History

Cross Made

Washington navel orange was crossed with trifoliate orange in 1909 by E. M. Savage under W. T. Swingle’s direction at the U.S. Department of Agriculture; Hodgson (1967) reports that Savage and Gardner’s later study identified the resulting zygotic seedling CPB 4-5019 as the same clone known as Carrizo and Troyer.

• E. M. SavageBreeder

  Made the Washington navel orange × trifoliate orange cross that produced the zygotic seedling CPB 4-5019, later known as Troyer and Carrizo citrange.

• Walter T. SwingleDeveloper

  Directed the USDA breeding work under which E. M. Savage produced the original hybrid.

• United States Department of AgricultureDeveloper

  Conducted the breeding program through which CPB 4-5019 was produced and subsequently evaluated and distributed.

Sources: ⁠[17]

Named

W. T. Swingle assigned the name ‘Troyer’ to the CPB 4-5019 citrange clone in 1934, as reported by Hodgson (1967).

• Walter T. SwingleNamer

  Assigned the name ‘Troyer’ to the CPB 4-5019 citrange clone in 1934.

Sources: ⁠[17]

Released

The Citrus Rootstocks index lists the USDA release date of Carrizo Citrange as 1938.

Sources: ⁠[7]

Other

Hodgson (1967) reports that Savage and Gardner presented evidence in 1965 that Carrizo and Troyer were not sister seedlings but the same zygotic clone, CPB 4-5019, from the 1909 Washington navel × trifoliate orange cross.

• E. M. SavageOther

  Co-published evidence that Carrizo and Troyer originated from the same zygotic seedling, CPB 4-5019, rather than being sister seedlings.

• Frank E. GardnerOther

  Co-published evidence that Carrizo and Troyer were the same clone.

Sources: ⁠[17]

Introduced

Two historical accounts describe transfers of Carrizo material differently. Hodgson’s 1967 account reports that 200 seedlings of the then-unnamed clone were sent to Winter Haven Substation No. 19 near Carrizo Springs in 1923. UCR reproduces a July 1959 letter by W. C. Cooper quoting E. Mortensen’s recollection of about 200 seeds sent to Mortensen in 1930 as CPB 450198-B. These accounts differ in year, propagule form, and code; the available records do not establish whether they describe the same transfer.

• Walter T. SwingleIntroducer

  Hodgson attributes the reported 1923 shipment of 200 unnamed seedlings to Walter T. Swingle; Cooper’s letter separately reports Mortensen’s recollection of a 1930 seed shipment. This credit records the attributed transfer accounts.

Sources: ⁠[1]⁠[17]