DNA isolation by CTAB with Proteinase-K for plant tissue?

I have found that different techniques work for different plant species
depending on the presence of polysachs, phenols, oils . . . there's a
web site for a journal called Biotechniques that would be a good place
for you to start looking for different protocols.

If CTAB protoco is not giving you good quality DNA, try some of the
protocols from these authors:

Wang et al. 1996. An improved isolation of nuclear DNA from leaves of
wild grapevine dried with silica gel. Plant Mol Biol. Reporter
14:361-373

Tabaeizadeh Z., Agharbaoui Z., Harrak H., and Poysa V., (something about
transgenic tomatoes) 1999 Plant Cell Reports 19:197-202

Bernatzky & Tankley Genetics of Actin related sequences in tomato. 1986
Theor Appl Genet 72:314-321

Prince, J. something about DNA extraction from peppers.

Hope this helps,
Deanne Bell