Morphological Variation and Discriminating Traits of Kersting’s Groundnut Accessions

doi:10.21203/rs.3.rs-671485/v1

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Morphological Variation and Discriminating Traits of Kersting’s Groundnut Accessions

https://doi.org/10.21203/rs.3.rs-671485/v1

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Kersting’s groundnut [Macrotyloma geocarpum (Harms) Maréchal & Baudet] (KG) is a nutritious, subterranean grain legume in West and Central Africa. Only limited information is available on the morphological traits that can discriminate accessions; without such information, appropriate breeding strategies cannot be devised. This study aimed to identify discriminating traits and assess the diversity among accessions of Kersting’s groundnut. Eighty-one KG accessions from Benin and Burkina Faso were evaluated based on 29 qualitative and quantitative traits. An experiment was conducted using an Alpha lattice design with three replications. Standardized Shannon-Weaver index (H') and descriptive statistics were calculated for qualitative traits. Pearson correlation coefficients, stepwise discriminant analysis, principal component analysis, cluster analysis and canonical discriminant analysis were conducted. Results showed that accessions varied greatly based on growth habit (H'= 0.68), flower color (H' = 0.50), seed-eye shape (H' = 0.47), and stem pigmentation (H' = 0.41). Eight quantitative traits, viz., seed width, seed thickness, number of branches per plant, petiole length, days to 50% flowering, number of seeds per pod, pod width, and pod length, were found to significantly discriminate the accessions. Accessions were grouped into three clusters based on quantitative traits. Cluster 1 had accessions with late flowering and good vegetative growth, Cluster 2 contained accessions with high germination percentage and Cluster 3 had accessions with high yield performance. Seed length varied greatly among accessions, thus indicating the potential for improving yield via seed size.

Agronomy

Descriptors

diversity

Kersting’s groundnut

Macrotyloma geocarpum

orphan crops

Table 1 Monthly average climatic data recorded on study site during experiment

Climatic parameters	August	September	October	November	December
Rainfall (mm)	82.50	183.20	138	44.20	0.00
Sunshine	141.30	160.90	201.10	250.60	243.70
Relative Humidy	80	79	78	73	63
Maximum temperature (°C)	30.30	31.20	32	33.90	35.20
Minimum temperature (°C)	22.40	22.80	23.20	23.80	23.20
Average temperature (°C)	26.40	27	27.60	28.90	29.20

Table 2 Accessions names (AN), seed color and origin of 81 Kersting’s groundnut of this study

N°	AN	Seed color	Origin
1	BUR 9	Black seed	Burkina-Faso
2	Akl 2	Cream seed	Benin
3	Agn2	Cream seed	Benin
4	Soh	Cream seed	Benin
5	Ats	Cream seed	Benin
6	Adc	Cream seed	Benin
7	Hhg	Cream seed	Benin
8	Hou	Cream seed	Benin
9	Viv	Cream seed	Benin
10	Dkp	Cream seed	Benin
11	BUR 13	Cream seed	Burkina-Faso
12	Dgo	Cream seed	Benin
13	BUR 14	Cream seed	Burkina-Faso
14	Odm 1	Cream seed	Benin
15	Aso	Cream seed	Benin
16	Sag 1	Cream seed	Benin
17	Gbo5	Cream seed	Benin
18	Gbn1	Cream seed	Benin
19	Odm 2	Cream seed	Benin
20	BUR 18	Black seed	Burkina-Faso
21	Lal3	Cream seed	Benin
22	BUR 10	Cream seed	Burkina-Faso
23	Kah 2	Cream seed	Benin
24	Gbo3	Cream seed	Benin
25	Gbo1	Cream seed	Benin
26	Itk 2	Cream seed	Benin
27	Akl 1	Cream seed	Benin
28	Kno 1	Cream seed	Benin
29	Lal2	Black seed	Benin
30	Tow1	Cream seed	Benin
31	BUR 15	Cream seed	Burkina-Faso
32	LeAd1	Cream seed	Benin
33	Itk	Cream seed	Benin
34	Kno 2	Cream seed	Benin
35	Add	Cream seed	Benin
36	Lam 1	Cream seed	Benin
37	Gbo4	Brown seed	Benin
38	Ena2	Cream seed	Benin
39	Hay 1	Cream seed	Benin
40	Agc	Cream seed	Benin

