Accelerating Implementation of Huanglongbing-tolerant Hybrids As New Commercial Cultivars for Freshand Processed Citrus

Abstract

Citrus greening or huanglongbing (HLB) has reduced citrus and especially orange yields, resulting in closure of packing houses and processing plants in Florida. To maintain the remaining packing and processing infrastructure, a National Institute of Food and Agriculture (NIFA), Citrus Disease Research and Extension (CDRE) grant was obtained to identify hybrids in breeding programs with HLB tolerance and commercial quality for either the fresh fruit or processed juice industry. The proposed research would also determine HLB resistance or tolerance DNA markers for marker assisted breeding or use in transgenic programs. This paper will discuss the first season performance of some of these hybrids for their intrinsic flavor quality and similarity to either orange or mandarin, since both orange and mandarin are present in the hybrids’ genetic backgrounds. Both sensory and chemical evaluations for flavor were conducted. Several commercial cultivars were also harvested and evaluated for comparison. These hybrids were harvested once or multiple times over the season. Out of the 20 hybrids evaluated, 7 exhibited orange similarity, and most scored relatively high for orange flavor in at least one harvest. One of these hybrids has since been released as ‘U.S. SunDragon’. Seven hybrids exhibited similarity to mandarin and/or mandarin flavor, with three that also had similarity to orange. Overall, the trial showed that there is much diversity in the breeding programs for flavor, sugars, acids, and bitter limonoids. There is also potential for both HLB tolerance and commercial quality. Hybrids with HLB tolerance and good flavor would be candidates for citrus juice blends.