US-1283 Citrandarin

US-1283 is a USDA citrandarin from a 1995 Ninkat mandarin × Gotha Road #6 trifoliate orange cross. It was released in September 2014 as a citrus rootstock.^⁠[2]⁠[7]

Hamlin orange trees on US-1283 outyielded Swingle in a Florida flatwoods trial affected by HLB. The advantage was less clear at a separate ridge site; the flatwoods result reflects tolerance after infection rather than resistance to infection.^⁠[2]⁠[7]

Graft compatibility requires care. A 2020 notice reported nursery problems with Star Ruby grapefruit, Bearss lemon, and Tango mandarin. A later greenhouse study found stem grooving and bark necrosis with Bearss lemon and Valencia orange on one US-1283 source, while the same scions on US-812 formed normal unions. These observations do not establish a rule for every US-1283 tree or scion.^⁠[5]⁠[4]

A 2020 nursery study reported 98% emergence from 294 planted US-1283 seeds, with 91% of seedlings visually classified as true-to-type. This supports seed-propagation potential, but the results concern one open-pollinated seed collection; the separate DNA-marker check used a selected subset.^⁠[6]