N°	AN	Seed color	Origin
41	Bin	Cream seed	Benin
42	Oua	Cream seed	Benin
43	Sag 2	Cream seed	Benin
44	Zku	Cream seed	Benin
45	BUR 7	Cream seed	Burkina-Faso
46	Ena1	Cream seed	Benin
47	Gbn 2	Cream seed	Benin
48	Itk 1	Cream seed	Benin
49	BUR 8	Black seed	Burkina-Faso
50	Agn1	Cream seed	Benin
51	Zhla3	Cream seed	Benin
52	Tos	Cream seed	Benin
53	Lgz	Cream seed	Benin
54	Zhla1	Cream seed	Benin
55	Gta1	Cream seed	Benin
56	Dog	Cream seed	Benin
57	BUR 12	Cream seed	Burkina-Faso
58	Gbo2	Cream seed	Benin
59	Kin	Cream seed	Benin
60	TON	Cream seed	Benin
61	Dov	Cream seed	Benin
62	Kem	Cream seed	Benin
63	Adj	Cream seed	Benin
64	Zhla2	Black seed	Benin
65	Ali 1	Cream seed	Benin
66	Ako	Cream seed	Benin
67	Hay 2	Cream seed	Benin
68	BUR 16	Black seed	Burkina-Faso
69	LeAd2	Black seed	Benin
70	Kah 1	Cream seed	Benin
71	Zke	Cream seed	Benin
72	Dra	Cream seed	Benin
73	Bod	Cream seed	Benin
74	Agb	Cream seed	Benin
75	Sem2	Cream seed	Benin
76	MLK	Cream seed	Benin
77	Sem1	Cream seed	Benin
78	Atc	Cream seed	Benin
79	Fol	Cream seed	Benin
80	BUR 3	Cream seed	Burkina-Faso
81	Gta3	Cream seed	Benin

Table 3. Qualitative morphological traits

Qualitative traits		Levels of qualitative traits
Growth habit		Erect
		Semi- erect
		Prostrate
Stem pigmentation		Present
Stem pigmentation		Absent
Terminal leaflet shape		Suborbicular
Terminal leaflet shape		Oblong-eliptic
Leaflet color		Green-dark
Leaflet color		Green-intermediate
Flower color		White tinged with purple
		White tinged with purple
		Greenish white
Pod shape		narrow top
Pod shape		large top
Pod color		White
		White
		White tinged with purple
Pod texture		Many grooves
Pod texture		A few groove
Easy Pod detachment		Yes
		Yes
		No
Seed shape		Elongated
Seed shape		Spherical
Seed color		Black
		Cream
		red-brown
Seed Eye shape		Triangular
Seed Eye shape		butterfly

Table 4 Phenotypic variability observed in accessions based on the calculation of the Standardized Shannon-Weaver index (H’)

