Alaska Pioneer Fruit Growers Association

GRAFTING FRUIT TREES SUCCESSFULLY

November 9, 1999

 

—by Lamond Hardy

312 N.E. 80th Ave.

Okeechobee, FL 34974

 

(The following article was found by Bob Boyer. It was used with permission from Countryside and Small Stock Journal, v. 79, no. 2. March/April 1995. The methods that Lamond Hardy describes were developed by him beginning in 1931. Regardless of whether one accepts his explanations, his empirical observations speak for themselves.)

 

Part one: Inducing early bearing

 

This article explains how to induce an early bearing age into fruit trees that will match the precocity of any trees produced by vegetative methods taken from mature (fruiting age) par­ent plants. My experience has shown that seedling fruit trees are usually delayed in flowering or fruiting for many years, while plants produced by grafting, cuttings or air- layers (which shall be referred to as “vegetatively propagated”) may fruit within a year or two. However, vegetatively propagated plants must be taken from mature fruiting parent trees to expect this early fruiting phenomenon. If such plants are taken from a “juvenile” seedling tree that has never flowered or fruited, they typically will not flower or fruit until the parent plant (same clone) comes into maturity.

The validity of this has been demonstrated by reversing the premise. I, and others, have observed that if a scion from a young seedling is grafted onto a mature fruiting tree, that scion will pick up the fruiting factor from the root- stock and become an early bearer.

I concluded that there is a hormone connection, when it can be shown that a chip bud taken from a mature citrus tree and grafted onto any young seedling will contain enough of the “wonder” ingredient to produce the desired early fruiting habit. Without the presence of this adult fruiting hormone, some seedling lychee trees have been known to be delayed into fruiting for 30 or more years.

At this point it would seem obvious that all one needs to do to induce a batch of seedlings into early bearing would be to inject those seedlings with the same hormone that a small chip bud seems to contain. Why is this not done? I made this discovery in 1931!

 

A 1931 discovery

 

In 1931 I chip-budded a row of sweet orange seedlings with scions taken from a mature grapefruit tree. Some of the orange seedlings (containing the grapefruit chip-buds) were allowed to retain their seedling tops. I noted that those sweet orange seedlings flowered and fruited at the same early age as the trees grown from grapefruit chip-buds. This caused me to suspect a hormone linkage. When this hormone is chemically identified, manufactured synthetically and injected into seedlings, it will bring about the same early bearing habit as is characteristic of grafted trees, opening up a vast new research frontier. Some examples could include early bearing of seedling groves, and early bearing for selecting improved varieties for disease resistance and fruit quality.

Since my discovery I have conducted many experiments, all of which indicated the hormone connection to early bearing age. One such test was conducted in Okeechobee, Florida, in 1989 to 1991. This experiment involved 100 Rangpur lime trees which began as seed planted in October, 1989, and were in flower within 14 months. The experiment was conducted as follows:

 

  1. In October, 1989, the Rangpur lime seeds were collected and planted.
  2. In March, 1990, the seedlings were chip-budded in their basal area where the diameter size was best for working (soda straw to pencil size.)
  3. In April, 1990, all grafts were released from their plastic wraps and the root- stock tops were removed and rooted in a mist bed.
  4. In January, 1991, at 14 months of age, all of these Rangpur lime plants derived from rooted tops came into full bloom.
  5. A control group of 50 non-treated Rangpur seedlings of the same age did not flower until they were 1-2 years older than the rooted Rangpur tops.

 

I have conducted many other types of experiments to test for the connection of a hormone-related influence to the early bearing habit of vegetatively propagated plants. One involved hypodermically injecting into young seedling plants a concoction extracted from mature, bearing plants of the same species. This seemed a very logical test in trying to zero in on the concept of a hormone-related cause to early fruiting.

The material collected for these hypodermic injections was prepared by grinding in a blender cambium, leaves, and flowers in distilled water. The resulting liquid was filtered and injected by hypodermic syringe into the cambium and sap wood of the young seedling trees.

Success was phenomenal, and has been achieved when tried on several different species such as annonas, citrus, mangoes and avocados. Cross­testing over species line was only conducted between avocado and redbay, using redbay vaccine injected into the avocado. It worked.

