I have got the negative heritability (-3%) for Harvest Index in pooled analysis for RILs. But interestingly the heritability for harvest index was high in individual year (75% and 91%). My design was alpha lattice and 300 RILs were evaluated in two stress seasons for heat tolerance in Chickpea. Analysis was done in SAS proc Mixed model.
Could you please tell me why I got these results and if it is okay then how to interpret the results?
Dear it might be due to computational error while performing the analysis. because negativeheritability is never possible. try again to make pool analysis.
Mr kalim is totally right, this problem happens when the error souse is not correctly defined for software. check out your model and try again because negative heritablity is meaningless.
Dear Visalli Sharma!
Negative genetic variances are not uncommon in crop trials. Hence they should be dealt with as such. Negative heritabilities should not be interpreted as such. May be in coming trials it may get some shape. However, it must be reported, so that if there's a plausible explanation for it in the future.
Hope it helps.
Hi...Well in my standpoint I think you could look for some outliers in your data...
1) So do you have outliers in your data?
2) Can you paste the code you are using here?
3)What's the formula you're using to calculate heritability?
Thanks...If you perform the 3 actions above we can discuss...
:D
Dr. Silva,
1. I don't have outliers in my data.
2. Sorry,I don't have codes as I got it done by someone.
3. The formula of heritability, that I used is
H2=Vg/(Vg+Vg*e/e+Ve/e*r)
Vg=Genotypic variance
e= Environvent
r= replication
And sorry for the delayed response.
Many Thanks
Pronob
I think you should use a different method to estimate your variances components, just in case.
Dear Paul, I recommend you to read a very good paper on negative heritability. Despite all the resistance of the scientific community to admit it, I strongly agree with those who think that negative heritability may occur in situations were individuals grouped under similar criteria like genotype are likely to have more divergent traits. Here is the reference:
On Negative Heritability and Negative Estimates of Heritability
David Steinsaltz, Andy Dahl, Kenneth W. Wachter
Genetics June 2020 215: 343-357; https://doi.org/10.1534/genetics.120.303161
Thanks
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