Qualitative traits	Levels of variables	Accessions
		Benin			Burkina			Collection
		Frequency	Proportion	H’	Frequency	Proportion	H’	Frequency	Proportions	H’
Growth habit	erect	5	7.14	0.67	1	9.09	0.68	6	7.4	0.67
	prostrate	49	70		10	90.9		59	72.83
	semi- erect	16	22.85		0	0		16	19.75
		16	22.85		0	0		16	19.75
Stem pigmentation	Present	5	7.14	0.40	7	63.63	0.41	12	14.81	0.40
Stem pigmentation	Absent	65	92.85	0.40	4	36.36	0.41	69	85.18	0.40
Terminal leaflet form	Suborbicular	69	98.57	0.22	9	81.81	0.23	78	96.29	0.22
Terminal leaflet form	Oblong-eliptic	1	1.42	0.22	2	18.18	0.23	3	3.70	0.22
Leaflet color	Green-dark	68	97.14	0.22	10	90.9	0.23	78	96.29	0.22
Leaflet color	Green-intermediate	2	2.85	0.22	1	9.09	0.23	3	3.70	0.22
Flower color	White tinted with purple	6	8.57	0.50	3	27.27	0.50	9	11.11	0.50
	White tinted with purple	6	8.57		3	27.27		9	11.11
	Greenish white	64	91.42		8	72.72		72	88.88
Pod shape	narrow top	68	97.14	0.22	10	90.90	0.23	78	96.29	0.22
Pod shape	large top	2	2.85	0.22	1	9.09	0.23	3	3.70	0.22
Pod color	White	66	94.28	0.28	11	100	0.28	77	95.06	0.28
Pod color	White tinted withe purple	4	5.71	0.28	0	0	0.28	4	4.93	0.28
Pod texture	Many grooves	69	98.57	0.16	10	90.90	0.16	79	97.53	0.16
Pod texture	A few grooves	1	1.42	0.16	1	9.09	0.16	2	2.46	0.16
Easy Pod detachment	Yes	31	44.28	0.47	6	54.54	0.46	45	55.55	0.47
Easy Pod detachment	No	39	55.71	0.47	5	45.45	0.46	36	44.44	0.47
Seed shape	Elongated	67	95.71	0.22	11	100	0.23	78	96.29	0.22
	Spherical	3	4.28	0.22	0	0	0.23	3	3.7	0.22
Seed coat color	Black	3	4.28	0.32	4	36,36	0.33	7	8.64	0.32
	Cream	66	94.28		7	63.63		73	90.12
	Brown	1	1.42		0	0		1	1.23
Seed Eye shape	Irregular	0	0	0.47	6	54.54	0.47	6	7.4	0.47
	Triangular	2	2.85		4	36.36		6	7.4
	butterfly	68	97.14		1	9.09		69	85.18

Table 5 Minimum, maximum, mean and variation in traits of Kersting’s groundnut accessions from Benin and Burkina Faso

Descriptors†	Min	Max	Mean ± SE	CV
PG	6.98	90.7	46.37±1.11	37.42
nLe	21.29	132.9	65.75±1.27	30.05
nFlw	3	53.8	16.47±0.52	49.51
nPd	12	264.86	90.32±2.91	50.19
nBrh	2.3	20.8	9.51±0.21	34.78
nDFlw	46	56	48.83±0.12	3.93
SeWt (g)	8.14	18.64	12.92±0.1	11.56
SeL(mm)	6.91	9.69	8.21±0.03	5.06
SeW(mm)	4.74	6.42	5.68±0.02	4.63
Sth (mm)	3.33	4.92	4.26±0.01	5.37
LeL (mm)	52.71	77.96	65.75±0.26	6.19
LeW (mm)	38.03	57	48.66±0.23	7.37
PeL (mm)	81.04	208.83	143.38±1.32	14.41
PoL (mm)	6.45	17.45	12.32±0.11	13.96
PdW (mm)	3.62	9.16	7.72±0.04	8.08
nSP	1	1.73	1.3±0.01	13.67
yield (kg/ha)	239.47	9243.9	2466.89±91.54	57.84

† PG, percentage of germination; nLe, number of leaves; nFlw, number of flowers per plant; nPd, number of pod; nBrh, number of branch per plant; nDFlw, number of days at 50% flowering; SeWt, seed's weight; SeL, seed's length; SeW, seed's width; Sth, seed's thickness; LeL, leaf's length; LeW, leaf's width; PeL, petiole's length; PoL, pod's length; PdW, pod's width; nSP, number of seeds per pod.

Table 6: ANOVA of the 17 quantitative traits of kersting’s groundnut

Mean squares of the 17 quantitative traits of Macrotyloma geocarpum
	Sources of variation
Variables†	Replication	Block	Accession	Residual
	Df=2	Df=8	Df=80	Df=152
nPd	3796.67 ns	2859.94 ns	3009.66 ns	3674.19
Sth	0.72 ***	0.01 ns	0.07 ***	0.03
PdW	0.85 ns	0.42 ns	0.45 ns	0.35
nSP	0.64 ***	0.02 ns	0.03 ns	0.02
nLe	11701.59 ***	892.41 ***	271.92 ns	224.76
LeW	342.11 ***	9.12 ns	12.67 *	8.22
PG	590.31 **	456.66 ***	615.9 ***	121.36
nDFlw	1546.21 ***	44.24 ns	84.04 ***	38.82
nBrh	85.67 ***	37.52 ***	11.22 **	6.83
nFlw	20.77 ***	5.38 **	6.03 ***	2.03
SeWt	10.94 ***	1.93 ns	3.86 ***	1.20
SeL	0.57 ***	0.11 **	0.34 ***	0.08
SeW	0.28 **	0.02 ns	0.12 ***	0.04
LeL	251.01 ***	17.98 ns	19.30 **	11.92
PeL	10870.68 ***	1145.13 ***	519.38 ***	220.83
PoL	19.70 ***	2.22 ns	4.06 ***	2.11
yield	122789.82 ns	165756.29 *	174349.26 ns	145845.50

*, **, *** Significant at p < 0.05, p < 0.01; and p < 0.001, respectively. ns: not significant.

