Carrizo Rootstock for Citrus (CZ) (CZ0)

Carrizo: A Popular Citrus Rootstock with Nuances

Developed in 1909 by the USDA citrus breeding program in Riverside, California, Carrizo is a hybrid of Washington Navel orange and Poncirus trifoliata. Some debate surrounds its exact relationship to Troyer citrange, with some considering them identical despite separate clones being maintained. Regardless, their characteristics are very similar.

Carrizo offers several benefits. It promotes early fruit bearing in young trees, maintains excellent internal fruit quality, and typically results in medium to large fruit size. Additionally, Carrizo is a vigorous rootstock that encourages the development of medium to large trees, often considered the standard size.

However, Carrizo also has limitations. It is sensitive to chlorosis caused by alkaline soils. In some cases, iron and other trace element deficiencies on saline, calcareous, or high pH soils can lead to severe decline of Carrizo trees. Another potential drawback is an increased tendency for creasing. Carrizo can raise acidity levels, compared to rough lemon rootstock. 

t has occasionally caused issues with Valencia oranges, Minneola tangelos, and grapefruits grown in cooler regions. However it thrives in hotter climates.

Overall, Carrizo is a well-regarded rootstock for sweet oranges, grapefruits, and most mandarin hybrids, especially in the absence of severe disease or unfavorable soil conditions. Its key strengths include moderate resistance to Phytophthora root rot, tolerance to nematodes and Citrus tristeza virus (CTV), good internal fruit quality, earlier fruit color development compared to Swingle citrumelo, and promotion of medium-sized trees.

One important compatibility note: Carrizo is not suitable for use with Eureka lemons and other selections of the Eureka type.

Source:

• https://citrusrootstocks.org/wp-content/uploads/2020/03/Carrizo.pdf