Citrus greening resistant variety on traditional rootstock

[daisyguy]

I live in Florida and I was thinking about buying a Sugar Belle mandarin because they supposedly have displayed some resistance to citrus greening disease. But, the Sugar Belles I've seen for sale are grafted onto Trifoliate or Sour Orange rootstook. Wouldn't greening travel to the rootstock and from there bottleneck the rest of the tree?

[daisyguy]

While I'd appreciate any additional feedback you all have, I did find an article that addresses my question: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=43143

Grosser says it has become evident from multiple trials that Sugar Belle has exceptional HLB tolerance no matter what rootstock it is grown on.

The article mentions that resistant rootstocks confer some resistance to the scions:

According to Grosser, the Alligator Grove has never had psyllid control, and about four years after planting, it was evident that nearly all the trees were infected with HLB. “For the past six years, I have been scoring the individual trees for HLB. There were only two of the trees on the S13 parent (salt tolerant HB pummelo x Cleo). During the 2020 scoring, this hybrid had the highest tree health rating (4.25 out of 5), indicating very good ability to transmit HLB tolerance from the rootstock to the Valencia scion,”

[Galatians522]

Both sour orange and trifoliate hybrids (such as a swingle) are more greening resistant. I saw a lot of growers going back to sour orange after greening even with the trestezia risk. There are rootstocks that are even more tollerent than Sugarbell, though.

[Citradia]

Daisyguy, since you’re in Gainesville, you will benefit from the extra cold resistance from the trifoliate rootstock anyway. Sugarbell and trifoliata are both resistant and sugar Belle is cold hardy. Go for it.

[pagnr]

In other virus  cases I have heard of the rootstock gets infected by rootstock shoots or suckers and if these are prevented infection is less likely if the scion is resistant. Not sure if that applies across the board.

[poncirsguy]

Are Meiwa and Fukushu kumquats affected by greening.  They are Fortunella not citrus.

[Galatians522]

Are Meiwa and Fukushu kumquats affected by greening.  They are Fortunella not citrus.

Yes, they get greening. Last time I went to the Kumquat festival in Dade City the old groves there were pretty sad looking--nothing like I remembered them as a kid.

[1rainman]

We have sugar bell. It is more vigorous than most. Still a baby. Unharmed by a hurricane. Appears disease free but not nearly as healthy as swingle and sour orange. Even sugar bell has some small suceptibility. Swingle, trifoliate etc has zero disease basically.

There is a wild orange that is edible growing in the park. Not the greatest tasting but edible. It's sweet not sour barely noticeable off taste maybe some trifoliate in it's background. It has been there as long as I remember grew from a seed. Full of seeds. It is totally disease resistant. Maybe it's some kind of hybrid. I might get seeds if I have a chance.

They should cross a Dunstan grapefruit with a really good red grapefruit maybe get a good disease resistant cold hardy grapefruit.

There was another ugli fruit looking type of orange growing wild again edible but not great but totally different from the first one. Was a field of them in the park but they cut them down. Totally disease and cold resistant. There was also a really good grapefruit tree growing wild. It all might be gone now.

[1rainman]

Here is a version of seeds reverting to wild but I was told on here that doesn't happen. So maybe this crossed with some kind of root stock like swingle.

This tree grew from a seed. Someone ate an orange and spit the seeds out 20 years ago. The tree is healthy while others in the area fade from greening or similar viruses. Tree and leaf looks like an orange. Oranges are full of seeds. Like 100 seeds inside which is the biggest negative. Orange looks normal on the outside. Tastes sweet, good flavor. Very slight trifoliate off flavor. But to put in perspective people pick these and eat them. They are less good than normal oranges but good. Tree is not thorny. Tall shade tree like which is how citrus grows from seed where they are shorter and bushier from cuttings.

I snagged some seeds off an unripe fruit today. Since everyone picks them they are hard to.get.

[pagnr]

I snagged some seeds off an unripe fruit today. Since everyone picks them they are hard to.get.

Some pics of fruit and seed would be great, looks interesting.

[1rainman]

There's one green not even half ripe fruit. I found one that was damaged or something but seeds appeared ripe. Seeds are skinny compared to normal. It looks exactly like a typical orange.

[1rainman]

I would imagine you could get all sorts of different orange seeds or tangelos and such and plant about 200 you would probably end up with a disease resistant one. That's what happens in the woods. Only the strong survive. Besides that they seem stronger from seed generally than grafted or rooted. But they keep tearing down the woods and building stuff.

Unfortunately I have found what appear to be beautiful orange trees and bit into them and they taste like a lemon. Sour orange. I also rarely see citrus in people's yards anymore. The virus wiped them out.

This variety I found in the park would be good to cross with sugar bell in an attempt to improve the quality while maintaining disease resistance. Even not considering disease it's growing well in the woods which is tough. They cut it back a lot to keep it off the trail. I will look if any of the other disease resistant variety are still around in the parks. They cut everything down. Same wild my wild grapes growing in the park they cut them back a few years ago.

[1rainman]

I found a whole field of the second type. No fruit. Maybe wrong time of year maybe not old enough though there were a few large trees. I suspect this is a cross of sour orange with grapefruit maybe something else. The ones they cut down that had fruit were slightly sour but not extremely so. You could eat them but not great. Few seeds no trifoliate flavor. Disease resistant obviously. I would rate them about the same sourness as a grapefruit but with orange flavor and smell. Fruit looks like ugli fruit but a bit smaller. leaves smell like an orange. I would guess it could be a tangelo crossed with a sour orange. Though it has bred with itself to produce the fields of trees.