This topic might already be discussed sporadically throughout other threads but I’m not finding a clear answer to my question. Could be my searching skills though.
I’m curious about the concept of the juvenile phase, or the idea that there is a vegetative phase a seedling must go through before it’s even capable of flowering.
The part I’m not clear on is, can this juvenile phase be overcome by grafting? If a seedling has enough growth in the first year to make a usable scion, and I graft it the next spring to a precocious dwarfing rootstock, will it flower sooner than if I just let the seedling grow a few years before grafting?
I’m mostly interested in apples and pears right now, but would welcome feedback from those with experience growing other fruits from seed as well.
Yes, many plants such as apples and pears can take a long time until flowering from seed. But grafted/budded onto a more mature tree they may bloom next year. Routine with professional breeders.
On the flip side breeder’s such as Michurin found juvenile wood’s first blooms more receptive to foreign pollen so he regularly kept re-grafting a supply of his new clones juvenile wood for future pollination.
Two years ago I grafted Obilnaya scion to my mature cherry tree. Last year that scion had 14 fruits that would have fully ripened had a squirrel not climbed onto it breaking about half of its annual growth off. There is no way an Obilnaya seedling could achieve that in the first 2-3 years of growth! So the answer is very clear, a mature rootstock can provide the nutrients that a seedling cannot. This is why most nurseries developing new hybrids will graft new hybrids onto mature trees to test fruit quality.
Dennis
Kent, Wa
Dennis
Kent, Wa
I remember reading an article about apple seedlings reaching maturity. They found that the number of nodes between the roots and top of the tree seem to determine when it would flower. It was something like 110-120 nodes for most apples to flower. They grew trees in greenhouses to extend the growing season and pruned all side branches to promote growth in the central leader. They were able to get a number of apple seedlings to flower in their second leaf.
This is really interesting, thank you. I’m trying to collect all of the different viewpoints.
I searched on those key terms and found one of the articles discussing this affect.
It’s quite fascinating. They’re research was on Malus hupenhensis and their conclusion was “Young seedlings cannot be stimulated to flower by grafting onto older seedlings although older seedlings will continue to form flower buds after grafting onto young seedlings still in the juvenile phase.”
I started some seedlings from Jonagold apples. They are about 4 months old and have grown very well. I have a question about the growth on one particular seedling. These 3 seedlings came from the same apple and the apples were on dwarf rootstock the short seedling is just as healthy as the other 2 but the stem is quite a lot thicker, would this seedling be a natural dwarf seedling or can’t that happen? I was also told that triploid apples won’t germinate but these apples were definitely
Triploid apple trees cannot pollinate another tree, but they can be pollinated themselves by a compatible apple tree. So the seeds are capable of germinating because they were successfully pollinated.
And yes it is possible to get a seedling that is naturally dwarfing. That’s exactly what dwarf rootstocks are. Now I’m not sure how often that happens, or how long you would have to observe the tree before saying it’s a dwarf but it is technically possible. And you would probably have to clone it and start in a second location to prove it’s a dwarf because of its genetics, or if it’s just small because of it’s conditions.
I have one apple seedling that seems to be holding on to all of its leaves through winter. I see this trait in Oak trees on my property, but I’ve never noticed it with any of my apple trees. According to extension info this characteristic is called marcescence and besides Oaks and couple of other trees, it can also occasionally happen on any tree during juvenile growth.
One theory on marcescence is that it’s potentially a protective measure against cold and dry conditions. I thought that theory was interesting because this seedling was sprouted directly outdoors in pretty harsh conditions. It’s located in an especially dry area of my property, it was exposed to the elements all winter since I failed to get the area mulched, and we had one of our driest winters in memory with no measurable precipitation from December through February and no protective snow cover during that time. It was the only seed in that spot that sprouted, out of 15 or 20 seeds, and it sprouted a couple of weeks later than seedlings in my protected nursery.
None of the 25 apple seedlings sprouted in the nursery, which is much more protected and was well mulched all winter, held onto their leaves.
As I grow out more apple seedlings, I’m curious to see how common marcescence ends up being during the juvenile stage, and if that trait persists in this particular seedling. I would love to hear if any of you growing apple seedlings have paid attention to this trait. Is it common in apple seedlings during juvenile growth?
One thing you can do is to measure the intra nodal distances between the short one and the other seedlings. If the node spacing is significantly shorter then it may indicate the dwarfing trait genetics are in control as opposed to just a less vigorous root system, assuming all three were grown in the same growing conditions in similar potting medium and similar nutrients with equal sunlight exposure. Perhaps a mutation that naturally occured.
Dennis
Kent, Wa
According to SkillCult’s video, it doesn’t flower or fruit faster. He is using his mature apple tree as the host. He grafted a lot on it and doesn’t see a difference.
Personally, I grafted a few apple seedlings on a 7 - 8 year old apple tree from seed. The scions are from 1 year old seedlings. Only 1 scion stood out after 2 years. The scion grew faster, bigger, and taller than the original tree. This particular scion have a very tight leaves formation and produce more leaves than your average branch. The leaves produce energy for the roots and in turn, the roots sent a lot of water and nutrient to that branch. It didn’t flower, but the original tree did flower in the 3rd year, but no fruit. I expect the scion to be in the 3rd year next year and will flower too just like the original tree.
I agree with SkillCult that it doesn’t speed up the process. It may help the scion to grow faster and bigger. Grafting on a dwarf root stock may have a different outcome.
I have a Pink Lady apple tree. It’s a young tree. It doesn’t drop the leaves last winter. Guess, it didn’t sleep. It still produce its first apple in the summer. The chill hours doesn’t mean anything to that tree. I do get the 30’s and 40’s in winter.
I have found that it is pretty common in young apple seedlings to hold on to their leaves over their frost winters. All of them have lost that trait and get into a regularly timed leaf drop after two or three years. I think of it like calibration, it is as if the bio rhythm of the tree needs to fine tune to the seasons over a couple of years before it can properly anticipate them. It would make evolutionary sense for seedlings to have such a mechanism - read the local climate and timing in the place you were sprouted and than have a mechanism to adjust to it, rather than to be fully pre-programmed - that would make them a lot less likely to survive, since seeds are spread by animals and you never know where you will end up growing.
I think Michurin was probably correct. Research into florigen shows that flowering is initiated, at least in part, by changes in the shoot apical meristem. I have looked several times to see whether anyone has published work related to Michurin’s idea, but aside from his own non-scientific writings, I haven’t found anything. It would make an excellent graduate research project.
There is a small chance that Dr. Sax looked into this. The Arnold Arboretum contains a box entitled “Michurin Experiments” in Dr. Sax’s archive. Dr. Sax’s friend Nikolai Vavilov had just been murdered in the name of Michurin genetics/biology, so he—and the Western scientific community more broadly—was not particularly eager to publish studies that might validate Michurin’s ideas.
The grafts I have added to trees have not born fruit any sooner than just planting new trees. They just save money and room in the orchard, and offer an opportunity to grow more varieties to satisfy one’s curiosity.
Michurin also claims you can force old varieties that take forever to bear, like certain pears, to bear earlier by grafting seedlings approaching their first flower onto the crown of the old variety.
