EXAMPLE SAS PROGRAM #3 FOR ESTIMATING
HERITABILITY AND ITS STANDARD ERROR
Example SAS codes correspond to J.B. Holland, W.E. Nyquist, and C.T. Cervantes-Martinez,
"Estimating and Interpreting Heritability in Plant Breeding: An Update,"
submitted to Plant Breeding Reviews. Manuscript available on request:
Heritability based on regression of F2:3 progeny means on individual F2
parents and based on variance among F2:3 families evaluated in an unbalanced,
Data are taken from Holland et al. (1998)
Theor. Appl. Genet. 96:232-241.
Briefly: southern rust scores were made on 140 individual F2 (S0) plants
in Florida, 1991. Plants were also self-pollinated.
Self-pollinated progeny of each individual F2 (F2:3 or S0:1 families) were
grown in replicated trials in North Carolina, 1991. Scores were made on
the basis of mean progeny response to southern rust disease.
Selected F2:3 families were also grown in replicated trials in North Carolina,
Holland et al. (1998) estimated heritability on the basis of (1) offspring-parent
regression using 1991 NC means on 1991 FL scores, (2) a second estimate
based on variance components estimated from replicated evaluation of F2:3
families in 1991 NC, and (3) an estimate of "repeatability" on the basis
of variance among selected (not random!) F2:3 families in 1991 and 1994
SAS code is given below to improve the efficiency of heritability estimation.
First, offspring-parent regression is augmented by inclusion of information
from NC 1994 environment on offspring. Second, heritability estimate
based on F2:3 families is augmented by inclusion of NC 1994 data. This
eliminates the need for the estimate of "repeatability" from selected F2:3
lines, and also eliminates bias due to GE interaction variance that was
present in the original estimate of heritability on the basis of F2:3 family
data from a single environment (1991 NC).
To perform the analysis you need to download the following two files:
Original data on a single plant basis for F2s or on a plot basis for F2:3
families is available in an Excel spreadsheet
. To use the SAS code given, this spreadsheet must be open when running
the SAS program!
for conducting heritability estimation analyses.
You can compare your results to mine, found in the
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