Selection of cowpea genotypes based on grain mineral and total protein content

Figures & data

Table 1. Description of cowpea genotypes tested in the study.

Genotyeps	Origin
CH14	SA
Vuli	Tanzania
Ngoji	SA
Encore	SA
Fahari	Tanzania
Glenda	SA
Pan311	SA
Mamlaka	SA
98K-5301	Nigeria
Bensogla	SA
IT845-2246	Nigeria
IT90K-59	Nigeria
IT90K-76	Nigeria
IT96D-602	Nigeria
ITOOK-1060	Nigeria
ITOOK-1217	Nigeria
TVU-14196	Nigeria
TVU11424	Nigeria
TVU12637	Nigeria
TVU13953	Nigeria
TVU6345	Nigeria
Bechuana white	SA

Table 2. Partial analysis of variance showing mean square values and significant tests for nine grain mineral and protein parameters among 22 cowpea genotypes evaluated at two locations in South Africa.

Source of variations /parameter	Replication (d.f. = 2)	Genotype (d.f. = 21)	Location (d.f. = 1)	Genotype x Location (d.f. = 21)	Error (d.f. = 86)
Cu	0.44	5.02**	12.63**	0.78	0.51
Mn	3.33	8.56**	443.61**	4.50**	1.04
Fe	18.64	988.18**	11.39	777.10**	18.52
Zn	64.88	287.85**	182.25**	232.82**	7.82
Na	567.40	68863.40**	882878.40**	25286.00**	267.10
Ca	0.00023	0.00203**	0.00848**	0.00060**	0.00020
K	2315907.00	3717561.00**	244904.00	896429.00	943370.00
Mg	91928.00	96860.00**	2186.00	66606.00**	15911.00
P	126414.00	605266.00**	62886.00	287991.00**	97027.00
Protein	54.89	15.07**	336.37**	8.75	5.59

** Significant at P < 0.001; * significant at P = 0.01; d.f.= degree of freedom; Cu = copper; Mn = manganese; Fe = iron; Zn = zinc; Na = sodium; Ca = calcium; K = potassium; Mg = magnesium; P = phosphorous.

Table 3. Mean responses for nine grain mineral elements and protein content in 22 cowpea genotypes evaluated in two locations.

	Concentration (mg kg^−^1 dry seed)
Genotype	Origin^a	Ca	Cu	Fe	K	Mg	Mn	Na	P	Pro	Zn
CH14	SA	0.07^h	5.29^fg	64.40^gh	13934^abc	1968^hg	13.08^abc	462.5^b	5633^abc	24.99^abc	41.83^cd
Vuli	Tanzania	0.12^cd	4.94^gh	68.29^efgh	12720^ijkl	2079^ef	9.96^gh	370.6^cd	5411^bcde	28.13^a	51.08^a
Ngoji	SA	0.11^de	5.29^fg	65.61^fgh	12902^ghi	1930^gi	11.47^cdefg	297.7^jk	5515^abcde	27.80^a	32.63^g
Encore	SA	0.12^cd	4.98^gh	77.57^bcd	13244^defg	1973^hg	12.12^bcde	368.6^cd	4864^fg	25.40^abc	40.62^cde
Fahari	Tanzania	0.11^de	5.16^gh	62.16^h	13808^bc	2154^bcd	11.65^bcdef	386.1^c	5123^defg	27.43^ab	35.76^efg
Glenda	SA	0.12^cd	4.46^h	72.48^cdefg	13733^bcd	2004^g	11.07^efg	325.4^ghi	5715^ab	26.51^abc	50.79^a
Pan311	SA	0.11^de	7.08^ab	80.63^b	14257^ab	2166^bc	10.48^efgh	325.5^ghi	5261^bcdef	24.34^abc	38.14d^ef
Mamlaka	SA	0.11^de	4.68^gh	70.90^defg	12107^jkl	1856^j	13.13^ab	334.0^fgh	4952^efg	27.99^a	34.83^fg
98K-5301	Nigeria	0.14^ab	5.88^de	74.98^bcde	11824^l	2093^def	11.46^cdefg	312.8^hij	4625^g	27.73^a	40.26^cde
Bensogla	SA	0.13^bc	6.93^ab	82.23^b	14452^a	2137^bcde	11.14^efg	798.1^a	5924^a	26.74^abc	35.67^efg
IT845-2246	Nigeria	0.10^ef	7.58^ab	104.36^a	12445^ijk	2130^cde	11.95^bcde	383.3^c	5277^bcdef	23.85^bc	38.98^defg
IT90K-59	Nigeria	0.16^a	6.28^b	68.27^efgh	12627^hij	1875^ij	13.30^ab	283.1^k	5417^bcde	27.86^a	40.68^cde
IT90K-76	Nigeria	0.09^fg	6.40^cd	78.25^bcd	13832^bc	2083^def	13.04^abc	256.0^l	5428^abcde	24.61^abc	48.54^a
IT96D-602	Nigeria	0.09^fg	5.60^e	71.12^defg	13041^fgh	1963^hg	9.24^h	339.2^efgh	5166^cdef	25.54^abc	35.08^fg
ITOOK-1060	Nigeria	0.10^ef	7.81^a	67.35^efgh	12048^kl	2066^efg	10.74^efgh	368.5^cd	5155^cdef	25.24^abc	42.68^cd
ITOOK-1217	Nigeria	0.11^de	6.94^b	105.94^a	13704^bcd	2243^a	10.15^fgh	355.6^def	4909^fg	23.49^c	37.32^defg
TVU-14196	Nigeria	0.08^gh	5.90^de	73.28^cdef	13702^bcd	2108^cdef	10.87^efgh	279.6^kl	5310b^cdef	26.00^abc	33.41^fg
TVU11424	Nigeria	0.11^de	5.89^de	68.44^efgh	14113^ab	2274^a	12.23^abcde	324.3^ghi	5669^abc	25.02^abc	49.72^a
TVU12637	Nigeria	0.11^de	5.01^gh	74.26^bcde	13885^bc	2094^cdef	13.78^a	361.8^cdf	5593^abcd	27.01^abc	39.69^cdef
TVU13953	Nigeria	0.12^cd	5.20^gh	79.61^bc	12530^hijk	1955^hg	11.95^bcde	349.5^defg	5311^bcdef	27.78^a	43.63^bc
TVU6345	Nigeria	0.10^ef	5.79^de	71.21^cdefg	13046^efgh	2206^ab	11.38^defg	305.6^ijk	5609^abcd	26.86^abc	38.48^def
Bechuana white	SA	0.10^ef	5.56^ef	60.64^h	13481^cdef	2043^fg	12.82^abcd	361.8^cdf	5071^efg	23.16^c	34.14^fg
Trial statistics
	Over all mean	0.11	5.85	74.64	13247	2064	11.68	361.6	5315	26.07	40.16
	Min.	0.07	4.46	60.64	11824.00	1856.00	9.24	256.00	4625.00	23.16	32.63
	Max	0.16	7.81	105.97	14452.00	2274.00	13.78	798.10	5924.00	28.13	51.08
	LSD (0.05)	0.02	1.01	6.99	1514.00	204.00	1.66	26.16	506.00	3.84	4.53
	CV (%)	9.80	10.70	5.80	7.00	6.10	8.70	4.50	5.90	9.10	6.90
	Mean Roodeplaat	0.10	6.17	74.93	13181.00	2059.00	13.51	279.60	5293.00	27.66	39.01
	Mean Syferkuil	0.12	5.55	75.06	13267.00	2068.00	9.85	443.10	5337.00	24.47	41.20

