The analysis of variance (ANOVA) exhibited significant differences and confirm the presence of variations among genotypes for traits namely plant height, number of bolls per plant, number of sympodial branches per plant, boll weight, yield of seed cotton, seed index, fiber length, fiber strength and fiber fineness (Table 1). Actually, these genotypes are significantly different from each other and significant differences allow the breeder to proceed for further analysis useful for selection of suitable candidate parental lines. In later stage this data was used for correlation and heritability analysis.
Table 1
Analysis of variance of various quantitative traits for F1 population and parents in upland cotton
SOV | DF | PH | NB | SB | BW | GOT | SI | SCY | FL | FS | FF |
Rep. | 2 | 2.21ns | 2.88ns | 4.39* | 4.77* | 5.88ns | 0.29ns | 4.63ns | 4.65* | 5.68* | 0.35ns |
Gen. | 24 | 3.92** | 2.17* | 1.93* | 1.86* | 10.70** | 2.15* | 16.21** | 2.13* | 2.48** | 3.37** |
Err. | 48 | - | - | - | - | - | - | - | - | - | - |
** = Highly significant p ≤ 0.01, *= Significant p ≤ 0.05 |
Where, PH (plant height), BP (bolls per plant), SB (number of sympodial branches per plant), BW (boll weight), GOT (ginning out turn), SI (seed index), SCY (seed cotton yield), FL (fiber length), FS (fiber strength) and FF (fiber fineness). |
Correlation Coefficient Analysis
Correlation coefficient analysis measures the relationship between various plant characters. The estimation of genotypic and phenotypic correlations among these traits are helpful for initiating breeding programs. If correlation between two traits is positive and it is significant then improvement in one trait will exert significant impact on other trait. In this way selection for one character will also improve the other associated traits. Plant height had positive and significant linkage with number of bolls/plant, number of sympodial branches per plant, ginning out turn, seed cotton yield, fiber length and fiber fineness (Table 2). It had positive but non-significant association with boll weight. However, plant height had negative and non-significant relationship with fiber strength. Number of bolls per plant had positive and significant association with plant height, number of sympodial branches per plant, boll weight, seed index, seed cotton yield and fiber strength whereas had positive but non-significant relationship with ginning out turn and fiber fineness. It had negative but non-significant correlation with fiber length. Number of sympodial branches per plant had positive and significant relationship with all of traits except seed index and staple length. Boll weight had positive and significant correlation with number of bolls per plant, number of sympodial branches per plant, 100 seed weight, staple length and fiber fineness whereas rest had positive but non-significant association whilst negative and non-significant relationship with ginning out turn. Ginning out turn had positive and significant linkage with plant height, seed cotton yield, number of sympodial branches per plant and fiber length. It had positive but non-significant association with number of bolls per plant. However, ginning out turn had negative and non-significant correlation with boll weight, 100 seed weight and fiber strength and fineness. Seed index had positive and significant linkage with number of bolls per plant, boll weight and fiber length while had positive but non-significant correlation with plant height, number of sympodial branches/plant, yield of seed cotton and fiber fineness. It had negative and non-significant relationship with ginning out turn and fiber strength.
Table 2
Correlation among various traits of Upland cotton grown in filed conditions
Traits | PH | BP | SB | BW | GOT | SI | SCY | FL | FS |
BP | 0.16* | | | | | | | | |
SB | 0.63** | 0.17* | | | | | | | |
BW | 0.05 | 0.21** | 0.07* | | | | | | |
GOT | 0.34** | 0.02 | 0.22* | -0.04 | | | | | |
SI | 0.08 | 0.25* | 0.09 | 0.51** | -0.02 | | | | |
SCY | 0.29** | 0.54** | 0.39** | 0.18 | 0.28** | 0.02 | | | |
FL | 0.20* | -0.04 | 0.06 | 0.20* | 0.19* | 0.17* | 0.03* | | |
FS | -0.16 | 0.19* | 0.27* | 0.12 | -0.06 | -0.05 | 0.33** | -0.02* | |
FF | 0.08* | 0.04 | 0.17* | 0.27* | -0.14 | 0.26 | -0.06 | 0.11* | -0.05 |
Where, PH (plant height), BP (bolls per plant), SB (number of sympodial branches per plant), BW (boll weight), GOT (ginning out turn), SI (seed index), SCY (seed cotton yield), FL (fiber length), FS (fiber strength) and FF (fiber fineness). |
Seed cotton yield had positive and significant association with plant height, number of bolls per plant, number of sympodial branches per plant, ginning out turn, staple length and fiber strength. It had positive but non-significant correlation with boll weight, seed index and fiber fineness whereas had negative and non-significant association with fiber strength. Fiber length had positive and significant linkage with plant height, boll weight, ginning out turn, seed index, fiber fineness and seed cotton yield while had positive but non-significant correlation with number of sympodial branches per plant. Staple length had negative and significant association with fiber strength while had negative and non-significant relationship with number of bolls/plant and fiber fineness. Fiber strength had positive and significant association with number of bolls per plant, number of sympodial branches per plant, and seed cotton yield whereas had positive and non-significant correlation with boll weight. It had negative and significant linkage with fiber length while had negative and non-significant relationship with plant height, ginning out turn and seed index. Fiber fineness had positive and significant correlation with plant height, number of sympodial branches per plant, boll weight, and staple length whereas had positive and non-significant association with number of bolls per plant and seed index. It had negative and non-significant linkage with ginning out turn, yield of seed cotton and fiber strength.
