FYI TANGO MANDARIN WILL BE INCLUDED IN THE CCPP "EARLY RELEASE" FOR JUNE 2007 02/27/07

W. Murcott Afourer mandarin (VI 462) is the variety source of the irradiated variety Tango.

W. Murcott Afourer was received into quarantine at CCPP from Morocco via USDA-APHIS in June 1985. Under CCPP protocol all foreign imports undergo either thermaltherapy or Shoot-tip-micrografting, or both, as a precaution against new or unknown pathogens which might not be detected during indexing. In January of 1986 VI 462 W. Murcott Afourer entered thermaltherapy # 1721 at CCPP Rubidoux. Thermaltherapy on this variety was completed in June 1986. In August 1987 VI 462 (Source Thermaltherapy # 1721-10) entered final testing in the VI Index at CCPP. In the VI Index this variety tested free of known bud transmissible pathogens.

In February of 1988 two trees of VI 462 were budded at CCPP under quarantine. USDA-APHIS and CDFA quarantine releases were granted to CCPP for release of VI 462 in February of 1989 based on the completed testing.

In May of 1989 the two trees of VI 462 were moved from quarantine at CCPP Riverside to the Lindcove Research and Extension Center and were planted in the CCPP Foundation Block. Very little was known about the variety or how it would perform under California conditions at this time. After 3 seasons of fruit and tree evaluation the two trees of VI 462 were registered with CDFA in 1992 and budwood distribution began.

From the time that these two trees were registered in 1992 to present, they have been annually retested for tristeza and vein enation by graft inoculation to Mexican Lime. Additionally these trees have been tested up to four more times per year during this period by ELISA for the presence of tristeza virus. Registered trees are also retested each third year for the presence of citrus viroids by sPAGE and each fifth year for the presence of citrus Psorosis and related pathogens by inoculation to sweet orange and Dweet tangor.

In 2002 buds were cut from the registered trees in the CCPP Foundation Block at Lindcove REC and were moved to the lab of Dr. Mikeal Roose, Dept. of Botany & Plant Sciences, at the University of California, Riverside, for irradiation. During the year 2003 irradiated buds of VI 462 were moved by Dr. Roose from UC Riverside back to the Lindcove REC and were topworked onto an existing tree located at LREC in field 13. The irradiated variety was renamed Tango by Dr. Roose.

In December of 2005 budwood was harvested from the topworked tree in field 13 at Lindcove REC and moved back into quarantine at CCPP for retesting and propagation. Because the buds were taken from a topworked tree outside the CCPP Foundation Block, the CCPP elected to fully retest the variety to ensure that it is still free of bud transmissible pathogens. This variety completed the VI Index at CCPP as VI 746C, Tango Mandarin, in July 2006. USDA-APHIS and CDFA quarantine release was granted for VI 746C in September of 2006.

Field propagations were made at CCPP and will be planted in the CCPP Lindcove Foundation Block in the spring of 2007. Several “Early Release” propagations were also made at this time and these potted propagations have completed testing for CDFA Registration. The first CCPP Foundation budwood distribution of VI 746C, Tango Mandarin, is scheduled for June 2007. This June 2007 initial CCPP release of VI 746C will be under the conditional “Early Release” program and a maximum of 12 buds per order will be available to each participating nursery or grower