Genetic variability, character association and path analysis in sugarcane genotypes

Figures & data

Table 1. Variability, broad sense heritability and genetic advance estimates for 16 phenotypic traits of 196 genotypes of sugarcane obtained from 14 countries.

Traits	Range	Range unit	Mean ± SE	σ^2e	σ^2g	σ^2p	ECV	GCV	PCV	H^2	GA	GAM
SPN45	1,839–24,368	22,529	10,071 ± 1.66	25.86	25.35	51.21	23.34	23.11	32.85	0.50	7.30	33.50
TL3MAP	8,966–55,172	46,206	29,671 ± 3.21	96.72	353.62	450.34	15.22	29.11	32.85	0.79	34.33	53.14
TL4MAP	5,977–46,897	40,920	24,544 ± 4.42	183.77	235.93	419.71	25.35	28.72	38.31	0.56	23.72	44.36
TL5MAP	9,223–60,230	51007	31,114 ± 5.38	277.59	244.08	521.67	24.60	23.07	33.73	0.47	22.01	32.51
NMS	9,655–50,345	40,690	27,758 ± 4.76	213.24	136.13	349.37	24.15	19.30	30.91	0.39	15.00	24.81
SL (m)	0.75–2.25	1.50	1.55 ± 0.19	0.07	0.04	0.10	16.91	12.27	20.89	0.35	0.23	14.85
NI	11.0–33.4	22.40	20.78 ± 3.15	19.85	8.84	28.69	21.44	14.31	25.78	0.31	3.40	16.36
IL (cm)	0.046–0.136	0.0897	0.08 ± 0.01	0.00	0.00	0.00	18.70	12.92	22.38	0.33	0.01	15.37
SD (cm)	2.027–3.485	1.458	2.58 ± 0.16	0.05	0.06	0.11	8.65	9.33	12.72	0.54	0.36	14.09
SCW (kg)	0.398–1.60	1.202	0.86 ± 0.16	0.05	0.02	0.07	26.96	16.45	31.58	0.27	0.15	17.65
CY (t ha^−1)	20.97–135.31	114.34	70.56 ± 13.42	360.10	275.47	635.58	26.89	23.52	35.73	0.43	22.51	31.90
Brix (%)	16.37–23.5	7.13	20.04 ± 0.96	1.84	1.13	2.97	6.77	5.30	8.60	0.38	1.35	6.73
Pol (%)	11.63–20.87	9.24	17.19 ± 1.02	2.09	1.75	3.84	8.41	7.69	11.39	0.46	1.84	10.69
Purity (%)	68.82–94.58	25.76	85.73 ± 2.50	12.46	8.48	20.94	4.12	3.40	5.34	0.41	3.82	4.46
RS (%)	6.25–14.47	8.22	11.41±0.90	1.63	1.34	2.97	11.18	10.15	15.10	0.45	1.60	14.06
SY (t ha^−1)	1.829–20.422	18.59	8.12±1.58	5.01	5.88	10.90	27.59	29.88	40.67	0.54	3.67	45.22

Notes: σ2g: genotypic variance; σ²e: environmental variance; σ2p: phenotypic variance; ECV (%): environmental coefficient of variance; GCV (%): genotypic coefficient of variance; PCV (%): phenotypic coefficient of variance; H² (%): broad sense heritability, GA: genetic advance, GAM (%): genetic advance as percentage of the mean. SPN45: the number of sprouted buds per plot 45 days after planting; TL3MAP, TL4MAP and TL5MAP: number of tillers per plot three, four and five months after planting, respectively; NMS: the number of millable stalks per plot; SL: stalk length in meters; NI: number of internodes per stalk in centimetres; IL: internodal length in centimetres; SD: stalk diameter in centimetres; SCW: single cane weight in kilograms; CY: cane yield in tons per hectare; RS: recoverable sucrose percent; and SY: sugar yield in tons per hectare.

Table 2. Genotypic correlation coefficients between eleven-agromorphological and five biochemical traits of 196 sugarcane genotypes gathered from 14 different countries.