† nPd, number of pod; Sth, seed thickness; PdW, pod width; nSP, number of seeds per pod; nLe, number of leaves; LeW, leaf width; PG, percent germination; nDFlw, number of days at 50% flowering; nBrh, number of branch per plant; nFlw, number of flowers per plant; SeWt, seed weight; SeL, seed length; SeW, seed width; LeL, leaf length; PeL, petiole length; PoL, pod length.

Table 7 Correlations between agronomic traits for 81 accessions of Kersting’s groundnut

Quantitative traits†

nPd

Sth

PdW

nSP

nLe

LeW

nFlw

nBrh

nDFlw

SeWt

SeL

SeW

LeL

PeL

PoL

nPd

Sth

0.10ns

PdW

0.05ns

0.08ns

nSP

0.02ns

-0.06ns

0.01ns

nLe

0.08ns

0.02ns

0.10ns

0.11ns

LeW

0.06ns

0.02ns

0.00ns

0.03ns

0.46***

0.05ns

0.24***

0.10ns

0.08ns

0.07ns

0.12ns

nFlw

0.12ns

0.06ns

-0.04ns

0.31***

0.25***

0.21**

0.23***

nBrh

0.00ns

0.08ns

-0.06ns

-0.04ns

0.75***

0.26***

-0.01ns

-0.07ns

nDFlw

-0.17**

0-.18**

-0.08ns

-0.04ns

0.04ns

0.10ns

0.30***

0.27***

0.08ns

SeWt

0.15*

0.41***

0.14*

0.08ns

-0.06ns

0.02ns

0.29***

0.34***

-0.14*

-0.42***

SeL

0.12ns

0.22***

0.16*

0.14*

0.00ns

0.13*

0.31***

0.36***

-0.14*

-0.37***

0/.00.68***

SeW

0.17**

0.39***

0.21**

0.07ns

0.08ns

0.28***

0.35***

0.28***

-0.04ns

-0.27***

0.66***

0.80***

LeL

0.12ns

0.18**

-0.02ns

0.08ns

0.23***

0.76***

0.34***

0.43***

0.03ns

-0.26***

0.38***

0.43***

0.46***

PeL

0.10ns

0.25***

0.00ns

0.06ns

0.30***

0.58***

0.50***

0.13*

-0.41***

0.42***

0.47***

0.51***

0.77***

PoL

0.08ns

0.03ns

0.59***

0.76***

-0.02ns

0.18**

0.29***

-0.12ns

-0.19**

0.29***

0.34***

0.27***

0.12ns

yield

0.59***

0.12ns

0.05ns

0.35***

0.17**

0.07ns

0.30***

0.01ns

-0.17**

0.33***

0.23***

0.32***

0.31***

0.22***

0.38***

*, **, *** Significant at p < 0.05, p < 0.01; and p < 0.001, respectively. ns: not significant.

† Pd, number of pod; Sth, seed's thickness; PdW, pod's width; nSP, number of seeds per pod; nLe, number of leaves; LeW, leaf's width; PG, percentage of germination; nFlw, number of flowers per plant; nBrh, number of branch per plant; nDFlw, number of days at 50% flowering; SeWt, seed's weight; SeL, seed's length; SeW, seed's width; LeL, leaf's length; PeL, petiole's length; PoL, pod's length.

