Title: Volatile profile comparison of USDA sweet-orange-like hybrids vs ‘Hamlin’ and ‘Ambersweet’ Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 27, 2013
Publication Date: May 25, 2013
Citation: Bai, J., Baldwin, E.A., Driggers, R.E., Hearn, J., Stover, E.W. 2013. Volatile profile comparison of USDA sweet-orange-like hybrids vs ‘Hamlin’ and ‘Ambersweet’[abstract]. The Florida State Horticultural Society Annual Meeting, June 2-4, 2013, Sarasota, Florida. Technical Abstract: Volatiles of six hybrids (‘Ambersweet’ orange crossed with one of three different orange hybrids) were analyzed using a gas chromatography – mass spectrometry (GC-MS) to compare the volatile profiles with ‘Ambersweet’ and ‘Hamlin’, the most widely grown early sweet orange in Florida. All hybrids are ½ sweet orange and varying amounts of tangerine, grapefruit, Poncirus trifoliata and one putatively includes sour orange in its pedigree. In total, 136 volatiles were detected from the 8 hybrid lines/commercial cultivars over two harvests, and 20 components were detected in all samples, including monoterpenes (limonene, ß-myrcene, a-pinene, a-terpinene, terpinen-4-ol and linalool), esters (ethyl butanote, ethyl pentanoate and ethyl acetate), aldehydes (acetaldehyde, hexanal, and nonanal) and alcohols (ethanol and hexanol). Total abundance of volatiles in January-harvested fruits was 30% higher than the same fruits harvested in November. ‘Ambersweet’ contained highest amount of volatiles, and of them, nootkatone, intermedeol, and 5 other compounds were not detected in any of the hybrids, and some of them even not in ‘Hamlin’. On the other hand, 12 compounds, including pentanal, ethyl 2-butenoate, ethyl nonanoate, neral and geranial were not detected in ‘Ambersweet’, but were found in ‘Hamlin’ and some of the hybrids. Stepwise discriminant analysis selected 35 components from 136 volatiles identified, which were used to apply cluster analysis. The results show that FF-1-75-55, FF-1-76-50 and FF-1-76-52, all with the same parents (‘Ambersweet’ x ‘FF-1-30-52 [1/2 sweet orange and 1/2 tangerine]’), are close to FF-1-64-97 and FF-1-65-55, which also had the same parents (‘Ambersweet’ x ‘7-5-5 [sweet orange x unknown]’), and they are all similar to November-harvested ‘Hamlin’. They are discriminated from November ‘Ambersweet’ and further discriminated from FF-1-74-14, a hybrid with 1/8 P. trifoliata, which includes slight off-flavor frequently found in Poncirus hybrids. All those are discriminated from January-harvested ‘Hamlin’ and ‘Ambersweet’ fruit. A principle component analysis (PCA) separated ‘Ambersweet’ from all hybrids and ‘Hamlin’ along the PC 1 axis and separated November harvests from January harvests along PC 2. All the new lines are sweet-orange-like, early season hybrids in fruit size, color, and informal sensory panel flavor analysis. This volatile analysis supports the classification of the hybrids as sweet orange.