Performance of sugarcane genotypes across seven environments
Table (3 and 4) shown the performance of sugarcane genotypes across seven environments, that the genotypes varied significantly in cane and sugar yield, respectively. G2 (G.2016-168 ) produced the higher value of cane yield of 68.04 and 67.68 ton.acre-1,in E1 and E2 which was 8.9% and 6.2% higher than the check variety GT. 54-9 (Table 5). Additionally, G.2016-168 produced a sugar yield of 8.45 and 8.04 ton.acre-1 , in E1 and E2, respectively, which was 30% and 20.5% higher than the check variety GT. 54-9.
Table3 : Mean performance of cane yield of the studied sugarcane genotypes across seven environment
|
Genotypes
|
E1
|
E2
|
E3
|
E4
|
E5
|
E6
|
E7
|
F-150 (G1)
|
57.18g
|
71.47b
|
54.53de
|
49.95fg
|
52.00cd
|
38.55gh
|
43.42g
|
G.2016-168 (G2)
|
68.04c
|
67.68c
|
48.66g
|
54.44c
|
45.80ef
|
44.12e
|
45.20f
|
G.2016-158 (G3)
|
58.80f
|
86.73a
|
31.44k
|
52.14de
|
51.00d
|
47.62d
|
48.50de
|
G.2016-74 (G4)
|
39.93j
|
70.55b
|
43.67i
|
44.00j
|
45.00fg
|
60.20a
|
47.50e
|
G.2016-62 (G5)
|
74.36a
|
62.92d
|
27.84l
|
61.89a
|
51.80cd
|
37.50h
|
40.00h
|
G.2016-99 (G6)
|
71.68b
|
63.04d
|
39.75j
|
48.00h
|
50.60d
|
52.90c
|
50.00cd
|
G.2016-129 (G7)
|
66.78cd
|
60.72e
|
55.50d
|
57.84b
|
51.40d
|
52.10c
|
51.00bc
|
G.2016-128 (G8)
|
65.76d
|
48.00i
|
53.62ef
|
45.00ij
|
46.80e
|
44.00e
|
43.00g
|
G.2016-95 (G9)
|
58.18fg
|
58.50f
|
52.27f
|
42.00k
|
43.80g
|
39.10g
|
40.00h
|
G.2009-11 (G10)
|
55.58h
|
50.70h
|
54.54de
|
45.98i
|
54.60b
|
61.53a
|
58.00a
|
K.81113 (G11)
|
38.00k
|
36.74k
|
54.42de
|
43.50jk
|
44.40fg
|
47.86d
|
48.50de
|
G.99-80 (G12)
|
44.17i
|
43.78j
|
75.23b
|
49.20gh
|
54.60b
|
41.00f
|
30.02i
|
G.2005-47 (G13)
|
57.25g
|
50.50h
|
67.44c
|
51.16ef
|
58.00a
|
54.82b
|
52.00b
|
G.2000-5 (G14)
|
72.22b
|
54.46g
|
45.29h
|
52.00de
|
53.00c
|
53.00c
|
42.50g
|
G.T.54-9 (G15)
|
62.50e
|
63.70d
|
80.27a
|
53.05cd
|
55.40b
|
55.78b
|
44.98f
|
Table 4: Mean performance of sugar yield of the studied sugarcane genotypes across seven environment
|
Genotypes
|
E1
|
E2
|
E3
|
E4
|
E5
|
E6
|
E7
|
F-150 (G1)
|
6.71ef
|
8.55a
|
6.28cd
|
6.73abc
|
6.86a
|
4.95g
|
5.71bcd
|
G.2016-168 (G2)
|
8.45a
|
8.04a
|
6.51bcd
|
6.81ab
|
5.71bcd
|
5.65ef
|
5.81abcd
|
G.2016-158 (G3)
|
6.18f
|
8.62a
|
4.13e
|
6.19cd
|
5.75bcd
|
6.21cde
|
5.95abc
|
G.2016-74 (G4)
|
3.65h
|
7.27b
|
4.05e
|
5.71de
|
4.72d
|
7.66a
|
6.34a
|
G.2016-62 (G5)
|
6.93cdef
|
5.34de
|
3.86e
|
6.07d
|
6.29abc
|
3.69h
|
4.11g
|
G.2016-99 (G6)
|
7.81ab
|
6.97b
|
4.60e
|
5.91d
|
6.15abc
|
5.84def
|
5.61cde
|
G.2016-129 (G7)
|
7.64abcd
|
7.12b
|
7.75b
|
6.76abc
|
6.11abc
|
6.32bcd
|
6.22ab
|
G.2016-128 (G8)
|
7.49bcde
|
5.97c
|
6.32bcd
|
5.31ef
|
5.68bcd
|
5.37fg
|
5.32def
|
G.2016-95 (G9)
|
7.74abc
|
7.22b
|
6.76bc
|
5.21ef
|
5.33cd
|
4.88g
|
5.11ef
|
G.2009-11 (G10)
|
6.61f
|
4.77e
|
5.21de
|
4.79f
|
5.22cd
|
6.59bc
|
6.23ab
|
K.81113 (G11)
|
4.08h
|
4.04f
|
6.43bcd
|
5.31ef
|
4.95d
|
5.92def
|
6.01abc
|
G.99-80 (G12)
|
5.31g
|
4.77e
|
9.66a
|
6.98a
|
6.53ab
|
4.96g
|
3.94g
|
