Previously protected by Plant Patent #17863 which has since expired. Irradiation of budwood from registered “W. Murcott” trees in Lindcove, Calif. was accomplished in June, 1995 at Riverside using 50 Gray units of gamma irradiation from a Cobalt-60 irradiation source. Buds from this irradiation were propagated onto various rootstocks in the greenhouse at Riverside where they were grown to field-plantable-sized trees. These trees were planted in June 1996 at Riverside. Fruit production and evaluation began in 1998. One tree from this irradiated population (propagated on ‘C32’ citrange rootstock) distinguished itself from the others in having fruit that had very low seed counts with excellent fruit quality and normal fruit production characteristics in comparison to the original ‘W. Murcott’ cultivar. After two seasons of fruiting, this tree (now named ‘Tango’). Fruit of 'Tango' are similiar to W. Murcott in all appearance, quality and production characteristics with the exception of seed numbers. 'Tango' fruit are deeply oblate in shape with no neck. The fruit is medium sized for a mandarin (classed as Large by State of California standards and size 28 by industry packing standards) averaging 59 mm (2.32 in.) in diameter and 48 mm (1.89 in.) in height with a very smooth, deep orange rind color. The rind is relatively thin and at maturity is easy to peel. The fruit interior has fine flesh texture with 9-10 segments and a semi-hollow axis of medium size at maturity. Fruit are very easy to peel. The fruit are juicy averaging slightly over 50% juice with an average weight of 90.6g (3.2 oz.). Tango matures in winter (late January) and holds its fruit quality characteristics through April into May. Production is excellent averaging 800-900 cartons/acre when planted at densities of 250-300 trees/acre. Fruit from trees on Carrizo and C-35 citrange rootstocks average 11.1-13.1% soluble solids and 0.97-1.19% acid in January increasing to 13.5-15.4% soluble solids with decreasing acid of 0.54-0.82% in April. 'Tango' averages from 0.04 - 0.2 seeds per fruit in the presence of cross-pollination at seven trial locations throughout California compared to 11.6-22.6 seeds per fruit for W. Murcott. Pollen of 'Tango' has very low viability consequently it has a very low likelihood of causing seeds in other citrus, particularly mandarins, when planted nearby. Like W. Murcott, trees of 'Tango' have a tendency to overbear and therefore need to be regularly pruned to maintain good, not excessive production and to maintain fruit size and prevent alternate bearing. Crop yields should be limited to about 150-170 lbs/tree (6-7 mandarin boxes) through a combination of pruning and, if needed, fruit thinning and should be harvested on time, not left on the trees as this can lead to alternate bearing. Extensive information is available in both the patent and UCR page for this variety.