Evaluation of a suitable seed processing method for increased production of edible nightshade (Solanum scabrum) leafy vegetable

Figures & data

Figure 1. Experimental site map (Muthara location), Meru County.

Table 1. Field experiment plots' layout

A	BLOCK 1	BLOCK 2
1	WSP1	DFP1
2	DSP1	DSP2
3	DFP2	WFP2
4	WFP2	WSP1
5	DFP1	DFP2
6	WSP2	WFP1
7	DSP2	WSP2
8	WFP1	DSP1
B	BLOCK 4	BLOCK 5
1	DFP4	WFP3
2	WSP4	DFP4
3	DSP3	WSP4
4	WSP3	DSP3
5	WFP3	DFP3
6	DSP4	WSP3
7	DFP3	WFP4
8	WFP4	DSP4

Key

1–4 Replicate numbers

WSP-Wet Seed Processing

DSP-Dry Seed Processing

WFP-Wet Fermentation Processing

DFP-Dry Fermentation Processing

Figure 2. Seed processing method preference in each Agroecological zone.

Plate 1. Dry processed seeds.

Plate 2. Wet-processed seeds.

Plate 3. Dry fermentation processed seeds.

Plate 4. Wet fermentation processed seeds.

Table 2. Farm-saved seed moisture content, germination and growth tests for seeds processed using different seed processing methods under laboratory conditions

Seed processing	MC	GP	GI	T50	SE	SL (cm)	SVI
Wet seed processing	11.1^c	81.4^a	13.2^a	3.3^a	83.6^a	3.6^a	293.0^a
Dry seed processing	8.6^a	80.3^a	11.2^a	4.1^c	82.4^a	3.8^a	305.1^a
Wet seed fermentation	9.2^a	89.2^c	18.3^c	3.2^a	91.2^c	3.9^b	347.9^b
Dry seed fermentation	10.2^b	84.2^b	14.3^b	3.7^b	86.7^b	3.6^a	303.1^a
Lsd (p ≤ 0.05)	0.9	2.3	2.6	0.24	1.8	0.2	44.3
CV (%)	13.4	24.5	19.3	19.4	31.6	8.8	12.6
Wet seed processing	9.2^b	82.1^a	12.0^a	3.1^a	88.3^b	3.5^a	287.4^a
Dry seed processing	7.4^a	82.4^a	10.5^a	4.2^c	86.1^a	3.7^a	304.9^a
Wet seed fermentation	7.9^a	88.8^b	18.1^c	3.1^a	93.5^c	4.1^b	364.1^b
Dry seed fermentation	8.2^a	81.2^a	14.6^b	3.9^b	87.2^a	3.9^b	316.7^a
^1Lsd (p ≤ 0.05)	0.8	2.5	2.5	0.26	1.7	0.3	33.8
^2CV (%)	16.2	29.1	20.1	23.4	22.1	8.3	13.8

¹Least significance difference

²Coefficient of variation. Means followed by the same letter(s) within columns are not significantly different (p ≤ 0.05) while those followed by the different letter (s) within columns are significantly different; means are separated by LSD (p ≤ 0.05).

MC—Moisture content, GP—Germination percentage, GI—germination index, T50-time to 50% germination, SE—seedling emergence, SL—seedling length and SVI—Seedling vigor index.

Figure 3. Stand count, plant height (cm) and days to 1^st flower for seeds processed by different methods.

Figure 4. Branches/plant, fruits/plant and seed yields (kgha⁻¹) for seeds processed by different methods.

Table 3. Seed quality parameters for different seed processing methods

Seed processing method	Pure seed	Other crop seeds	Inert matter	Discolored seeds	Shriveled seed	Insect damaged
Wet seed processing	87.5^ab	2.8^b	5.0^b	2.7^b	1.4^b	0.6^c
Dry seed processing	76.4^b	4.3^a	6.3^b	6.9^a	4^a	2.1^b
Wet seed fermentation	96.3^a	0.5^c	1.2^c	1.2^b	0.8^c	0.0^c
Dry seed fermentation	72.0^b	4.2^a	10.3^a	5.5^a	4.2^a	3.8^a
^1Lsd (p ≤ 0.05)	12.6	1.2	2.8	2.4	1.3	1.2
^2Cv%	24.3	19.3	14.2	22.1	17.4	32.1

¹Least significant differences and ²coefficient of variation. Values are the means, each having three replicates. Means followed by the same letter(s) within columns are not significantly different (p ≤ 0.05) while those followed by the different letter (s) within columns are significantly different; means are separated by LSD (p ≤ 0.05).

Table 4. Seed moisture content, germination and growth tests for seeds processed using different seed processing methods under laboratory conditions

Seed processing	MC	GP	GI	T50	SL (cm)	SVI
Wet seed processing	10.2^a	84.2^b	14.2^b	3.6^b	3.9^b	328.4^b
Dry seed processing	8.4^b	84.1^b	13.8^b	4.1^a	3.8^b	319.6^b
Wet seed fermentation	9.6^a	97.2^a	20.1^a	3.4^b	4.2^a	408.2^a
Dry seed fermentation	8.1^b	92.1^a	18.2^a	4.2^a	3.7^b	340.8^b
Lsd (p ≤ 0.05)	1.2	5.4	3.8	0.24	0.2	52.3
CV (%)	23.1	31.2	19.2	27.2	8.8	31.7
Wet seed processing	10.1^a	84.1^b	15.0^b	3.4^b	4.3^a	361.6^bc
Dry seed processing	8.3^b	86.2^b	17.5^ab	4.3^a	3.6^c	310.3^c
Wet seed fermentation	9.6^a	95.4^b	20.2^a	3.6^b	4.6^a	438.8^a
Dry seed fermentation	8.4^b	93.5^a	19.3^a	4.1^a	4.1^b	383.4^b
^1Lsd (p ≤ 0.05)	1.1	6.2	3.2	0.32	0.4	54.2
^2CV (%)	31.2	19.6	28.1	23.4	14.1	23.6

¹Least significant difference.

²Coefficient of variation. Means followed by the same letter(s) within columns are not significantly different (p ≤ 0.05), while those followed by the different letter (s) within columns are significantly different; means are separated by LSD (p ≤ 0.05). MC: Moisture content, GP: Germination percentage, GI: Germination Index, T50: Time to 50% germination, SL: Seedling length and SVI: Seedling Vigor Index.

Figure 5. Principal component analysis (PCA) of different germination parameters under different treatment methods.

Table 5. Correlation between different germination parameters with different seed processing methods

Characters	SP (%)	GP (%)	GI	SVI	F/P	Y/HA
SP (%)	1	0.922**	0.855**	0.811*	0.125	0.828**
GP (%)	0.666**	1	0.635	0.756*	0.526	0.766*
GI	0.433	0.867**	1	0.723*	0.245	0.568
SVI	0.913**	0.898**	0.766*	1	0.332	0.968**
F/P	0.322	0.831*	0.327	0.327	1	0.748
Y/HA	0.922**	0.913**	0.388	0.782*	0.234	1

SP: Seed Purity, GP: Germination percentage, GI: Germination Index, SVI: Seedling Vigor Index, F/Fruits/Plant and Y/HA: Yields per hectare. *, ** Significant correlation at p ≤ 0.05 and p ≤ 0.01, respectively.