^aSA = South Africa; Min.=minimum value; Max. = maximum value; LSD = least significant difference; CV (%) = coefficient of variation in percentage; Ca = calcium; Cu = copper; Fe = iron; K = potassium; Mg = magnesium; Mn = manganese; Na = sodium; P = phosphorus; Pro = protein; Zn = zinc.

Table 4. Pair-wise correlation coefficients indicating the association of nine mineral elements and total protein content in 22 cowpea genotypes evaluated in two locations.

Characteristics	Cu	Ca	Fe	K	Mg	Mn	Na	P	Zn
Cu	–
Ca	0.01	–
Fe	0.47***	0.01	–
K	−0.03	−0.28*	0.06	–
Mg	0.36**	−0.17	0.38**	0.44***	–
Mn	−0.18	0.03	−0.24*	0.07	−0.30**	–
Na	0.19	0.16	0.12	0.33**	0.13	−0.08	–
P	−0.03	−0.09	−0.18	0.51***	0.12	0.13	0.37**	–
Zn	−0.16	0.12	−0.08	−0.01	0.12	0.04	−0.16	0.29*	–
Pro	−0.46***	0.56***	−0.42***	−0.41***	−0.41***	0.07	0.00	0.12	0.06

*** Significant at P < 0.001; ** Significant at P ≤ 0.01; * Significant at P ≤ 0.05; Pro = protein in %; Ca = calcium; Cu = copper; Fe = iron; K = potassium; Mg = magnesium; Mn = manganese; Na = sodium; P = phosphorus; Pro = protein; Zn = zinc.

Figure 1. Principal components 1 (PC1) and 2 (PC2) showing the spatial distribution of the 22 cowpea genotype based on nine seed mineral elements and protein content; Pro = protein; Ca = calcium; Cu = copper; Fe = iron; K = potassium; Mg = magnesium; Mn = manganese; Na = sodium; P = phosphorus; Pro = protein; Zn = zinc.

Table 5. Diversity index and eigenvectors within principal components involving nine mineral seed elements and total protein content in 22 cowpea genotypes evaluated in two locations.

Characteristics	Diversity index	PC1	PC2	PC3	PC4
Ca	0.89	−0.23	−0.13	0.65	0.08
Cu	0.91	0.39	−0.26	0.20	−0.08
Fe	0.89	0.38	−0.32	0.23	0.07
K	0.87	0.35	0.49	−0.10	−0.08
Mg	0.89	0.46	0.05	0.12	0.32
Mn	0.86	−0.20	0.24	−0.22	−0.16
Na	0.91	0.20	0.27	0.48	−0.48
P	0.87	0.09	0.62	0.18	0.04
Pro	0.86	−0.48	0.08	0.37	−0.05
Zn	0.89	−0.08	0.23	0.14	0.78
	Eigen value (λ)	2.64	1.87	1.40	1.18
	% total variance	26.43	18.74	14.00	11.76
	% cumulative variance	26.43	45.17	59.17	70.93

Pro = protein in %; PC = principal component; Ca = calcium; Cu = copper; Fe = iron; K = potassium; Mg = magnesium; Mn = manganese; Na = sodium; P = phosphorus; Pro = protein; Zn = zinc.

Figure 2. Dendrogram based on UPGMA depicting the genetic relationship among 22 cowpea genotypes using seed mineral elements and protein content; Pro = protein; Ca = calcium; Cu = copper; Fe = iron; K = potassium; Mg = magnesium; Mn = manganese; Na = sodium; P = phosphorus; Pro = protein; Zn = zinc.