INFLUENCE OF STOCK ON GRAFT AND VICE VERSA
COL. G. B. BRACKETT, DENMARK.
It is, I think, now generally admitted that the stock or root does exert some influence on the graft, but to what extent is still an unsettled question. There is a relationship existing between the top and root of a tree so intimately connecting the two parts that one cannot be effected without the other.
When we graft a tree or insert a bud in a stock and the union is perfected there is a mutual influence maintained between the two. There are instances where the influence of the stock on the graft may be seen, and then again we see the effect of the graft on the stock. For instance, if one hundred apple seedlings are grafted, fifty of them with Ben Davis scions, and fifty with Wine Sap, what nurseryman is there who has had any experience that cannot distinguish one variety from the other by the roots alone.
Some curious features showing the influence of the scion on the stock is seen in some of the variegated plants where it has been noticed that shoots on the body of the tree below where the buds of variegated leafed plants had been inserted bore the variegated leaves, and there are cases on record where an inserted bud had died and variegated shoots were observed to be growing both above and below where the bud had been inserted.
The Gardeners Chronicle records an instance showing the influence of the stock on the scion. A Muscat Grape was worked on the Black Hamburg in the same house with Muscat on its own roots. Those worked on the Hamburg started their growth five or six days in advance of those on own roots, although they are usually two weeks behind the Hamburg they are worked on, but there was no effect otherwise either in the season or on the fruit. This latter fact is so well established that we do not know of any deviation from this law of nature. A Ben Davis or Roman stem grafted on any kind of an apple stock will invariably produce the same fruit.
It is now generally believed by Vegetable Physiologists that the crude sap ascends from the roots through the sap wood to the upper sides of the leaves where it is elaborated by coming in contact with the air exhaling the superfluous water and oxygen and inhaling carbonic acid. It then passes into the veins on the under sides of the leaves to be conducted into the chlorophyl vessels in the bark where it is digested and assimilated on its way into the cambium where it forms the protoplasm or life principle which circulates to every part of the tree or plant and goes to form wood growth or fruit. Now, if we graft a Tallman Sweet apple scion or any other variety on to a crab stock, the sap passes up through the crab stock, to the top of the tree where it undergoes the changes as indicated above and on its downward flow it contains in its protoplasm the primordial cells that go to form Tallman Sweet apples or wood growth, but as soon as it reaches the crab stock it is changed and forms crab wood or crab apples. Mr. Talbot, of Massachusetts, makes this matter still plainer, he says: I have a natural pear tree which many years ago was grafted with the St. Michael, when the pear cracked so badly I grafted it with the Dunmore. Not satisfied with that fruit I grafted it with the Angou. Thus I had four kinds of pear wood growing one above the other.
The wild stock furnished all the sap that passed up through the four kinds of wood which is elaborated digested and assimilated by the Angou leaves and branches, and forms protoplasm in the cambium of the Angou top. It is certainly Angou-protoplasm, for it forms Angou buds wood and fruit, but this same Angou protoplasm passed down a little lower and forms Dunmore cells, wood and fruit, still lower it forms St. Michael wood fruit, etc., lower still the wild fruit of fifty years ago is formed. Every kind of wood imparts something to every parent cell matured in it, that determines what kind of fruit the tree coming from it shall bear, and every tree coming from such a cell must be true to its kind.
In the case of working the peach on the plum stock the effect is due almost wholly to the adaptability of the root to certain soils. When the soil is heavy the plum will thrive better than the peach, and good results are derived from working the peach on the plum stock, but when the soil is light and sandy the peach will do better on its own roots. In the case of working the pear on the quince we see the influence of the stock on the graft in its dwarfing effect which is due to the want of congeniality, for some varieties of pear do not take kindly to the quince on account of the greater dissimilarity between the stock and graft.
Mr. Budd: On the places of very many of our experienced orchardists of Iowa, Illinois and Wisconsin, I have seen during the past summer more evidence of the benefit of top-working the varieties liable to injury of stems than has come under my observation since 1856. While top-working has been discussed from a theoretical standpoint, and some half doubtful evidence for many years, we can now, I believe, lay it down as an accepted doctrine that top-working varieties as hardy as Willow on stocks not subject to stem injury will add to the longevity and productiveness of our orchard trees. The selection of best stock should now have our special attention. In practice we find some unexpected results. For instance, Mr. Pugsley, of Harrison county, pointed to a row in his orchard where a dozen or more of our common varieties were top-worked on Tetofsky. Naturally we would expect imperfect union of such sorts as Willow, Grimes' Golden, Jonathan, etc., on this stock, and where the union was perfect we would expect the scion to outgrow the stock. But in every case the union seemed perfect and the stock and scion made growth so evenly that the point of union could scarcely be told, except from difference in the color of the bark. Mr. Cotta, to whose letter we have listened, believes Whitney's No. 20 the best available stock. Time alone can determine its real merits for this use. Like the Tetofsky, which it much resembles in tree, it may prove valuable.
Mr. Watrous: A. R. Whitney of Lee county, Illinois, believes the Whitney No. 20 the best available stock for top working. He takes up strong one-year grafts and top-works them in grafting room in winter. A main trouble with this plan is the extra amount of cellar room required, and the extra work in taking up, handling, and resetting. We also must experience a loss in growth, in taking up. The plan of whip grafting on the leader in nursery row would seem to be better and cheaper.
Mr. Fluke: I have top-worked on three year old trees of varieties of undoubted hardiness. I have Stark, top-worked, in perfect condition, while the root-grafted trees are dead. In this case the scions were worked on Virginia Crab.
Mr. Budd: Mr. Fluke does not mean Howes' Virginia Crab? The Virginia Crab has wooly leaves and is a rampant grower.
Mr. Patten: The subject under discussion I regard as specially important at this time. Nature has many secrets which the scientists are slow to discover. One of them is the perfect fruit of our choicest varieties when grown on the most acrid crab stock. Mr. Peffer tells of a Tallman Sweet top on a crab stock which produces tine specimens with unimpaired flavor. In some cases where union of stock and graft is not perfect we may get for a time good crops, but the stock is starved on account of the imperfect union of the cambium layers. This is well illustrated in the specimens of cherry on wild plum stock which Mr. Lathrop has exhibited. I have found by experience that Walbridge fails on the crab, when worked on the limbs, but does well when worked on the stem two feet from the ground. I think the Red Siberian crab a valuable stock for a number of varieties. The Bethlemite apple works fairly well on the wild crab stock, though the wood is so dissimilar that it is quite a thing of wonder. I grafted Willow on large yellow crab five feet from the ground, and it has seemed to unite well.
Mr. Smith: We have a tree of Ben Davis in Dubuqne top-worked on Whitney. The top made fine growth, but the stock soon died from apparent starvation.
Mr. Plumb: I have been watching this top working in Wisconsin for a number of years. Beyond doubt there is a limit, which will be over-reached if the question is not properly talked up and written up. Many varieties with us have died as a peach tree dies, from the top down. In other cases the top seemed nearly perfect and the death of the tree resulted from stem injury. We need reports and experiments. We must not jump at the general conclusion that top-working all varieties will be desirable, or that one stock will prove best for all varieties that it will pay us to top-work.