I am working on the evaluation of some tomato cultivars. I am wondering if you can give some suggestion on how genotypic and phenotypic correlation coefficient calculation and path coefficient analysis work in statistical program. It would be really nice if you can suggest any statistical program that is convenient for this calculation and analysis .
Dear Chea,
As per my knowledge no software gives better results than indostat. it is better you go with indostat.
To my knowledge IBM SPSS software can do correlation coefficient calculation and path coefficient analysis.
The correlation coefficient, denoted by r tells us how closely data in a scatterplot fall along a straight line. The closer that the absolute value of r is to one, the closer that the data are described by a linear equation. Data with values of r close to zero show little to no straight-line relationship.
Surely if you want more detailed step-by-step guidance for calculating r, you can search the internet!
I hope that reading this will be helpful!
Greetings
You can calculate the phenotypic and genotypic correlations together with path coefficcient analyiss in the following manner.
Analysis of Phenotypic and Genotypic Correlation Coefficients will be estimated using the formula given by Johansen et al. (1955); Miller et al. (1958); Singh and Chavdhury (1985). The coefficient of variation at genotypic level was tested for their significance using the formula proposed by Robertson (1959). The formulas are available with the attached documents.
Path Coefficient Analysis can be used to determine the direct and indirect effects of the independent characters on dependent variable and is estimated by simultaneous equation using the formula as applied by Deway and Lu (1959):
rij = pij +∑rikpkj
Where;
rij=mutual association between the ith independent character and the jth dependent characters as measured by the genotypic correlation coefficient.
Pij= components of direct effects of the ith independent character on the jth independent character as measured by the genotypic path coefficients, and
∑rikpkj= summation of components of indirect effects of a given ith independent characters on given jth dependent via all other k independent characters.
For detail information, please get the attached article. Bye for now
Thanks very much for your constructive suggestions. I would also like to know how these analysis can be done in statistical program instead of manual calculation.
Yes it is possible to analyze statistically using SAS computer Software for the GLM using syntaxes for correlation and path coefficient analysis.
Dear Leangsrun,
I don't know if you want to explore the phenotypic difference of different genotypes; if it is true, I suggest you to use the ANOVA, maybe oneway-ANOVA, because the correlation analysis could assumed that both variables are continuous. Besides, I recommend you to take some time to study the SPSS, it is very suitable for the new learners; you can use the "help" document to understand if your data is suitable for the statistical analysis you chose and the example provided which is very easy to understand.
Best wishes!
Wumei
Dear Leangsrun,
You can use META-R software for genotypic and phenotypic correlation analysis. You will find it from the following link. For path analysis you can use " agricolae" package in R software.
http://data.cimmyt.org/dvn/dv/cimmytswdvn/faces/study/StudyPage.xhtml;jsessionid=74130eba75fd31d67bc462ac8909?globalId=hdl:11529/10201&studyListingIndex=0_74130eba75fd31d67bc462ac8909
Dear Leangrun,
I have developed user-friendly computer program for path coefficient analysis which is free to use. you can contact me on [email protected]
with best wishes,
Chea,
You can use the Hmisc package to compute matrix of correlation coefficients in R
http://www.sthda.com/english/wiki/correlation-matrix-a-quick-start-guide-to-analyze-format-and-visualize-a-correlation-matrix-using-r-software
As I mentioned before, I have gave how to analyze manually. If you are unable to go manually, there are two softwares. These parameters can be analyzed using statistical analysis software including SAS and Genres. Please try to get these programs and try the analysis using appropriate syntax. Good luck.
Faithfully yours,
Dear Chea,
As per my knowledge no software gives better results than indostat. it is better you go with indostat.
If you are looking for traits association of multiple years/environments data then meta R is the best option, but traits with heritability below 0.05 are not considered for analysis. For single-season data SPSS can be used easily. Did you find out the solution for single-season data in R package? If yes please share.
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