Subscribe Now Subscribe Today
Research Article
 

Generation Mean Analysis for Yield, its Components and Quality Characteristics in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)



R.A. EL-Refaey and U.A. Abd El-Razek
 
Facebook Twitter Digg Reddit Linkedin StumbleUpon E-mail
ABSTRACT

The objective of the present investigation was to estimate genetic variance components and type of gene action controlling yield, its components and quality characteristics of some cotton crosses, by means of the six populations (P1, P2, F1, F2, BC1 and BC2) of the four cotton crosses. Results revealed that the estimated mean effects (m) were highly significant for all traits in all crosses, indicated that these traits were quantitatively inherited. Additive and dominant gene effects were highly significant for No. of bolls/plant, boll weight in the fourth cross, 2.5% span length in the second cross, fiber fineness in the first and fourth crosses, with lager of dominance effects in magnitude than additive ones. Dominance, additivexdominance and dominancexdominance were at least significant for No. of bolls/plant in the first cross, seed and lint cotton yields in the first and second crosses, boll weight in the fourth cross, 2.5% span length and fiber fineness in the first cross and fiber strength in the second cross, indicated that these traits were greatly affected by dominance and their non-allelic interactions. Narrow-sense heritability and genetic advance were low in most cases due to the opposite directions of dominance and dominancexdominance effects resulted in lower overall dominance variance. It could be concluded that heterosis over mid and better parent were highly significant in all crosses for No. of bolls/plant, seed and lint cotton yields/plant with low inbreeding depression.

Services
Related Articles in ASCI
Search in Google Scholar
View Citation
Report Citation

 
  How to cite this article:

R.A. EL-Refaey and U.A. Abd El-Razek, 2013. Generation Mean Analysis for Yield, its Components and Quality Characteristics in Four Crosses of Egyptian Cotton (Gossypium barbadense L.). Asian Journal of Crop Science, 5: 153-166.

DOI: 10.3923/ajcs.2013.153.166

URL: https://scialert.net/abstract/?doi=ajcs.2013.153.166
 
Received: July 19, 2012; Accepted: November 01, 2012; Published: February 02, 2013



INTRODUCTION

Cotton (Gossypium barbadense L.) is one of the most important fiber crops all over the world. In Egypt, its importance is derived from being one of the main sources of foreign currency as well as the principle raw material for the national textile industry and one of the important sources of edible oil (El-Saeidy et al., 2003). The total cultivate began to decline in the last decade, which requires working to increase the production of unit area to compensate the shortfall in the cultivated area. Knowledge of genetic diversity and relationships among breeding materials is essential to the plant breeders for improving the crop (Abd El-Haleem et al., 2010).

Gamble (1962) reported that epistatic gene effects are present in sufficient magnitude in quantitative traits which may alter the breeders account for the breeding method which must be followed. If the additive genetic variance is of major importance, the intra-population selection will be considered as the most effective procedure for gathering the favorable genetic constitutions. If dominance variance especially over-dominant is predominant, then the hybrid program for commercial purpose may be the appropriate choice. Therefore, the estimation of gene action and the inheritance of the traits especially seed yield is an interesting procedure for the breeders in order to formulate the most efficient breeding method to bring about the maximum improvement of the attribute in question. Both additive and non-additive genetic effects control seed cotton yield (Kalsy and Garg, 1988; Tyagi, 1988; Deshpande and Baig, 2003). However, McCarty et al. (2004) reported additivexadditive epistatic effects for the inheritance of seed cotton yield and Basbag et al. (2008) reported heterotic effects in some cotton crosses. Pathak (1975) used six populations (P1, P2, F1, F2, BC1 and BC2) of five upland cotton (Gossypium hirsutum L.) crosses to evaluate genetic effects for fiber traits.

Improvement in textile processing has led to increased emphasis on breeding cotton for improved fiber properties. Fiber fineness determines the texture of cotton fiber. Cotton fiber may be classified as soft and silky or coarse and harsh.

