Understanding DESeq2 design, contrast and results
The simplest manner is to not use a wald test, but rather an LRT with a reduced model lacking the factor of interest:

dds = DESeq(dds, test="LRT" reduced=~geno+geno:Treatment)


The above would give you results for Treatment regardless of level while still accounting for a possible interaction (i.e., a "main effect of treatment, regardless of the type of treatment").

As an aside, this is probably a case where the edgeR-preferred way of creating groups of genotype-treatment combinations and then using a model of ~0+group might make your life a bit easier. You'll get the same results (more or less) regardless, but it'll probably be easier for you to think in those terms rather than remembering that the base level will be treatment HS30 and geno prg1.