- Author: Therese Kapaun
It's harvest time in the San Joaquin Valley for early navel varieties, and the great tasting Fukumoto could also win a navel beauty contest. The Fukumoto variety attains a deep orange peel color, is relatively spherical in shape, and has a smooth rind. Fukumotos reach legal maturity (a minimum score of 90 for the California Standard) in October or November in this region.
The Fukumoto block at LREC was planted in 2005, and has more than 100 trees on each of three rootstocks. Dr. Mikeal Roose (UC Riverside) is studying scion and rootstock compatibility, canopy size, yield, and many fruit quality parameters. The project utilizes the LREC packline for size, color, yield, and granulation data, and the LREC fruit quality laboratory for texture, °Brix, percent juice, and rind thickness data.
Come taste the fabulous Fukumoto navel later this month at Lindcove's Annual Fruit Display and Tasting. Watch this space for more information about the two day event. More information about the Fukumoto navel can be found at http://www.citrusvariety.ucr.edu/citrus/fukumoto.html
Occasionally a single limb of a citrus tree produces unusual fruit that looks or tastes different than fruit on the rest of the tree. This is caused by a spontaneous mutation in the cell lines of the limb, which causes a natural modification in gene expression, and is known as a budsport. Many traits such as color and texture of the rind, color and flavor of the fruit, maturity date, season of flowering, and seediness can be altered as a result of a mutation.
Most citrus cultivars arise this way. A classic example is the navel orange, which we know of as being seedless and having a small conjoined twin (the navel) at it's base. This unusual fruit was discovered nearly 200 years ago from a sweet orange tree in Brazil that did not have these traits. In the late 1800's budwood from this tree was sent to the US, propagated onto rootstocks, and widely planted in California. Since then, clonal propagations of this 'Parent' navel have resulted in more budsports, and there are now more than 60 navel orange cultivars in the Citrus Variety Collection at UC Riverside. A popular 'Parent' navel budsport is the 'Cara Cara' navel, with pink flesh and an earlier ripening date, and from the 'Cara Cara' came the 'Variegated Cara Cara', with pink flesh and a striped rind.
Citrus Clonal Protection Program Staff Research Associate Rock Christiano firstname.lastname@example.org welcomes growers and individuals who have, or think they have, discovered a budsport to learn about how to develop it into a novel citrus variety. The choice of what to name it is usually left to the grower who discovered it! More information is available at http://ccpp.ucr.edu/
These photos show fruit on a limb of 'Frost Owari' satsuma which is distinctly different than the fruit on the rest of the tree. This budsport limb, recently photographed near Exeter CA, produced fruit that is smoother in rind texture, more vibrant in color, higher in °Brix, and lower in acidity than the rest of the fruit on the tree. The fruit on that limb is maturing sooner than the rest of the tree and could potentially produce a new 'Early Owari' variety.
Autumn has arrived, and many of the early varieties of satsuma are starting to taste good. October's cool nights induce the rinds to gain color, and rinds are getting easier to peel. Lindcove REC has more than 40 satsuma varieties, and early season favorites include 'Xie Shan', 'Miyagawa', 'China S-9', 'Miho Wase', 'Okitsu Wase', 'China S-1', and 'China S-5'.
Dr. Tracy Kahn (UC Riverside, Dept. of Botany and Plant Sciences), recently published an informative article in Citrograph, entitled "Fruit quality evaluations of introduced Satsuma selections for California" in the March/April 2013 edition. In addition to fruit quality data, the article describes the origin of the satsuma, genesis of nucellar selections, and introduction of satsuma varieties to the US. Click on this link to view the magazine, the article begins on page 34. http://www.citrusresearch.org/citrograph_marapr2013-2
Dr. Kahn will be giving a tour "Evaluation of early citrus varieties" at Lindcove REC on November 12th at 10 am.
- Author: Elizabeth E Grafton-Cardwell
It is hard to see the sun rise in the mornings the smoke haze is so dense in the central San Joaquin Valley. Normally at Lindcove REC, I can see majestic mountains behind the foothills but lately they have been obscured by smoke. We are all hoping that the fire will be extinguished soon.
Claire Federici (UC Riverside, Dept. of Botany and Plant Sciences) examines Olinda Valencia oranges, hoping to locate seedless fruit. This group of Valencia trees are part of a long-running plant breeding project at Lindcove that is headed by Dr. Mikeal Roose, and is the same project that has brought low-seeded mandarins to global markets. The Valencia trees were grown from irradiated budwood, which has the intended result of occasionally disrupting the genes that promote seed formation. If a tree is found to have low-seeded fruit, then its budwood is likely to produce low-seeded fruit, and a new low-seeded line of Olinda is created!
While several varieties of seedless or low-seeded Valencias are commercially available, notably Delta and Midknight, the popular seedy Olinda variety is favored by San Joaquin Valley growers for high productivity and tolerance of hot summers.