Cotton breeding program based on the genetic information of traits needs to be improved (Rahman and Malik, 2008). Therefore, the present study aimed to obtain useful information about gene action of yield and quality characters as well as the extent of hybrid vigour, heritability and genetic advance in the four cotton crosses.

MATERIALS AND METHODS

The experiments reported herein were carried out during 2007, 2008 and 2009 seasons. The four initial crosses Giza 45xPima S7, Giza 88xPima S7, Giza 90xSuvin and Giza 88xSuvin which designated in the text as first, second, third and fourth cross, respectively. Pedigree, origin and characteristics of the parental varieties are shown in Table 1.

The crosses were developed in 2007 season at the Faculty of Agriculture farm, Tanta University. In 2008 season, F1 plants were selfed and backcrossed to each parent to obtain the F2, BC1 and BC2 for each cross. In parallel, the hybrid seeds were obtained by crossing each two parents of each cross as F1 seeds.

The six populations; P1, P2, F1, F2, BC1 and BC2 of each cross were sown at the experimental farm, Faculty of Agriculture, Tanta University during 2009 season as follows: two ridges for each patent and F1's, seven ridges for BC's and twelve ridges for the F2 plants. Two, seven and twelve ridge plots were used to reduce intergenotypic competition between generations and to sample adequately the genetic variability within generations.

Each ridge of one side comprised of 20 hills spaced at 20 cm apart and 60 cm wide. Hills were thinned later leaving one plant per each hill. All cultural practices were followed for the ordinary cotton fields in the area.

Data were recorded on an individual guarded plant of the six populations for each cross where 20, 20, 25, 200, 120 and 120 plants were chosen from P1, P2, F1, F2, BC1 and BC2 of each cross, respectively, to collect the following traits:

No. of bolls/plant
Boll weight in grams
Seed cotton yield (g)/plant
Lint cotton yield (g)/plant
Lint percentage which calculated as lint cotton yield/seed cotton yieldx100
Seed index
2.5% span length
Fiber fineness
Fiber strength

Table 1: Pedigree, origin and main characteristics of the parental varieties
Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

Statistical and genetic analysis: To determine the presence or absence of non- allelic interactions, scaling test as outlined by Mather (1949) was used. The quantities A, B, C and D and their variances have been calculated to test adequacy of the additive-dominance model in each case. Where:

Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

And

Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

The standard error of A, B, C and D is worked out by taking square root of respectively variances. The t-values are calculated by dividing the effects of A, B, C and D by the respectively standard error. The calculated t-values were compared with tabulated value of t at 5% levels of probability in each test, the degrees of freedom (df) is sum of (df) of various generation involved. The significance of A and B scales indicate the presence of all types of non-allelic gene interactions. The significance of C scale suggests (dd) types of epistasis. The significance of D scale reveals (aa) gene interactions, significance of C and D scale indicates (aa) and (dd) type of gene interactions (Singh and Narayanan, 1993).

Genetic analysis of generation means to give estimates of the types of gene effects were obtained using the relationships given by Gamble (1962).

Jinks and Jones (1958) however, used following formulae to estimate m, a and d components in the absence of non-allelic interactions:

Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

where, Their variances have been computed using following formulae:

Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

And

Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

SE (m) = Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.), SE [ d] = Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.) and SE [h] = Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)
t(m) = m/SE(m), t[d] = d/SE[d] and t[h] = h/SE[h]

Broad+sense heritability (H2) for F2¯ generation was estimated based on the equation:

Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

The genetic variance (Vg) and environmental (Ve) were estimated according to Mansur et al. (1993) as follows:

Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

where, Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.) and Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.) and Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.) are the number of plants of P1, P2 and F1 generations in each cross, respectively.

Narrow-sense heritability (h2) for F2¯ generation was estimated as proposed by Warner (1952).

Where:

Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

The Phenotypic (PCV%) and Genotypic (GCV%) coefficient of variation were estimated as formulae developed by Burton (1952).

The expected genetic advance from selection (Ga) was calculated as the formulae proposed by Johnson et al. (1955), using the selection differential (k) equal 2.06 for 5% selection intensity and heritability in narrow sense.

The predicted genetic advance where the expected genetic gain upon selection was expressed as percentage of F2 mean (Ga%) was calculated following Miller et al. (1958).