G.2005-47 (G13)
|
6.87def
|
5.84cd
|
7.50bc
|
6.23bcd
|
7.05a
|
6.46bcd
|
6.21ab
|
G.2000-5 (G14)
|
8.01ab
|
5.18e
|
4.47e
|
5.91d
|
6.71ab
|
5.91def
|
4.81f
|
G.T.54-9 (G15)
|
6.51f
|
6.67b
|
9.60a
|
6.79ab
|
5.23cd
|
6.98b
|
5.48cde
|
Additive main effect and multiplicative interaction (AMMI)
The combined analysis of variance for cane and sugar yield showed that genotypes (G) contributed 12% and 17.8% respectively to the total sum of squares while environments (E) contributed 21.4% and 8.4% respectively. GEI contributed to 66.3% and 73.4% to the total sum of squares of cane and sugar yield respectively (Table 5). The first and second interaction principal component axis (IPCA1 and IPCA2) were highly significant and accounted for 56.11and 20.81% of the sums of squares for cane yield and 44.06 and 28.52% for sugar yield of the total GEI variation, respectively. The GEI was highly significant implying differential response of genotypes to environments (20).
Table 5. Additive main effects and multiplicative interaction (AMMI) analysis of variance for cane and sugar yield of studied sugarcane genotypes across seven environments
|
Source
|
d.f.
|
M.s.
|
Explained%
|
Cane yield
|
Sugar yield
|
Cane yield
|
Sugar yield
|
Cane yield
|
Sugar yield
|
Genotypes
|
14
|
14
|
298.9**
|
5.867**
|
12.11
|
17.18
|
Environments
|
6
|
6
|
1234.1**
|
6.686**
|
21.43
|
8.39
|
Block
|
14
|
14
|
4.1**
|
0.63**
|
0.16
|
1.84
|
Interactions
|
84
|
84
|
272.6**
|
4.015**
|
66.29
|
73.41
|
IPCA 1
|
19
|
19
|
676.3**
|
7.823**
|
56.11
|
44.06
|
IPCA 2
|
17
|
17
|
280.4**
|
5.661**
|
20.81
|
28.52
|
Residuals
|
48
|
48
|
110.1**
|
1.926**
|
23.08
|
27.39
|
An ideal environment (21) and genotype are the one which is on the central circle (Fig.1 and 2). Thus, Fig. 1 and 2 shows the comparison plot for clones, and a model clone is one which is near or at the middle of the concentric circle. Based on this assumption, G7 (G2016-129) was the most ideal clone, with high mean cane , sugar yields and high stability.
The analysis AMMI stability values (ASV) exposed that some sugarcane genotypes have high adaptation; though, most of genotypes have specific adaptability (Table 6?). The ASV values showed variations in cane yield stability among the fifteen sugarcane clones (Table 6). According to (18), a stable cultivar is defined as one with AMMI stability values (ASV) value close to zero. The larger the ASV value, either negative or positive, the more specifically adapted a genotype was to certain environments. A smaller ASV value indicated a more stable genotype across environments (17). Consequently, the genotypes G.2016-95 and F-150 with ASV of 0.54 and 1.48, respectively, in addition to G.2016-129 with ASV of 1.64 were the most stable, while the genotypes such as G.99-80, G.2016-158 and G.2016-62 were the least stable (Table 6). As well as ASV exposed variations in sugar yield stability among the 15 sugarcane genotypes. On the other hand the genotypes G.2009-11, G.2016-128 and G.2016-129 were the most stable for sugar yield.
