than on their
own roots as seedlings.

DR. CRANE: How old are your oldest grafts?

MR. OAKES: Put on in 1938?

DR. CRANE: That's 15 years.

MR. STOKE: I have them at least 20 years.

MR. BECKER: Mine are twenty.

DR. MACDANIEL: Mr. Moderator, I have in my brief case a translation of
the French book on walnut culture, and there is a section on root
stocks. This was a publication issued about 1941, and according to that
book, _Juglans Nigra_ is the best stock they have for general use in
France. They have reported no difficulty on this. A second one they were
trying of the American walnuts, with some promise, was _Juglans major_,
the Arizona black walnut.

DR. CRANE: The reason why I asked, as I reported in previous
meetings--they are having very serious difficulty in Oregon and in parts
of Washington with graft union trouble which is known as "black line."
All or practically all of the walnuts in both Oregon and California and
also what few are grown in Washington have been propagated on the
Northern California black walnut, _Juglans Hindsii_. No graft union
trouble evidence shows up before the tree has been grafted about 8
years, and then such cases are very rare. But after the trees or the
grafts attain an age of 15 years or more, graft union failures are
numerous. For three years now we have been making surveys in the State
of Oregon, and we have surveyed tree by tree, year after year, the same
orchards, the same trees, and our observations now go into the
thousands, and we find that this black line is a terrifically serious
thing. In some orchards 22 per cent of the trees will develop black line
in one year's time. So, you see, at that rate it would only take you
five or six years with a good bearing orchard until you wouldn't have
any.

DR. MACDANIEL: Is that always with the Franquettes?

DR. CRANE: That is not only true with Franquettes but also with other
varieties in California, even in Contra Costa County.

MR. STOKE: Where those trees are so grafted, does it tend to overgrow,
or just the opposite?

DR. CRANE: No, it appears much like our _Crenata-mollissima_ chestnut
graft union failure.

MR. STOKE: Is there a tendency for the top to be more vigorous, to have
more growth, or vice versa or is growth uniform?

DR. CRANE: It may be uniform. Depends somewhat on the varieties and the
seedlings. There may be some overgrowth or some outgrowth, but there is
only one test for it, and that is at the gr