U.S. Department of Agriculture's Agricultural Research Service scientists in Fort Pierce, Florida, are assessing the possibility of the Donaldson orange variety replacing the HLB-ravaged Hamlin in orange juice. 

Researchers conducted taste tests to study the differences between OJ blends using Hamlin and Donaldson oranges and found that taste testers noted that there was a difference between the two juices.

However, researcher Matt Mattia, USDA-ARS research geneticist, said that "those differences may be explained by the lower acidity in fruits from young Hamlin trees.” 

The variety was discovered by ARS scientists while assessing citrus trees to find out what oranges could be potentially used for commercial production of orange juice. The Donaldson is a tree from the USDA-ARS variety collection with more than 100 years of USDA-ARS research. 

Records show that the tree was first planted more than 30 years ago, around the time the Hamlin variety was planted. Both have similar characteristics, including that they are both early-season trees that mature from December to January. 

According to Mattia, future research should explore whether Donaldson could replace Hamlin fruit in juice by comparing fruits from trees of the same age, alluding to the variety being a great alternative.

USDA-ARS researchers also plan to work with research collaborators and industry partners to assess Donaldson’s tolerance to HLB in field trials and study the possible underlying genetic mechanisms responsible for tolerance.