Mean variance of a difference of two genotypic BLUPs

[mbakare]

In a field trial established as RCBD, rep is a block effect and gen is a random effect of genotype. The genotypic blups of each genetic line is derived as

proc mixed data= sampledat method=reml;

class rep gen

model  yield = rep;

random gen/solution

run;

quit;

The random statement return the genotypic value of each gen.How do I obtain the mean variance of a diiference of two genotypic blups?

Thanks

[jiltao]

You can use an ESTIMATE statement in PROC MIXED to compare two genotypes:

estimate 'gen1-gen2' | gen 1 -1;

The predicted difference and the standard error will be produced.