Hybrids of Poncirus trifoliata L. Raf. with Citrus have shown degrees of tolerance to the deadly citrus greening disease, hence prompting interest as potential commercial varieties. Although P. trifoliata is known to produce fruit that is inedible, fruit from many advanced hybrid trees have not been evaluated for their quality potential. The sensory quality of selected Citrus hybrids with varying degrees of P. trifoliata in their pedigrees is reported herein. Four Citrus × P. trifoliata hybrids developed through the USDA Citrus scion breeding program—1‐76‐100, 1‐77‐105, 5‐18‐24, and 5‐18‐31—had acceptable eating quality and sweet and sour taste, with mandarin, orange, fruity–noncitrus, and floral flavors. On the other hand, hybrids with higher proportion of P. trifoliata in their pedigrees, US 119 and 6‐23‐20, produced a juice characterized by green, cooked, bitter, and Poncirus‐like flavor and aftertaste. Partial least square regressions revealed that the Poncirus‐like off‐flavor is likely due to a combination of higher than typical amounts of sesquiterpene hydrocarbons (woody/green odor), monoterpenes (citrus/pine), and terpene esters (floral) and a lack of aldehydes with typical citrus odor (octanal, nonanal, and decanal). Sweetness and sourness were mostly explained by high sugars and acids, respectively. Further, carvones and linalool contributed to sweetness in the samples from early and late seasons, respectively. In addition to highlighting chemical contributors to sensory descriptors in Citrus × P. trifoliata hybrids, this study provides useful information on sensory quality for future citrus breeding efforts. Practical Application The relationships between the sensory quality and secondary metabolites of Citrus × P. trifoliata hybrids described in this study help identify disease‐resistant Citrus scion hybrids with acceptable flavor and help mobilize this resistance in future breeding efforts. It also shows potential of such hybrids to be commercialized.

Winter melon fruits were grown in the field using anaerobic soil disinfestation (ASD) and conventional fertilizer alone as the control treatment. Fruits were harvested and stored at 20 °C for 120 d, the juice was processed on day one and day 120, and the effects of soil amendment and 120 d storage on the juice’s physical and chemical (sugars, acids, volatile and nutritional compounds) properties were evaluated. Fruit juice extracted from ASD-grown fruit had greater magnitude of zeta potential than the control juice, indicating it was physically more stable than the juice obtained from the control conditions. ASD fruit juice had lower soluble solids content (SSC), and lower volatile compounds that contribute green, grass, and sulfur notes, and negatively influence flavor quality. ASD fruit juice had higher vitamin B5 and cytidine. Juice processed from 120 d stored fruit had less yield due to 12.4–15.6% weight loss. The non-soluble solids content was higher and particle size was larger, and the SSC and individual sugars decreased. However, titratable acidity (TA) increased primarily due to increased citric acid. Out of 16 free amino acids, 6 increased and only 1 decreased. However, three out of five nucleosides decreased; vitamins B1 and B6 increased; vitamins B2, B3 and C decreased. Overall, juice derived from fruit produced using ASD was physically more stable and had less SSC and off-odor volatiles than the control, while the fruit juice of those stored for 120 d had lower SSC and higher TA and nutritional profiles, comparable to freshly harvested fruit.

Sweet orange (Citrus sinensis) exhibits limited genetic diversity and high susceptibility to Huanglongbing (HLB). New HLB tolerant orange like hybrids are promising alternatives. However, the genetic control of key flavor compounds in oranges remains unknown. Evaluating 179 juice samples, including oranges, mandarins, Poncirus trifoliata and hybrids, distinct volatile compositions were found. A random forest model predicted untrained samples with 78% accuracy and identified 26 compounds crucial for orange flavor. Notably, seven esters, methyl hexanoate, ethyl hexanoate, ethyl 3 hydroxyhexanoate, ethyl octanoate, methyl butanoate, ethyl butanoate, and ethyl 2 methylbutanoate differentiated orange from mandarin. Cluster analysis showed six esters with shared genetic control. Differential gene expression analysis identified CsAAT1, an alcohol acyltransferase responsible for ester production in orange. Its activity was validated through overexpression assays. A SNP based DNA marker in the CDS region accurately predicted phenotypes. This study enhances our understanding of orange flavor compounds, their biosynthetic pathways, and expands breeding options for orange like cultivars.