C. ryukyuensis sp. Diversification of mandarin citrus by hyb

[sanguinho]

www.nature.com/articles/s41467-021-24653-0

[jibro]

Thanks for this article, there is interesting information about Yuzu origin:

For example, we find that Yuzu, cultivated for its pleasing flavor and aroma valued in gastronomy and aromatherapy, is an F1 hybrid of mangshanyeju with an Ichang papeda seed parent (Supplementary Note 8). We caution that “mangshanyeju” should not be confused with ‘mangshanyegan’ (wild citrus (‘gan’) from Mangshan, C. mangshanensis), which is a distantly related citrus species from the same region.Yuzu’s unique mangshanyeju ancestry might be explained by the fact that wild Ichang papeda are
found grown in sympatry with mangshanyeju 49 . This would imply Mangshan region as the
original birthplace of yuzu. Presumably, the inherited apomixis trait from mangshanyeju and
cold-hardiness trait from Ichang papeda allow the clonal propagation of yuzu into much wider
geographical areas and variable clima

Keraji and Kabuchii - pdf page 27

static-content.springer.com/esm/art%3A10.1038%2Fs41467-021-24653-0/MediaObjects/41467_2021_24653_MOESM1_ESM.pdf

Three members of this family are half-sibs that have been classically referred to as different
species 43 : oto ( C. oto hort. ex Yu. Tanaka), kabuchii ( C. keraji var. kabuchii hort. ex Tanaka), and
tarogayo ( C. tarogayo hort. ex Tanaka). The parent-child relationship between kunenbo and
kabuchii was previously noted 19 .

A fourth type related to kunenbo, keraji-mikan, is a backcross of kabuchii to kunenbo as
previously noted. 19 and now confirmed by our genomic analysis. Since both have the same
cpDNA, we cannot determine which is the maternal parent. Keraji-mikan has also been assigned
taxonomically to C. keraji , although Yamamoto and colleagues recognized that kabuchii and
keraji-mikan are distinct both phenotypically and with molecular markers 44 . Yamamoto et al.
differentiate between keraji-type, a nearly seedless type with smooth rind, and 'kabuchii-type'
that is seedy with rough rind.The seven members of this family inherited the polyembryonic allele from their kunenbo seed
parent (itself being heterozygous for this allele), with keraji-mikan being homozygous for this
allele as a result of the backcross.  All seven accessions are inferred to be polyembryonic and
inherit the sweet orange cpDNA type from kunenbo

[steffengot]

Very interesting publication.
Especially since the relation between the citrus from the ryukyu islands are explained in detail.

I however wonder if the citrus were just a random found or if there are more trees in the wild.

In 2019 I was also on the Ryukyu Islands and remember that I saw a wild citrus trees on one of the smaller islands in the bushes. I however could not see fruits on the tree and due to toxic spiders and snakes and did not walk trough the brush. I always thought this might me a wild Shikuwasa or Tachibana. Now I wonder even more what species/hybrid that was.

[millet]

My guess is that none of these varieties are not cultivated to any extent.  I lived on the Ryukyu islands (Okinawa) for two years and never seen a citrus tree of any kind. 

[steffengot]

It’s pretty surprising, because Shukuwasa is extensively grown in the norther part of the main island (Okinawa). The fruits are sold everywhere on the island in different degrees of maturity.
I just wonder how common it is to find the named C. ryukyuensis. Apparently C. ryukyuensis is monoembrionic, while Shikuwasa is polyembrionic and it was more by chance that it was found.

[millet]

Jul 28, 2021 10:51:23 GMT -5 millet said:

Stefferngot, that is possible because the vast majority of the population lives in the central and south portion of Okinawa 

[pagnr]

Here is a C. ryukyuensis fruit
www.thepacker.com/news/produce-crops/back-future-citrus-breeders-look-ancient-varieties-modern-day-answers

and an interesting related article from Okinawa Institute
www.oist.jp/news-center/press-releases/juicy-past-favorite-okinawan-fruit-revealed

[steffengot]

Indeed very interesting articles.

Would be nice to have the contact to the local farmer Hiroshi Kobashigawa. He grows Shikuwasa and has apparently some citrus ryukyuensis growing on his farm.

[pagnr]

Kobashigawa Hiroshi, farmer seen here and further down under Tasting Local Citrus, 
guide.michelin.com/sg/en/article/features/discover-okinawa-ingredient-akira-back-singapore-tomoyuki-kiga

[steffengot]

Yeah I also found that article.
But could be nice to have an email adress or to know where his farm in Ogimi is.

[pagnr]

"Citrus Genetic Resources Grown on the Ryukyu Islands, Japan"
Not up to date, but has images of some of the other Okinawan types mentioned as the yukunibu group.
core.ac.uk/download/pdf/144573096.

[Sylvain]

core.ac.uk/download/pdf/144573096.pdf

[radoslav]

I grow a bunch of citrus tarogayo seedlings, they are also from Okinawa.

[pagnr]

One of the articles I saw mentioned that some of the Okinawa Citrus sampled came from a private collection in Okinawa.
I wonder if any members have ever heard of Citrus collectors or hobbyists in Japan ??

[Sylvain]

we find that Yuzu ... is an F1 hybrid of mangshanyeju with an Ichang papeda seed parent.

It is at odds with www.researchgate.net/publication/311245868/figure/fig8/AS:434504478269440@1480605348500/An-inferred-genealogy-of-citrus-indigenous-varieties-part-1-The-plot-shows-the.png that says that C.inchangensis (Ichanshii) doesn't share the same cytoplasm, indicated by the color, than yuzu.

Then C.inchangensis  cannot be the seed parent of yuzu.