Article

Heritability and Genetic Advance as Selection Indicators for Improvement in Cotton ( Gossypium hirsutum L.)

Journal of Biological Sciences 01/2006; DOI: 10.3923/jbs.2006.96.99
Source: DOAJ

ABSTRACT The investigation pertaining to heritability and genetic advance in cotton genotypes for some quantitative and qualitative traits were undertaken. The results indicated highly significant differences among the parents and F1 crosses for all the traits. Plant height and seed cotton yield per plant displayed moderate to higher estimates of heritability and genetic advance which is indicative of additive with partial dominance type of gene action suggesting the feasibility of selection in the early generation, while bolls per plant, boll weight and staple length exhibited moderate to high heritability and low genetic advance which indicated over dominance type of gene action thereby revealing that selection might be useful if delayed. The traits monopodia and sympodia per plant gave low to moderate heritability and low genetic advance but the trait micronaire value manifested high heritability coupled with low genetic advance.

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    • "However, low genetic gain obtained for boll weight and lint percentage, suggesting selection practice is limited scope for improvement of these traits Table (7). Ahmed et al. (2006) and Esmail (2007) found similar results. On the contrary, for traits with low heritability, the genetic gain will increase if they are selected on a family basis Moreno-Gonzalez and Cubero (1993). "
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    ABSTRACT: Two marker systems, 19 RAPD and 8 agronomic traits were used to estimate the genetic diversity in Egyptian cotton. RAPD primers produced a total of 101 amplicons, which generated 86.25% polymorphism. Number of amplification products ranged from 2 to 7 where percent genetic similarity for the studied primers ranged from 72.2% to 89.9% with an average 81.4%. PIC values of the RAPD markers ranged from 0.855 (UBC 20) to 0.909 (UBC 54) with an average of 0.896 per marker. Highly significant differences were obtained between genotypes for all traits except boll weight, lint percentage and fiber strength. PCV were higher than its corresponding GCV for number of open bolls per plant, boll weight, seed cotton and lint yields per plant. However, no great difference between PCV and GCV for the three fiber characters. Broadsense heritability estimates were ranged from 17.18% to 90.97% for boll weight and fibre strength, respectively. High genetic advance under selection was noted for lint cotton yield per plant, seed cotton yield per plant, number of open bolls per plant, fiber strength, fiber length and micronair value. However, low genetic gain obtained for boll weight and lint percentage. Number of bolls per plant showed high positive phenotypic correlation coefficients with both seed cotton and lint yields per plant. This study of the genetic diversity of Egyptian cotton varieties with RAPD markers and agronomic traits support the need to introduce new alleles into the gene pool of the Egyptian cotton breeding program.
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    • "The potence ratio was greater than unity exhibiting over-dominance for leaf area and petiole length but for seed cotton yield it was 0.75, which suggested partial dominance. The narrow sense heritability (h 2 NS ) estimates for leaf area (0.82), petiole length (0.62) and seed cotton yield (0.71) suggested the possibility of improving these traits through conventional breeding (Saranga et al., 1992; Ahmed et al, 2006). Nature of associations between leaf area and petiole length (r = 0.99 "
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    ABSTRACT: The leaf area, petiole length and seed cotton yield were measured in six generations of a cross between cotton (Gossypium hirsutum L.) varieties (namely, NuCOTN-35B & NIAB-111) to study the genetic mechanisms controlling these characters, and to examine the relationship among them during 2002-2004. Five parameter models, m, (d), (i), (j), (l) for leaf area, while m, (d), (h), (i), (j) for petiole length and seed cotton yield were found adequate for genetic analysis. Genetic analysis through generation means for leaf area (cm 2 ) indicated that this trait is controlled by the genes acting additively and complicated by (additive × additive) (i), (additive × dominance) (j) and (dominance × dominance) (l) interactions. The genetic analysis of the data for petiole length (cm) and seed cotton yield (g) revealed that both additive and dominance gene effects controlled these two traits. Potence ratio was greater than unity for leaf area and petiole length, showing over-dominance for them. For seed cotton yield, the potence ratio of 0.75 revealed partial dominance. Narrow sense heritability for leaf area (0.80), petiole length (0.62) and seed cotton yield (0.71) was moderate, suggesting the chances for improving these characters through selection from the segregating populations. Strong positive associations among the three traits suggest that indirect selection for these photosynthetic activity-enhancing traits would be helpful in improving seed cotton yield in cotton.
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    • "The regression line did not deviate from unit slope, therefore interactions of genes was not involved. These results confirmed the findings of Babar and Khan (1999), Baloch et al. (2000), Amin and Hussain (2000), Azhar et al. (2004) and Haq and Azhar (2005), while Banumathy and Patil (2000), Khan et al. (2001), Cheatham et al. (2003), Subhan et al. (2003) and Ahmad et al. (2006) reported non-additive type of gene action. From the position of array points on the regression line it is clear that the variety Coker-4601 occupied the nearest position from the point of origin so had maximum dominant genes whereas variety Allepo-41 that occupied the farthest position from point of origin possessed maximum recessive genes (Fig. 2). "
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    ABSTRACT: Five American cotton (Gossypium hirsutum L.) varieties namely Coker-4601, MNH-552, S-14, Stoneville and Allepo-41 were crossed in a complete diallel fashion and evaluated in randomized complete block design. Gene action and combining ability effects were estimated for the fiber quality its fineness, staple length, uniformity ratio and strength. Fiber fineness, staple length and fiber strength were found to be controlled by additive type of gene action with partial dominance while fiber uniformity ratio with over dominance type of gene action. For fiber fineness and staple length genotype Coker-4601 was a good general combiner whereas S-14 and Stoneville were good combiner for fiber uniformity ratio and its strength. The cross combinations, Coker-4601 X Stoneville showed better SCA for staple length and fiber strength while Coker-4601 X Allepo- 41 and Coker-4601 X S-14 showed good SCA for fiber fineness and fiber uniformity ratio.
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