Estimates Of Heritability
Heritability (B.S) were ranged from medium to high for various yield and fiber related traits (Table 3). Among these traits plant height, number of bolls per plant, GOT, seed index, seed cotton yield, fiber length, strength and fineness showed high heritability estimates i.e. 74.48, 53.87, 90.65, 53.42, 54.56, 52.95, 59.66 and 70.42 respectively. While the traits sympodial branches per plant and boll weight exhibited medium estimates of heritability i.e. 48.06 and 46.66. The process of selection could be useful for characters with high heritability values.
Table 3
Range of heritability of various traits of cotton grown in field conditions
Traits | Heritability (%) | Status |
Plant height | 74.48 | High |
Sympodial branches/plant | 48.06 | Medium |
Number of bolls/plant | 53.87 | High |
Boll weight | 46.66 | Medium |
Ginning out turn | 90.65 | High |
Seed index | 53.42 | High |
Seed cotton yield | 54.56 | High |
Fiber length | 52.95 | High |
Fiber strength | 59.66 | High |
Fiber fineness | 70.42 | High |
High > 0.5, Medium 0.2–0.5, Low < 0.2 |
Mean Comparison For Certain Traits
Among parents the mean values for the character plant height, the genotype A555 had lowest mean value 99.93 cm, while CIM-632 exposed maximum mean value 124.73 cm (Fig. 1-A). Whereas, hybrid IUB-222 × NIAB-414 exhibited minimum mean value 88.07 cm, whereas NIAB-414 × CIM-632 showed highest mean value 127.2 cm. Mean data number of bolls per plant showed that genotypes VH-367 exposed minimum number of bolls per plant with lowest mean value 16.26 whereas IUB-222 showed maximum value 32.13 followed by CIM-632, NIAB-414 and A555 having mean values i.e. 26.53, 23.26, 23.13 correspondingly (Fig. 1-B). Crosses, VH-367 × CIM-632 indicated highest mean value 32.93 which is greater than NIAB-414 × IUB222, NIAB-414 × CIM-632 and A555 × IUB-222, having mean values i.e. 32.53, 31, 30.4 and 28.2 respectively. Number of sympodial branches per plant, VH-367 showed highest mean value 23.13 which is greater than A555, NIAB-414 and IUB-222 having mean values i.e. 22.66, 20.93 and 20.86 respectively (Fig. 1-C). Among the hybrids, A555 × IUB-222 had minimum mean value 18.86 for this trait, whereas VH-367 × NIAB-414 indicated maximum number of sympodial branches 25.73. Genotype, CIM-632 had minimum mean value for boll weight 1.83 g whereas VH-367 exposed maximum mean value 2.46 g (Fig. 1-D). Hybrids, IUB-222 × VH-367 revealed lowest mean value but VH-367 × NIAB-414 showed maximum boll weight. NIAB-414 had minimum mean value for ginning out turn 38.03% while IUB-222 had maximum ginning out turn 42.32% (Fig. 1-E). NIAB × IUB-222 showed minimum mean value 35.46% whilst hybrid VH-367 × CIM-632 revealed maximum ginning out turn 46.33% followed by CIM-632 × VH-367, CIM-632 × A555 and A555 × NIAB-414 with estimates of i.e. 45.62, 44.33 and 43.22%.
Furthermore, NIAB-414 and A555 exhibited the minimum and maximum mean estimates 5.07 and 5.64 g respectively for 100 seed weight (Fig. 1-F). Hybrid CIM-632 × VH-367 had minimum seed index 4.62 g whereas CIM-632 × A555 exhibited maximum mean value 5.70 g. While studying the seed cotton yield it was observed that among parents, the genotype IUB-222 had maximum mean value 74.81 g (Fig. 1-G). Crosses of IUB-222 × A555 had minimum seed cotton yield 42.39 g but the hybrid VH-367 × CIM-632 revealed highest mean value 80.17 g as compare to A555 × IUB-222 and NIAB-414 × IUB-222 with mean values i.e. 73.95 and 72.84. CIM-632 indicated lowest mean value 24.71 mm for fiber length, while NIAB-414 had maximum fiber length 26.86 mm (Fig. 1-H). Among the hybrids, A555 × VH-376 had minimum fiber length 24.29 mm, while highest mean value 28.33 mm was shown by CIM-632 × NIAB-414. In case of fiber strength, parent IUB-222 showed minimum mean value 25.42 g/tex whereas VH-367 indicated maximum mean value 29.83 g/tex followed by A555, NIAB-414 and CIM-632 having mean values i.e. 26.35 g/tex, 26.28 g/tex and 25.47 g/tex respectively (Fig. 1-I). Furthermore, CIM-632 × IUB-222 had minimum fiber strength 23.29 g/tex, while VH-367 × NIAB-414 revealed highest value 27.96 g/tex. IUB-222 had lowest mean value 3.31 µg/inch for fiber fineness, while NIAB-414 had highest mean value 5.06 µg/inch (Fig. 1-J). While among the hybrids IUB-222 × NIAB-414 exposed minimum mean value 3.23 µg/inch, but NIAB-414 × IUB-222 had highest mean value 5.44 µg/inch followed by IUB-222 × A555, NIAB-414 × A555 and CIM-632 × IUB-222 with estimates of 5.40, 5.23 and 5.14.