Carrizo is likely the single most important rootstock in the US citrus industry. Since 1970, 27.5% of Florida citrus, amounting to 39.5 million trees, have been propagated on Carrizo rootstock. It is widely accepted that Carrizo (in combination with the identical hybrid Troyer) is also the most widely planted California citrus rootstock.
   Carrizo (Troyer) is a hybrid from a 'Washington' navel orange x Poncirus trifoliata cross (Hodgson, 1967). Poncirus is a common source of resistance or tolerance to both biotic and abiotic stresses (cold, diseases and pests). Especially noteworthy is the high degree of huanglongbing tolerance reported for Poncirus and its hybrid Carrizo (Folimonova et al., 2009). Huanglongbing is considered to be the most serious threat to citrus worldwide, is now widespread in Florida, and threatens California, Texas and other US citrus growing areas. Availability of Carrizo sequence data may provide researchers the key to developing haunglongbing resistance, through conventional breeding or biotechnology.

Disclaimer The Public Citrus Genome Database is made freely available to the citrus research community with no limits on its dissemination. Use of this sequence is not limited by the Fort Lauderdale agreement.

Hodgson, R.W. 1967. Horticultural varieties of Citrus. In W. Reuther, H.J. Webber, and L.D. Batchelor, eds., The Citrus Industry, vol. 1, pp. 431-591. University of California, Berkeley
Folimonova, S.Y., Robertson, C.J, Garnsey, S.M., Gowda, S. and Dawson, W.O. 2009. Examination of the responses of different genotypes of citrus to huanglongbing (citrus greening) under different conditions. Phytopath. 99:1346-1354.