The amount of heterosis was expressed as the percentage deviation of F1 mean performance from mid-parent and better parent. Inbreeding depression was calculated as the difference between the F1 and F2 means as a percentage of F1. The "t" test was used to determine the significance of these deviations where the standard error (SE) was calculated as follows:

Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

where, the t is the deviation/SE at the corresponding degrees of freedom.

RESULTS AND DISCUSSION

The data presented in Table 2 revealed the mean performance of the six generations and variance of mean advanced from the four crosses of cotton for the traits in view. These data used to calculate the salling test and six parameters as Gamble procedure. At least one of the scales was significant in the four crosses for all studied traits, except lint percentage in the second and third crosses boll weight in the first and second crosses seed index in the first cross; 2.5% span length, fiber fineness and fiber strength in the third and fourth crosses, where all scales were not significant. However, the significance of any one of the scale reveals the presence of non- allelic interaction as pointed out in Table 3. Hence, for non expected traits additive- dominance model was not sufficient to explain most the genetic variation for the expression of these traits. This show that epistatic effects were contributed to the inheritance of these traits in the crosses pointed out and this might suggest that, the inheritance of these traits is complex and polygenic (Warnock et al., 1998). On the other side, the insignificant of all scales for the excepted traits mentioned, indicating a simple additive-dominance model was adequate for estimating the genetic components of variance of these traits. This indicates that, selection could be practiced effectively in F2 generation for improving theses traits. However, additive gene effects were highly significant in all cases, except lint percentage in the second cross and fiber strength in the fourth cross, indicating that the additive genes were more important than dominant ones in controlling the inheritance of these traits.

The estimated mean effects (m), which reflects the contribution due to over-all mean plus the locus effects and interaction of the fixed loci was found to be highly significant for all studied traits in all crosses, indicted that these traits were quantitatively inherited. From the obtained results (Table 3), it could be detected that, additive [d] and dominant [h] gene effects were highly significant for number of bolls/plant and boll weight in the cross IV, 2.5% span length in the cross II, fiber fineness in the cross I and IV, indicating that both additive and dominance were important for the inheritance of these traits.

It could be observed that dominance effects are several times larger than additive one and this might indicate that dominance gene effects play the major role in controlling the genetic variation of most studied traits. These results are in the same trend with those reported by Abd El-Haleem et al. (2010) and Karademir and Gencer (2010).

Table 2: Analysis of the six generations advanced from four crosses of cotton for yield, its components and some technological characteristics
Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)

Table 3: Estimates of scalling test and type of gene action of four cotton for nine traits
Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)
*,**Significant at 0.05 and 0.01 levels of probability, respectively

However, the three quality characters i.e., 2.5% span length, fiber fineness and fiber strength could be excepted from the latest conclusion, where additive gene effects were highly significant in most crosses and lager in magnitude than dominant ones, which reflect the great importance of additive genes in the inheritance of these traits.

Jagtap (1986) stated that when additive effects are lager than non-additive ones, it is suggested that selection in early segregating generations would be effects, while if the non-additive portion are lager than additive one, the improvement of the characters need intensive selection through later generation. These conclusion are in the same line with those found by Dhillon and Singh (1980), Singh et al. (1983), Lin and Zhao (1988), Mert et al. (2003), Murtaza (2005) and Esmail (2007).

With regard to the negative values observed in most cases either with main effects; [d] and [h] or the non-allelic interactions; [i], [j] and [l], these might indicate that, the alleles responsible for less values traits were over dominant over the alleles controlling high value. However, it could be detected that the effects of additive and dominant genes were in the opposite direction, where its signs were not similar. This was true for all traits in all crosses, except No. of bolls/plant in the first cross, seed cotton yield/plant in the third cross, lint cotton yield/plant in the third and fourth crosses, seed index and 2.5% span length in the fourth cross and fiber strength in the first, second and fourth crosses.

In all crosses for all studied traits, it could be observed that the signs of dominance [h] and dominancexdominance [l] gene effects were opposite, except seed and lint cotton yield in the cross III; 2.5% span length and fiber strength in the cross I, suggesting duplicated type of non-allelic interaction in these traits.