Table 6. Means, IPCA scores and AMMI stability value (ASV) of 15 Genotypes for cane and sugar yield
|
Cane yield
|
Genotype
|
Mean
|
IPCAg1
|
IPCAg2
|
ASV
|
F-150 (G1)
|
52.44
|
0.55
|
-0.07
|
1.48
|
G.2016-168 (G2)
|
53.42
|
1.37
|
0.83
|
3.77
|
G.2016-158 (G3)
|
53.75
|
3.71
|
-2.12
|
10.19
|
G.2016-74 (G4)
|
50.12
|
0.51
|
-4.17
|
4.40
|
G.2016-62 (G5)
|
50.90
|
3.43
|
2.38
|
9.53
|
G.2016-99 (G6)
|
53.71
|
1.82
|
0.26
|
4.91
|
G.2016-129 (G7)
|
55.76
|
0.59
|
0.44
|
1.64
|
G.2016-128 (G8)
|
49.45
|
-0.58
|
1.62
|
2.26
|
G.2016-95 (G9)
|
47.73
|
-0.05
|
0.52
|
0.54
|
G.2009-11 (G10)
|
54.42
|
-1.20
|
-1.54
|
3.58
|
K.81113 (G11)
|
44.77
|
-2.55
|
-1.45
|
7.01
|
G.99-80 (G12)
|
48.29
|
-3.82
|
1.08
|
10.32
|
G.2005-47 (G13)
|
55.88
|
-2.26
|
-0.05
|
6.08
|
G.2000-5 (G14)
|
53.21
|
0.78
|
1.50
|
2.58
|
G.T.54-9 (G15)
|
59.81
|
-2.29
|
0.76
|
6.21
|
Sugar yield
|
F-150 (G1)
|
6.54
|
0.31
|
0.18
|
0.56
|
G.2016-168 (G2)
|
6.71
|
0.30
|
0.50
|
0.72
|
G.2016-158 (G3)
|
6.10
|
0.92
|
-0.44
|
1.66
|
G.2016-74 (G4)
|
5.72
|
0.50
|
-1.67
|
1.89
|
G.2016-62 (G5)
|
5.03
|
0.87
|
0.65
|
1.64
|
G.2016-99 (G6)
|
6.12
|
0.70
|
0.21
|
1.23
|
G.2016-129 (G7)
|
6.84
|
-0.28
|
0.15
|
0.51
|
G.2016-128 (G8)
|
5.97
|
-0.01
|
0.47
|
0.47
|
G.2016-95 (G9)
|
6.03
|
-0.01
|
0.57
|
0.57
|
G.2009-11 (G10)
|
5.62
|
0.07
|
-0.39
|
0.41
|
K.81113 (G11)
|
5.24
|
-0.70
|
-0.86
|
1.49
|
G.99-80 (G12)
|
6.02
|
-1.56
|
0.37
|
2.72
|
G.2005-47 (G13)
|
6.59
|
-0.43
|
-0.05
|
0.74
|
G.2000-5 (G14)
|
5.85
|
0.48
|
0.46
|
0.96
|
G.T.54-9 (G15)
|
6.77
|
-1.17
|
-0.13
|
2.03
|
Stability measurements and cultivar superiority index
The sugarcane genotypes were ranked according to their superiority indices, cane and sugar yield and stability measures over the seven environments (Tables 7 &8). Sugarcane genotypes exhibited variances in their means superiority and stability values. Cultivar superiority index varied from 69 to 378.10. GT54-9 showed the highest mean cane yield, and was regarded as greatest superior and stable genotype with a superiority index of 69 and stability values of 123.7. By contrast, G.2016-129 genotype recorded the highest mean sugar yield, and was regarded as maximum superior and stable genotype with a superiority index of 0.66 and stability values of 0.46. GT54-9 ranked second in terms of superiority index in sugar yield however its cane yield was the highest mean.
