What to use - seed grown citrus as rootstock?

Question

I have been growing a "clementine tree" from seed for about three years now and decided that I might want to experiment with some grafting onto it. So, I went away to try and went way overboard (as is usual). I planted store bought citrus seeds from all of the following in addition to the single clementine plant. I now have at least five seedlings of each below to experiment with:

1 Key lime seedlings

2 Kumquat seedlings (Nagami)

3 Blood orange seedlings

4 Lemon seedlings

I did not want to use grapefruit because of the much larger fruit and long maturation time. My questions now mostly involve "what kind" to graft onto "what kind" for a reasonably good result. What kind might be best for the root stock? Can I graft three or four of these together successfully? I was thinking Lemon/Key lime/Kumquat/clementine together etc. but, I then noticed how many differences there were between the seedlings (vigor, size, and speed of growth). I think I also read that Key limes and Kumquats grow true from seed and bear fruit sooner. Can anyone advise about potential best grafting combination(s)?

I live in the Northeast and will be growing potted plants indoors/outdoors as the seasons permit.

Answer 1

You usually graft from an existing, fruit-producing tree onto rootstock. You don't typically graft a seed-grown tree onto another seed-grown tree. Grafting "budwood" from a producing tree onto rootstock provides two benefits: 1) the new tree immediately starts producing fruit, thereby skipping the 3 to 7 year juvenile stage where the tree does not produce fruit, and 2) the new tree produces fruit with known, desirable characteristics, since you have essentially cloned the budwood onto a new tree. Growing feom seed, you are getting the offspring of two different trees, and the new tree may not produce the same fruit from which the seed came. It may have minor genetic diffrerences, or it may be an entirely new hybrid. Finally, back to 1 above, the grafted budwood from the nee seedling may still take 3 to 7 years to priduce. Additionally, grafting budwood from a tree that is not certified as disease free may inadvertantly cause the spread of devastating citrus viruses. For this reason it is better to buy certified disease-free budwood of a known, desirable variety for grafting. Or, at the very least, graft from known, producing tree (if you live in an area that is not susciotible to any of the viruses).