Mr. O'Rourke: It may affect the nursery industry. The nurserymen are looking to the Northern Nut Growers Association, Federal bureaus and State experiment stations to guide them in the propagation of desirable trees. We know now that the Chinese chestnut is becoming quite prominent, is becoming quite popular in many sections of the country, and many nurserymen are now getting requests to supply the public in their states with Chinese chestnuts. They, in turn, would like to know what they should do. If they sell Chinese chestnut trees which have been propagated vegetatively and they only grow five, eight, 10 or 15 years and then die, it's going to come back on the nurserymen. They should like to know whether they should do that or whether they should rely upon seedlings which they can develop into pure lines as best they may.
Now, that really is a serious question. I am wondering from what Mr. Hardy has told us today if it may not be an understock problem, and if it is an understock problem—if there are certain strains of understock which are compatible with certain scions, possibly we should ask for some investigations, some more research to be done in this direction.
Then possibly, on the other hand, we should also ask that certain investigations be carried out so that we will have some idea of the inheritable characters that may be "fixed" through seed selection. I really think that this seed selection should be very seriously considered, and that nurserymen in particular and the public in general would benefit greatly by such consideration.
Mr. Hardy: Mr. Chase, may I make this suggestion: I think it is something that a number of individuals could try, perhaps they should be backed up by agricultural institutions, either Federal or State. We are all interested and concerned with stocks, and I think a large part of our trouble with grafting chestnuts is a stock-scion relationship.
We have some top-worked trees 13 years old that are just as healthy, just as normal as they can be. We have some top-worked trees of various ages below that. The graft-union is good; they are just as healthy and continue to be as productive and vigorous as the parent tree. Where there is incompatibility we run into difficulties very shortly. To a large extent I think we are involved with two problems in the trouble with incompatibility, or perhaps I should say the dying, of grafted trees. One is a stock-scion relationship, the other a mechanical problem.
I think there are these two types of incompatibilities. Now, as to the mechanical part—that can be improved through developing the art of grafting or budding, whichever works out best. The other will require quite a lot of study, perhaps the development of certain strains of the root stocks for certain scion varieties.
I have made this suggestion to two or three. I have started the work myself by putting out with friends two or three or four trees. After they get up to a size where I can top-work them, I will top-work with two varieties. Perhaps I will put Nanking and Kuling on two trees at one particular place. Two or three miles away I will put Kuling and Meiling on two others. At another place I will put Nanking and Meiling. I will get reciprocal pollination, because the chestnut is necessarily cross-pollinating.[15] I can then plant seedlings from both parents, each pollinated by the other. Then by grafting those varieties onto those seedlings stocks I can find out whether there is any reason to go into the work of developing seed orchards of two varieties whereby Meiling pollinated by Kuling may produce the best, most vigorous, most uniform seedlings on which Kuling can be propagated. And by propagating Kuling on such seedlings—the seedlings of such inheritance—we may get 100 per cent of good grafts.
The industry needs a lot of help, and I think it is a matter of time until those things are worked out, but it is going to take time and money and plenty of good effort to work out that problem. I think it probably should be worked out.
Mr. Bush: I don't like the word "incompatibility", and I hardly believe in it, and I presume most of you know that. I have Chinese on European stock, and it has been there for 20 years or more, grafted high. I have Chinese on Japanese grafted under the ground. I think a good deal of our damage is done from wind, from cold, and from sun on the graft just above the ground. I suspect that grafting at that point is what is the matter with many trees in the TVA plantings and others that had low survival. Of late years when I did the grafting (in the last five or six years) I cut the stock underneath the ground and stuck the graft under the ground and seemingly I got far better results. Some of those graft failures showed up. I laid that largely to mechanical damage, and again with the Japanese, particularly, I laid it on the time when the sap comes up. Call it what you will, but the timing of the growth of the two trees is different and we had trouble there. I have grafted some very widely different kinds of chestnuts on the tops of other chestnuts, and am getting them to grow. When we see the break start, we take a twig from below and break and put it above, cut through the cambium and nail it on and they will heal over and the defect disappears. So, again, it seems to be mechanical.
Mr. McDaniel: I believe from observations on a number of trees, particularly Dr. Richards' in West Tennessee, that a large part of our so-called incompatibility in this State is due to winter injury to the stock. So what Dr. Richards meant, evidently, was that he was rather successful in getting a "take" from last summer's propagation but the stock then failed below the union this spring. I saw his trees, and they had the typical discoloration of bark and the dying of various bark areas—these girdling the whole tree in a number of instances. [See Richards' paper in this report.] I would agree in general with what Mr. Bush has just said, but there are certain other instances in which we think the only word for what we see is "incompatibility."