Table 7. Cane yield, cultivar superiority index and mean rankings of the15 selected genotypes
|
|
Code
|
Genotype
|
Cane yield mean (t/acre)
|
Cultivar Superiority index
|
Mean ranks
|
Static stability
|
G15
|
G.T.54-9
|
59.40
|
69.00
|
4.43
|
123.7
|
G7
|
G.2016-129
|
56.50
|
110.70
|
5.29
|
33.7
|
G13
|
G.2005-47
|
55.90
|
140.90
|
5.57
|
34.5
|
G2
|
G.2016-168
|
53.43
|
148.50
|
7.29
|
108.7
|
G1
|
F-150
|
52.46
|
151.50
|
8.00
|
111.6
|
G6
|
G.2016-99
|
53.76
|
184.40
|
7.43
|
109
|
G10
|
G.2009-11
|
54.42
|
185.10
|
6.43
|
25
|
G14
|
G.2000-5
|
53.23
|
193.30
|
7.29
|
90.1
|
G3
|
G.2016-158
|
53.76
|
219.00
|
7.29
|
280.7
|
G8
|
G.2016-128
|
49.47
|
230.80
|
10.29
|
63.9
|
G9
|
G.2016-95
|
47.70
|
234.30
|
11.93
|
71.1
|
G4
|
G.2016-74
|
50.14
|
243.70
|
9.14
|
122.6
|
G12
|
G.99-80
|
48.34
|
297.10
|
9.86
|
196.4
|
G5
|
G.2016-62
|
50.99
|
302.40
|
8.50
|
275.2
|
G11
|
K.81113
|
44.81
|
378.10
|
11.29
|
37.6
|
Table 8. Sugar yield, cultivar superiority index and mean rankings of the15 selected genotypes
|
|
Code
|
Genotype
|
Cane yield mean (t/acre)
|
Cultivar Superiority index
|
Mean ranks
|
Static stability
|
G7
|
G.2016-129
|
6.85
|
0.66
|
4.71
|
0.46
|
G15
|
G.T.54-9
|
6.75
|
0.87
|
6.86
|
2.03
|
G2
|
G.2016-168
|
6.71
|
1.17
|
5.43
|
1.30
|
G13
|
G.2005-47
|
6.60
|
1.20
|
5.29
|
0.33
|
G1
|
F-150
|
6.54
|
1.59
|
6.86
|
1.25
|
G9
|
G.2016-95
|
6.04
|
1.87
|
9.29
|
1.37
|
G8
|
G.2016-128
|
5.92
|
2.14
|
9.71
|
0.62
|
G6
|
G.2016-99
|
6.13
|
2.46
|
7.79
|
1.04
|
G12
|
G.99-80
|
6.02
|
2.71
|
8.43
|
3.66
|
G3
|
G.2016-158
|
6.15
|
2.88
|
7.57
|
1.73
|
G14
|
G.2000-5
|
5.86
|
3.26
|
8.50
|
1.47
|
G10
|
G.2009-11
|
5.63
|
3.40
|
9.57
|
0.68
|
G11
|
K.81113
|
5.25
|
4.35
|
10.57
|
0.89
|
G4
|
G.2016-74
|
5.63
|
4.53
|
8.71
|
2.43
|
G5
|
G.2016-62
|
5.18
|
4.92
|
10.71
|
1.70
|
GGE biplot: genotypic discriminating ability and representativeness of the studied environments
The GGE -biplot method showed that the PC1 and PC2 could explain 65.98% and 64.11% of total GEI variation for cane and sugar yields, respectively (Figs. 3, 4). Stable varieties and environments with small IPCA-1 and IPCA-2 scores are close the origin of the GGE biplot graph (22). Which-won-where GGE-biplot charts are separated by an equality line into sectors in which dissimilar mega environments can be noticed (22, 23). In this experiment, the equality line divided the studied environments into six mega- environments for cane yield and four mega- environments for sugar yields (Figs. 2, 3, 4). For cane yields, the first mega environment consisted of E1 and E4 (Fig. 3), while the first mega environment for sugar yields included E1, E2 and E5 (Fig. 4). Fig. 3 and 4 help visualize the distance between each environment and the perfect environment, ‘‘model studied environment’’, which is at the middle of the concentric circles. Therefore, E1 and E4 for cane yield and E1, E2 and E5 for sugar yield, respectively were the greatest representative environment and had the maximum ability for discriminating varieties with respect to cane and sugar yields.
The vertex clone connected by the polygon in Fig. 5 were G14 and G7 for cane yield (Fig 5a). Additionally, G7 (G2016-129) was the vertex clone for sugar yield (Fig. 5b) . The vertex clones were those extreme from the origin of the GGE biplot, signifying that these were either the best performers in terms of sugar yield in all or some of the environments based on their direction from origin (24).