Table 8 Summary of the stepwise discriminant analysis identifying quantitative traits that differentiated kersting’s groundnut accessions and correlation between discriminating traits and the canonical axes (Can)

Step	Traits†	Wilks.lambda	F.statistics.overall	p.value.overall	F.statistics.diff	p.value.diff	Can1	Can2
1	PG	0.319	4.31	0.00	4.31	0.00	0.31	-0.64
2	SeL	0.11	4.00	2.39E-26	3.72	0.00	0.69	-0.08
3	Sth	0.04	3.56	1.22E-32	2.81	0.00	-0.33	-0.43
4	SeW	0.01	3.47	4.15E-41	3.23	0.00	-0.27	0.29
5	nDFlw	0.00	3.11	1.36E-42	1.92	0.00	-0.26	0.60
6	SeWt	0.00	2.84	6.08E-43	1.69	0.00	0.45	-0.49
7	nBrh	0.00	2.60	7.8E-42	1.40	0.03	0.69	-0.34

† PG, percentage of germination; SeL, seed's length; Sth, seed's thickness; SeW, seed's width; nDFlw, number of days at 50% flowering; SeWt, seed's weight; nBrh, number of branch per plant.

Table 9 Mean values and standard errors of discriminating traits in Kersting’s groundnut accessions


Traits†	Cluster 1(n=68)				Cluster 2(n=3)				Cluster 3(n=10)				F-test
Traits†	Mean¢ ±SE	CV(%)	Min	Max	Mean ±SE	CV(%)	Min	Max	Mean ±SE	CV(%)	Min	Max
PdW	7.73±0.04a	4.52	6.27	8.28	6.84±0.36b	9.06	6.22	7.46	7.94±0.06a	2.39	7.72	8.39	***
nLe	67.53±1.30a	15.92	38.11	94.3	55.73±3.19b	9.92	49.37	59.33	56.61±2.92b	16.31	40	72.10	**
LeW	49.03±0.21a	3.53	44.88	53.25	43.76±0.88b	3.48	42.34	45.37	47.57±0.88a	5.87	43.08	53.06	***
PG	44.61±1.71a	31.66	20.93	79.84	60.47±4.72a	13.51	51.94	68.22	54.11±4.25a	24.82	37.21	78.29	*
nFlw	14.72±0.39b	22.12	9.03	23.25	25.8±2.06a	13.84	21.7	28.23	25.59±1.54a	19.03	17.63	33.67	***
nBrh	10.03±0.23a	18.58	6.31	15.2	7.57±1.70ab	38.95	4.17	9.40	6.56±0.37b	17.66	5.20	8.46	***
nDFlw	49.26±0.13a	2.21	47.33	53	46.11±0.11b	0.42	46	46.33	46.7±0.27b	1.79	46	48.33	***
SeWt	12.54±0.09b	5.71	11.06	13.87	14.03±0.19a	2.34	13.83	14.41	15.18±0.29a	6.00	13.63	16.73	***
SeL	8.11±0.03b	2.60	7.61	8.67	8.3±0.12ab	2.58	8.08	8.50	8.88 ± 0.12a	4.12	8.36	9.29	***
SeW	5.64±0.02b	2.83	5.31	6.16	5.58±0.06b	1.91	5.51	5.70	6 ±0.06a	3.07	5.72	6.29	***
LeL	65.21±0.26b	3.32	59.88	70.44	65.8±0.94b	2.46	64.56	67.64	69.4±0.71a	3.23	66.10	72.82	***
PeL	140.29±1.30b	7.65	110.42	165	165.82±2.53a	2.64	160.78	168.56	157.6±3.3a	6.62	140.41	175.80	***
PoL	12.05±0.11b	7.49	9.36	14.35	11.55±0.56b	8.36	10.73	12.61	14.41±0.25a	5.54	13.07	15.75	***

*, **, *** Significant at p < 0.05, p < 0.01; and p < 0.001, respectively. ns: not significant.

† PdW, pod's width; nLe, number of leaves; LeW, leaf's width; PG, percentage of germination; nFlw, number of flowers per plant; nBrh, number of branch per plant; nDFlw, number of days at 50% flowering; SeWt, seed's weight: SeL, seed's length; SeW, seed's width; LeL, leaf's length; PeL, petiole's length; PoL, pod's length. ¢ Mean values with the same letter are not significantly different.

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Editorial decision: Major revisions
27 Oct, 2021
Reviews received at journal
10 Aug, 2021
Reviewers invited by journal
09 Aug, 2021
Editor assigned by journal
06 Jul, 2021
First submitted to journal
29 Jun, 2021

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Morphological Variation and Discriminating Traits of Kersting’s Groundnut Accessions

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