Since none of the sings of [h] were similar to the [i] type of epistasis, it was concluded that no complementary type of interaction was present in the genetic control of the studied traits. However, dominance [h], additivexdominance [j] and dominancexdominance [I] which referred as non-additive genetic variance were at least significant for number of bolls/plant in the cross I, seed and lint cotton yields in the crosses I and II, boll weight in the cross IV, 2.5% span length and fiber fineness in the cross I and fiber strength in the cross II. This would indicate that, these traits were greatly affected by dominance as main effect and their non-allelic interactions as epistatic effects. These results are in good agreement with those reported by Bhardwaj and Kapoor (1998), Esmail et al. (1999), El-Disouqi and Ziena (2001), Abdul-Hafeez et al. (2007), Esmail (2007), El-Beially and Mohamed (2008) and Abd El-Haleem et al. (2010). However, when epistatic effects were significant for a trait, the possibility of obtaining desirable segregates through inter-mating in early segregations by breaking undesirable linkage could be available or it is suggested to adopt recurrent selection for handling the above crosses for rapid improvement. Abo El-Zahab and Amein (2000), Dong et al. (2006), El-Beially and Mohamed (2008) and Hendawy et al. (2009) came to the same conclusion.

Heterosis over mid-parent and better parent, inbreeding depression, heritability in broad and narrow-senses, genetic advance, phenotypic and genotypic coefficient of variations are presented in Table 4. Highly significant heterosis over mid-parent and better parent was observed in all crosses for number of bolls/plant, seed and lint cotton yields/plant with low inbreeding depression.

Table 4: The genotypic and phenotypic analysis of four cotton crosses for nine traits
Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.)
*,**Significant at 0.05 and 0.01 levels of probability, respectively, Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.): Heterosis over mid-parent, Image for - Generation Mean Analysis for Yield, its Components and Quality Characteristics 
  in Four Crosses of Egyptian Cotton (Gossypium barbadense L.): Better parent, P: Potence ratio, ID: Inbreeding depression, H2: Heritability in broad, h2: Narrow-senses, PCV: Phenotypic coefficient of variance, GCV: Genotypic coefficient of variance

Over-dominance (p<+1) is not only the case of heterotic effects but also the non-allelic interactions might be mainly caused this heterosis for these traits. Significant heterotic effects relative mid-parent and better parent were detected in all crosses for lint percentage, boll weight and seed index, except the cross II for boll weight, where the two values were not significant, the cross I for lint percentage and cross VI for seed index, where the values over better parent were positive but insignificant. However, the heterotic effects in most cases pointed out were attributed to over dominance, where potency ratio exceeded the unity (p<+1). The low values of inbreeding depressions reflects the low reduction in the mean of F2¯ generation due to the direct effect of homozygosity, this low reduction might be attributed to the low sensitivity of the present materials to the inbreeding processes. Abdalla (2007) reported that cotton has a relatively low inbreeding depression.

Narrow-sense heritability estimates were-generally-lower than the corresponding broad sense heritabilities, indicating the presence of non-additive gene action. The low h2 estimates which ranged from 1.16-36.86%, suggested that the inheritance is complex. From six generations of four crosses, environmental, additive and dominance variances were estimated to calculate heritability and genetic advance. In most cases, narrow-sense heritability and genetic advance were very low due to the opposite direction of additive and dominance variances. Moreover, the opposite directions of dominance and dominancexdominance effects results in lower overall dominance variance (Table 3). The genetic gains as a parameter for selection efficiency are related to genetic variability and selection intensity. Low genetic gains which an expected results due to the low values of h2 and genotypic (GCV%) and phenotypic (PCV%) coefficient of variability, indicated that phenotypic effect is mainly controlled by environmental variation. Therefore, for selection of the best genotype, it should concentrate mainly on yield components more than yield itself.

