Propagation Program Update on Donaldson and Other Trees

Josh McGill Florida Citrus Commission, Florida Department of Citrus, HLB Management

The Florida Citrus Commission (FCC) on June 14 received an update about a program for expedited propagation, in which 23 nurseries are participating. The goal of the expedited tree propagation program is to have several million HLB-tolerant or HLB-resistant trees planted in the next several years. Rosa Walsh, Florida Department of Citrus (FDOC) director of scientific research, provided the update. The FCC serves as the governing board for the FDOC.

Propagation Program
Florida citrus nurseries are working to ramp up production of HLB-tolerant trees. (Photo courtesy of Phillip Rucks Citrus Nursery)

Walsh reported that certified materials are in the increase tree stage, which means they are growing budwood in order to propagate field trees. As of June 14, there were approximately 700 increase Donaldson trees, 500 Parson Brown trees, 350 Carney 2 trees, 250 Carney 3 trees and 400 Roble trees. Nurseries are ready to take orders.

Walsh said these varieties will be included in the CRAFT (Citrus Research and Field Trial) program as well. The CRAFT program subsidizes growers who plant trees as part of research trials aimed at showing how well HLB mitigation strategies work in commercial groves. 

Some nurseries are waiting a little longer before beginning to bud Donaldson increase trees, Walsh reported. The Donaldson tree appears to be tolerant of HLB. A single Donaldson tree was discovered at the U.S. Department of Agriculture’s A.H. Whitmore Foundation Farm in July 2021. Old records indicated the tree was planted on Swingle rootstock. The first recorded mention of a Donaldson tree was in 1943 at the Hiawassee Farm in Orlando.

In order to garner more information on the Donaldson tree, 32 trees have been topworked with non-certified Donaldson buds, which are beginning to sprout. Additionally, there are 16 non-certified Donaldson trees, making 48 trees total, which have been planted in the field in three different areas, Walsh reported.

The expedited tree propagation program began in 2022; learn more about it here.

Source: FDOC

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