Citrumelo ‘Swingle 4475’
Swingle Citrumelo Citrumelo
4475, Citrumelo, CP4475, CP4475 4n, CPB 4475, CPB-4475, CRC 4475, SW 4475, Swingle 4475
It’s a hybrid of grapefruit 'Duncan' and Poncirus bred in 1907 in Florida by Dr. Walter Tennyson Swingle (the citrumelo carries his name in honor of his work) that was officially released only in 1974.
This deciduous tree is medium high with many wide branches and covered with normal sized trifoliate leaves. Its yields are very high, but the tree is less hardy, than the citranges. However some sources state that the hardiness of this particular citrumelo could be somewhere close to -15°C. Citrumelo ‘Swingle 4475’ is not sensitive on tristesa, exocrtis, xyloporosis, root rotting or nematodes. It stands well to overwatering, but dislikes too high soil salinization and high soil pH.
The fruit is medium sized (6,5-7,5 cm) with average weight 120 g. Its shape is elliptic or similar to that of pears; it has a ridge at the base. The rind is dark yellow, slightly pebbled, rough and about 9-10 mm thick. The pulp is amber yellow to light orange with soft, juicy and acidic taste and resin aroma. Each fruit has approximately 9-10 segments and few seeds.
It is an exceptionally good rootstock for grapefruit, that’s why it was spread so fast in the past. Grafted citruses are fruiting as well and with such a quality, as if they were grafted on ‘Troyer’, ‘Carrizo’ or Citrus aurantium. Slight difference is in ripening of the fruit, when the citruses grafted on ‘Swingle 4475’ start getting the right ripe color later, than with other rootstocks. The orange variety 'Valencia' reaches only smaller heights and has smaller fruit than on the other rootstocks, another incompatibility is said to be with the tangor 'Murcott' and orange variety 'Roble'. Also the lemon graft of variety ‘Eureka’ doesn’t grow well. Regarding the grapefruit and shedok, fruit quality of grafted citruses is excellent. This citrumelo is not adviced for tangerines and their hybrids because of the incompatibility. It isn’t popular rootstock in Mediterranean or Israel.