How can I encourage citrus trees to fruit earlier in their life? Due to biosecurity concerns, I am unable to obtain mature scion wood for some citrus varieties I want to grow. However, I can obtain polyembryonic seeds that I think will grow true.

If I graft the desired variety onto regular 6-9 month old rootstocks, I expect to wait 5-7 years until fruiting. Is there any way to accelerate this?

One person suggested grafting my immature scions onto a dwarfing rootstock, or the rootstock from a mature tree. Another person suggested grafting onto Macrophylla rootstock. With any of these work?

I don't have access to dwarfing rootstock or Macrophylla rootstock, but can graft onto mature trees if this will accelerate fruiting.

Any ideas or comments on the above suggestions would be appreciated!

Thanks,
John

Firstly what Citrus do you want to grow? Some types will take a long time to fruit from seed, but others could be shorter than 7 years. As you are in Fiji, you should get rapid growth of seedlings, so the waiting time will probably be less( are there highland areas which are cooler/ less tropical?)
The key to getting Citrus seedlings to fruit is getting them to full size trees as quickly as possible.
On this forum there have been several discussions of "node count" , which is a measure of tree size at first fruiting.
Grafting onto mature trees, onto dwarfing stock etc doesn't reliably work with all Citrus cultivars as it does with other fruit species.
It has been said to work in some cases/some cultivars, but doesn't seem a universal method.
Grafting onto a stock or tree that can push the growth of your seedling scion as fast as possible, or faster than the original seedling is capable is more likely to work.
Macrophylla is a vigorous lemon type stock, which is going to push your scion faster than others. You may do as well with local Citrus types such as pummelo or rough lemon as rootstocks, if they do well under local conditions.

Thank you, pagnr, for your reply.

I am growing Rio Star grapefruit from seed, and also want to grow blood orange from seed, as I can not obtain mature scion wood for those in Fiji.

Citrus does grow fast here. If I want to speed it up more, is seems from your input and what I've heard elsewher the best I can do is to graft the immature scion wood onto some more mature rough lemon and sour orange so the roots push plenty of sap for growth flushes in the scion wood.

My small farm is coastal, which may be better for citrus growth, but problematic for growing the sweetest oranges or yellowing of the fruit.

I'm new to growing citrus. Started grafting about 2 years ago and planting last year.



John

A friend grew seedling grapefruit(Balinese) in Cairns region QLD. That tree was 5 or 6 m tall and fruiting in 4 years. Blood orange may like more cold than it can get in Fiji to get good pigmented fruit? Red grapefruit require heat to develop color( They both DON'T have the same red pigment )
Rough lemon rootstock is said to make the scion fruit a little sour, doesn't matter with limes and lemons, some say it affects sweet fruit cultivars.
What types of local Citrus are growing in Fiji??

John, looks like a great place to live. I agree, I doubt you will get much "blood" coloring in a tropical environment.

The nice part about a tropical environment is that you have a endless growing season. I have two grapefruit trees I grew from seed six years ago & both are producing excellent crops of fruit now. I would think in your location most varieties of citrus will fruit rather quickly from seed.

Approximately 98% of the citrus sold in local markets are rough lemon and sour orange. Every village has them. There are also some pomelo with an extremely thick skin, maybe 5 cm (2") thick, and a small bitter grapefruit sized fruit inside.

The agriculture department has introduced meyer lemon, seedless tahitian lime, satsuma mandarin, a round kumquat, and a valencia and navel orange. They are not yet widely distributed.

The Ag department grafts everything onto rough lemon rootstock, but I'm growing some sour orange rootstock now for the oranges, some grapefruit and mandarin.

In a year or two I plan to raise a lot of extra young trees to sell and gift, as I am sure demand for these varieties will be strong.

Right now, my first batch of trees are still small, mostly meyer lemon and seedless lime, as I don't yet have sour orange rootstocks ready.

John

Both Meyer lemon & lime are very easy to root & do great on their own roots.

Personally, I would never use rough lemon as a rootstock for any sweet citrus variety. Rough lemon generally produces inferior fruit, when sweet citrus varieties are grafted upon it. - Millet (365 ABO-)

Laaz, I hope I didn't completely waste my time grafting meyer lemon and seedless lime on rough lemon rootstock. Before I started grafting, I rooted several lemon and lime cuttings and they are doing fine. However, the Ag guy I spoke to thought the rough lemon rootstock would do better in times of drought. Do you think that's right?

Do you guys think the blood orange in a tropical environment will be 'bloody' enough to differentiate it from the yellow/orange oranges?

Here's another shot of the area I am planting (the brown grass area near the sea; next rainy season I will also plant various fruit trees up the hill).



By the way, I have seen old rough lemon trees growing right by the ocean, so I'm pretty sure that won't be a problem on my farm. I'm on the leeward side of the island for the prevailing winds, but a cyclone wind can of course be from any direction.

John

jcaldeira, Sour Orange is a really great rootstock as long as your area is not infected with the tristeza virus. Sour Orange rootstock is good against soil salinity, high pH, clay soil, freezes, and extra good against wet soils. However it is susceptible to burrowing nematodes and citrus nematodes, but tolerant to foot and root rot, xyloporosis viroid, exocortis viroid, and extra tolerant against blight. The rootstock's big problem is the tristeza virus, but if the Fiji Islands is not infected with the virus, Sour Orange will be an excellent rootstock. It produces an intermediate to a large size tree, with high yields of intermediate sized fruit. - Millet (366 ABO-)

The advantage of rough lemon is that it is very well adapted to sub tropical and tropical areas with a dry spell. It probably grows wild in Fiji, as it does in similar parts of Australia. Lemons and limes will be great on RL, how more sour much can they get.
See if your Ag guy can locate some oranges or mandarins grafted on RL, and see what the fruit quality is like.
Red pummelo is probably a better choice than red grapefruit.
Cara cara(red)navel is orange probably better than Blood.

Thanks for all the information and suggestions.

The Ag guys I spoke with didn't know anything about tristiza. There are so many sour orange trees here that I'm confident they'll do well.

I've tasted valencia and navel oranges that the Ag folks grafted on rough lemon. Both were bland. Not sour, but bland. I'm hoping it's the rootstock causing the blandness, which should make the fruit from my oranges on sour orange rootstocks really stand out.

John

Maybe this helps:

Rootstocks recommended for citrus fruits
in Hawaii.:

http://www.ctahr.hawaii.edu/oc/freepubs/pdf/RES-053.pdf