	12	4 (0.0–9.0)	1 (18.5)
	2021–1	30 April	1–3 Aug.	6	3 (3.5–5.0)	1 (18.5)
	2021–2	13 May	4–6 Aug.	10	5 (0.0–9.5)	1 (18.5)
	2022	4 May	1–3 Aug.	10	5 (0.0–9.5)	1 (18.5)
Ishikawa 65	2019–1	10 May	5–8 Aug.	12	3 (5.6–14.6)	2 (17.4 & 22.2)
	2019–2	24 May	12–14 Aug.	18	2 (3.0 & 14.0)	2 (11.1 & 22.2)
	2020–1	10 May	11–15 Aug.	12	2 (5.6 & 14.6)	2 (17.4 & 22.2)
	2020–2	24 May	18–20 Aug.	12	2 (3.0 & 14.0)	2 (11.1 & 22.2)
	2021	7 May	8–10 Aug.	12	3 (5.6–14.6)	2 (11.1 & 22.2)
	2022	13 May	6–8 Aug.	18	3 (5.6–14.6)	2 (11.1 & 22.2)

Figure 1. Percentages of BBWG, MWG, OTG, and perfect grains averaged over plots in each cropping in Koshihikari and Ishikawa 65.

Figure 2. Relations between CIG₀, T ₊₂₀, or R₋₂₀ and BBWG in Koshihikari and Ishikawa 65.

Significant at **0.01 and ***0.001.

Figure 3. Relations between CIG₀, T ₊₂₀, or R₋₂₀ and MWG in Koshihikari and Ishikawa 65.

Significant at × 0.05 and ***0.001.

Figure 4. Relations between CIG₀, T ₊₂₀, or R₋₂₀ and OTG in Koshihikari and Ishikawa 65.

Significant at ***0.001.

Figure 5. Relations between CIG₀, T ₊₂₀, or R₋₂₀ and GPC in Koshihikari and Ishikawa 65.

Significant at ***0.001.

Table 2. Multiple regression analysis with BBWG, MWG, OTG, and GPC as dependent variables and CIG₀, R₋₂₀, and T ₊₂₀ are independent variables.

		Adjusted R^2		Intercept	Regression coefficient						Partial correlation coefficient			VIF
					CIG0		R−20		T +20		CIG0	R−20	T +20	CIG0	R−20	T +20
Koshihikari	BBWG	0.762	***	−271.670	−3.201	***	0.077	***	10.052	***	−0.68	0.53	0.79	1.02	3.15	3.16
	MWG	0.396	***	−7.170	0.639	*	0.028	***			0.33	0.61		1.00	1.00
	GPC	0.639	***	3.692	0.362	***					0.81			1.00
Ishikawa 65	BBWG	0.584	***	44.632	−1.072	***	−0.068	***			−0.38	−0.76		1.02	1.02
		0.455	***	−71.537	−0.943	***			3.168	***	−0.30		0.67	1.01		1.01
	MWG	0.292	***	4.090	0.905	***	−0.012	**			0.47	−0.31		1.02	1.02
	OTG	0.566	***	−17.570	1.534	***	0.034	***			0.66	0.66		1.02	1.02
		0.574	***	46.208	1.485	***			−1.794	***	0.65		−0.66	1.01		1.01
	GPC	0.497	***	3.356	0.366	***					0.71			1.00

Significant at × 0.05, **0.01 and ***0.001.

Figure 6. Relations between observed and estimated BBWG, MWG, OTG, and GPC in Koshihikari and Ishikawa 65.

Figure 7. Estimated BBWG, MWG, OTG, and GPC at the mean T ₊₂₀ and R_-20 in the last 10 years.

The shaded area indicates both BBWG + MWG < 25% and GPC < 6.5% is achieved in Koshihikari and both BBWG + MWG + OTG < 25% and GPC < 6.5% in Ishikawa 65.

Figure 8. Relations between CIG₀ and grain yield in Koshihikari and Ishikawa 65.

Significant at ***0.001.