Traits	SPN45	TL3MAP	TL4MAP	TL5MAP	MSN	NI	SL (m)	IL (cm)	SD (cm)	SCW (kg)	CY (t ha^−1)	Brix (%)	Pol (%)	Purity (%)	RS (%)	SY (tha^−1)
SPN45		0.45**	0.43**	0.41**	0.23**	−0.06^NS	−0.24**	−0.13^NS	−0.04^NS	−0.11^NS	0.05^NS	−0.06^NS	−0.05^NS	−0.01^NS	−0.04^NS	0.03^NS
TL3MAP			0.82**	0.84**	0.51**	0.25**	0.25**	−0.07^NS	−0.14*	0.14^NS	0.52**	0.08^NS	0.07^NS	0.07^NS	0.07^NS	0.46**
TL4MAP				0.90**	0.54**	0.27**	0.21**	−0.09^NS	−0.2**	−0.03^NS	0.52**	0.04^NS	0.07^NS	0.09^NS	0.07^NS	0.46**
TL5MAP					0.86**	0.07^NS	0.18*	0.05^NS	−0.52**	−0.28**	0.58**	−0.03^NS	−0.03^NS	−0.04^NS	−0.04^NS	0.46**
MSN						−0.09^NS	−0.02^NS	0.05^NS	−0.80**	−0.7 **	0.59**	−0.09^NS	−0.06^NS	−0.003^NS	−0.05^NS	0.49**
NI							0.38**	−0.63**	−0.15*	0.12^NS	0.26**	0.03^NS	0.16*	0.37**	0.23**	0.26**
SL (m)								0.47**	−0.15*	0.42**	0.68**	0.10^NS	0.09^NS	0.03^NS	0.09^NS	0.55**
IL (cm)									0.04^NS	0.22**	0.28**	0.05^NS	−0.07^NS	−0.30**	−0.13^NS	0.19**
SD (cm)										0.79**	0.07^NS	0.14^NS	0.09^NS	0.026^NS	0.08^NS	0.41**
SCW (kg)											0.70**	0.34**	0.29**	0.13^NS	0.27**	0.67**
CY(t ha^−1)												0.22**	0.23 **	0.178*	0.23**	0.98**
Brix (%)													0.97 **	0.65**	0.93**	0.57**
Pol (%)														0.85**	0.99**	0.61**
Purity (%)															0.93**	0.49**
RS (%)																0.61**
SY (tha^−1)

Note: SPN45: sprouted bud numbers per hectare at 45 days after planting; TL3MAP, TL4MAP and TL5MAP: tiller numbers per hectare at three, four and five months after planting, respectively; NMS: millable stalk numbers per hectare; SL: mean length of stalk in meters; NI: internodal numbers per stalk; IL: length of internodes in centimetres; SD: stalk girth or diameter in centimetres; SCW: single stalk or cane weight in kilograms; CY: cane yield in tons per hectare; RS: recoverable sucrose percent; and SY: sugar yield in tons per hectare. Alpha = 5%. ‘**’ = p < 0.001; ‘*’ = p <0.01 and ‘ns’= p > 0.05.

Table 3. Genotypic path coefficients between sugar yield and ten-agromorphological and two biochemical traits of 196 sugarcane genotypes obtained from 14 different countries.

Traits	Indirect effects												Direct effects
	SPN45	TL3MAP	TL4MAP	TL5MAP	MSN	SL (m)	IL (cm)	SD (cm)	SCW (kg)	CY (t ha^−1)	Brix (%)	RS (%)
SPN45		−0.06	−0.07	0.05	0.08	−0.11	0.04	−0.02	0.06	0.04	−0.03	0.00	0.07
TL3MAP	0.03		−0.14	0.11	0.17	0.12	0.02	−0.10	−0.07	0.44	0.04	0.00	−0.14
TL4MAP	0.03	−0.11		0.12	0.17	0.10	0.03	−0.16	0.02	0.42	0.02	0.00	−0.18
TL5MAP	0.03	−0.12	−0.16		0.28	0.08	−0.02	−0.39	0.15	0.47	−0.02	0.00	0.13
MSN	0.02	−0.07	−0.09	0.11		−0.01	−0.01	−0.60	0.37	0.49	−0.05	0.00	0.33
SL (m)	−0.02	−0.04	−0.04	0.02	−0.01		−0.13	−0.12	−0.22	0.57	0.05	0.00	0.47
IL (cm)	−0.01	0.01	0.02	0.01	0.02	0.21		0.03	−0.11	0.24	0.06	0.00	−0.28
SD (cm)	0.00	0.02	0.04	−0.07	−0.26	−0.07	−0.01		−0.41	0.07	0.08	0.00	0.75
SCW (kg)	−0.01	−0.02	0.01	−0.04	−0.23	0.20	−0.06	0.59		0.59	0.18	0.00	−0.52
CY (t ha^−1)	0.00	−0.07	−0.09	0.07	0.19	0.32	−0.08	0.06	−0.37		0.11	0.00	0.83
Brix (%)	0.00	−0.01	−0.01	0.00	−0.03	0.04	−0.03	0.11	−0.18	0.18		−0.01	0.51
RS (%)	0.00	−0.01	−0.01	−0.01	−0.02	0.04	0.03	0.07	−0.14	0.20	0.48		−0.01
Residual: 0.117

Note; number of internodes per stalk, pol percent and purity percent were excluded from path coefficient analysis due to their severe multicollinearity problem.

SPN45: sprouted bud numbers per hectare at 45 days after planting; TL3MAP, TL4MAP and TL5MAP: tiller numbers per hectare at three, four and five months after planting, respectively; NMS: millable stalk numbers per hectare; SL: mean length of stalk in meters; NI: internodal numbers per stalk; IL: length of internodes in centimetres; SD: stalk girth or diameter in centimetres; SCW: single stalk or cane weight in kilograms; CY: cane yield in tons per hectare; RS: recoverable sucrose percent; and SY: sugar yield in tons per hectare.

Data availability statement

Data related to this study can be found from the corresponding author on releasable request.