When, and if ever, a sophisticated laboratory should identify the “magic” hormone that causes early fruiting, manufactures it synthetically and makes it economically available to plant breeders, it will open a vast new frontier.

 

Part two: “grafting” and “growth” hormones.

 

There are hormones in the enzymes that are growth regulators. These are scattered around the plant, telling it when to produce a leaf or a flower, or when to shed a leaf. I have discovered many plants that will have growth hormones in that area of the stalk below the canopy that can be turned “off” for growth, and will prune any­thing that happens to be there or anything that you put there. It will prune many of our grafts. So if we can turn off this “pruning hormone” and turn on the “growth hormone” it will improve our grafting.

We do not really need to know what the hormone is—just how it works and how we can control it—just like we don’t know why, when you hatch a rare pheasant or quail in an incubator, it will give you crooked toes and crooked tendons. But when you put them under a pigeon, duck or goose or any other kind of bird, they will hatch with practically a 100 percent take. We know it has nothing to do with difference in body temperature because the temperatures of these birds vary by three or four degrees. In an incubator the temperature varies by just a half degree. Something happens. Anyway, we don’t have to know the reason. We just need to know how to do the manipulation to get the results we want.

We know that in spring, a tree is ready to bud out somewhere, but maybe not where we want to put a graft on. In that area below the canopy, many plants have that “turn-off” hormone and will want to prune themselves in that area. And it is not about to accept our graft and make it grow if that hormone is in full occurrence. We want to change that mode and make it ready to promote growth in that area so when we put a graft there it will take, live and grow. Here’s how to do it.

Girdle the branch just above the desired area or “hat-rack” the branches above that point. Then, approximately two weeks after that, when the plant is starting to throw out new buds in that area, where the growth is “turned on,” you put your graft on, using all the care of selecting and handling the scions properly and keeping them out of the sunlight. Place it on there and you can get 100 percent take.

 

First suspicions

 

I first became suspicious of a “turn-on” hormone and a “turn-off” hormone when I grafted 76 grafts on a cypress tree I wanted to use as a stockpile for a superior variety. It had about 76 side branches about the size of a lead pencil and I wanted to replace all of those branches with a superior variety. So about eight inches out from the trunk I put on 76 grafts of the best-style veneer graft of the best-prepared bud wood I could get. And it was practically 100 percent failure. One graft was partially alive and after many weeks it finally put out a little weak bud.

The turn-off hormone was in full force in that tree. The tree was wanting to prune itself in the area of the grafts. It was anxious to grow out the tips of its branches and on its top. But in the area where I chose to put the buds, the turn-off or “pruning” hormone was in full swing, so I had practically 100 percent failure.

All I needed to have done was one of two things: lop off all those 76 branches about 12 inches out, or girdle them about 12 inches away from the trunk and then wait three or four weeks until I could see little buds start in that area where they had previously failed. I did this, and redid those 76 limbs with 76 buds of the same refrigerated budwood that had failed a month or two earlier, and I got 100 percent take. I have repeated this experiment several times. This is why I had failures on some occasions and complete successes on others.

Now another little story that fits that category of thinking: There was a patch of wild persim­mons near Gainesville. The fruits were about as large around as your thumb or finger. I wanted to graft them with a new variety that someone told me was the greatest thing out. I grafted those persimmons. Some took, and some didn’t.

This was the spring of the year when the tops were flushing. That should have been the proper time. The budwood was kept in sphagnum moss in the refrigerator, and should have been good any time in the next six months. But some of them took and grew okay, and some failed. I replaced the failures, and they failed. I replaced them again and they still failed. I found plants that just didn’t seem to be in the mood to accept a graft! In other words, those particular plants were programmed to prune in that area. Later I found that those plants that failed were all root-connected. They were the same clone and all had the same degree of turn-off hormone.

Well, I had already learned from my cypress tree experiments that there was a way to turn them on. I girdled them all just above where I was to put the new grafts. Some I cut off in that area and some I went a little higher and hat- racked them. After a few weeks, when they //////////////////////////////////////////////////////////////// began to bud out, I re-grafted. Every graft was a success. This was the third year those particular plants (those clones that were root- connected and essentially the same plant) had failed, but then had 100 percent take when I used my method of turning on the hormone