CONCLUSIONS

From this investigation it could be concluded that (1) dominance gene effects play the major role in controlling the genetic variance of yield and most of its components, while additive genes were the predominant for quality characters (2) heterosis over mid and better parent were highly significant in all crosses for No. of bolls/plant, seed and lint cotton yields/plant with low inbreeding depression and (3) narrow-sense heritability and genetic advance were very low due to the opposite direction of additive and dominance variances.

REFERENCES

1:  Abd El-Haleem, S.H.M., E.M.R. Metwali and A.M.M. Al-Felaly, 2010. Genetic analysis of yield and its components of some Egyptian cotton (Gossypium barbadense L.) varieties. World J. Agric. Sci., 6: 615-621.
Direct Link  |  

2:  Abdalla, A.M.A., 2007. Inter and intraspecific cotton cross I-Heterosis performance and generations correlation targeted growth, earliness and yield variables of F1 and F2. Egypt. J. Plant Breed., 11: 793-811.

3:  Abdul-Hafeez, A.G., M.A. El-Hity, H.A. El-Harony and M.A. Abel-Salam, 2007. Estimates of genetic parameters using six populations and biparental crosses in cotton (Gossypium barbadense L.). Egypt. J. Plant Breeding, 11: 669-680.

4:  Abo El-Zahab, A.A. and M.M.M. Amein, 2000. Prospectives for breeding short season cotton. Proceeding of the 9th Conference of Agronomy on Combining Ability for Cotton Yield and its Contributing Variables, September 1-2, 2000, Minufiya University, pp: 305-329

5:  Basbag, S., R. Ekinci and O. Gencer, 2008. Heterotic effects and analyses of correlation relating to some characters on cotton. Ankara Univ. Agric. J. Res., 14: 143-147.
Direct Link  |  

6:  Bhardwaj, R.P. and C.J. Kapoor, 1998. Genetic of yield and its contributing traits in upland cotton (Gossypium hirsutum L.). Proceedings of the World Cotton Research Conference, September 6-12, 1998, Athens, Greece, pp: 214-216

7:  Burton, G.W., 1952. Quantitative inheritance in grasses. Proceedings of the 6th International Grassland Congress, August 17-23, 1952, Pennsylvania State College, USA., pp: 277-283

8:  Deshpande, L.A. and K.S. Baig, 2003. Combining ability analysis for yield, economic and morphological traits in American cotton (Gossypium hirsutum L.). J. Res. Angrau India, 31: 28-34.

9:  Dhillon, S.S. and T.H. Singh, 1980. Genetic control of some quantitative characters in upland cotton (Gossypium hirsutum L.). J. Agric. Sci., 94: 539-543.
CrossRef  |  

10:  Dong, J., F. Wu, Z. Jin and Y. Huang, 2006. Heterosis for yield and some physiological traits in hybrid cotton Cikangza 1. Euphytica, 151: 17-77.
CrossRef  |  Direct Link  |  

11:  El-Saeidy, E., V. Scholz and J. Hahn, 2003. Energetic use of crop residues considering especially cotton stalks. Proceedings of the International Conference on New Methods, Means and Technologies for Application of Agricultural Products, September 18-19, 2003, Raudondvaris, Lithuania, pp: 27-32

12:  El-Beially, I.E. and G.I.A. Mohamed, 2008. Estimates of genetic parameters using six populations in Egyptian cotton (Gossypium barbadense L.). Al-Azher J. Agric. Res., 4: 51-64.

13:  El-Disouqi, A.E. and A.M. Ziena, 2001. Estimates of some genetic parameters and gene action for yield and yield components in cotton. J. Agric, Sci., 126: 3401-3409.

14:  Karademir, E. and O. Gencer, 2010. Combing ability and heterosis for yield and fiber quality properties in cotton (Gossypium hirsutum L.) obtained by half diallel mating design. Not. Bot. Hort. Agrobot. Cluj., 38: 222-227.
Direct Link  |  

15:  Esmail, R.M., 2007. Genetic analysis of yield and its contributing traits in two intra-specific cotton crosses. J. Applied Sci. Res., 3: 2075-2080.

16:  Esmail, R.M., F.A. Hendawy, M.S. Rady and A.M. Hamid, 1999. Genetic studies on yield and yield components in one inter and two intra specific crosses of cotton. Egypt. J. Agron., 21: 37-51.

17:  Gamble, E.E., 1962. Gene effects in corn (Zea mays L.): I. Separation and relative importance of gene effects for yield. Can. J. Plant Sci., 42: 339-348.
CrossRef  |  Direct Link  |  

18:  Hendawy, F.A., H.A. Dawwam, R.M. Esmail and E.H. Mahros, 2009. Triple test cross analysis in some cotton crosses. Proceedings of the 6th International Plant Breeding Conference, August 3-5, 2009, Ismaila, Egypt, pp: 3-5

19:  Jagtap, D.R., 1986. Combining ability in upland cotton. Indian J. Agric. Sci., 56: 833-840.

20:  Jinks, J.L. and R.M. Jones, 1958. Estimation of the components of heterosis. Genetics, 43: 223-234.
Direct Link  |  

21:  Johnson, H.W., H.F. Robinson and R.E. Comstock, 1955. Estimates of genetic and environmental variability in soybeans. Agron. J., 47: 314-318.
CrossRef  |  Direct Link  |  

22:  Kalsy, H.S. and H.R. Garg, 1988. Analysis of generation means for metric traits in upland cotton (Gossypium hirsutum L.). Indian J. Agric. Sci., 58: 397-399.

23:  Lin, Y. and L.Y. Zhao, 1988. Estimation of genetic effects on the main fiber quality characteristics in upland cotton. Acta Genet. Sin., 15: 401-408.

24:  Mansur, L.M., A.L. Carriquiry and A.P. Rao-Arelli, 1993. Generation mean analysis of resistance to race-3 of soybean cyst-nematode. Crop. Sci., 33: 1249-1253.
Direct Link  |  

25:  Mather, S.K., 1949. Biometrical Genetics: The Study of Continuous Variation. Dover Publications, Inc., London

26:  McCarty, Jr. J.C., J.N. Jenkins and J. Wu, 2004. Primitive accession derived germplasm by cultivar crosses as sources for cotton improvement: II. Genetic effects and genotypic values. Crop Sci., 44: 1231-1235.
Direct Link  |  

27:  Mert, M., O. Gencer, Y. Akscan and K. Boyac, 2003. Inheritance of yield and yield components in cotton (Gossypium hirsutum L.). Turk. J. Field Crops, 8: 62-67.

28:  Miller, P.A., J.C. Wiliams, H.F. Robinson and R.E. Comstock, 1958. Estimates of genetic and environmental variance and covariance in upland cotton and their implication in selection. Agron. J., 50: 126-131.

29:  Murtaza, N., 2005. Study of gene effects for boll number, boll weight and seed index in cotton. J. Gent. Eur. Agric., 6: 255-262.
Direct Link  |  

30:  Pathak, R.S., 1975. Gene effects for fiber properties in upland cotton (Gosspium hirsutum L.). Tag Theor. Appl. Genet., 46: 129-133.

31:  Rahman, S.U. and T.A. Malik, 2008. Generation means analysis of fiber traits in cotton. Int. J. Agri. Biol., 10: 209-212.
Direct Link  |  

32:  Singh, P. and S.S. Narayanan, 1993. Biometrical Techniques in Plant Breeding. 1st Edn., Kalyani Publishers, New Delhi, India, Pages: 182

33:  Singh, T.H., M.A. Quader and G.S. Chahal, 1983. Estimation of gene effects for some quantitative characters in upland cotton. Cotton Fibers Trop., 38: 319-322.

34:  Tyagi, A.P., 1988. Genetic architecture of yield and its components in upland cotton (Gossypium hirsutum L.). Indian J. Agric. Res., 22: 75-80.

35:  Warner, J.N., 1952. A method for estimating heritability. Agron. J., 44: 427-430.
CrossRef  |  

36:  Warnock, D.F., D.W. Davis and G.R. Gengera, 1998. Inheritance of ear resistance to European corn borer in apache sweet corn. Crop Sci., 38: 1451-1457.

©  2021 Science Alert. All Rights Reserved