Profiling volatile compounds in fresh leaves of 22 major oolong tea germplasm cultivated in Fujian of China

Tea is highly esteemed by consumers due to its distinct aroma and the abundance of nutrients that contribute to human well-being. While volatile compounds in fresh tea leaves serve as the essential foundation for tea aroma, the understanding of cultivar-specific aroma constituents and their genetic regulation remains a research gap. In this study, we extracted and profiled the volatile compounds in fresh leaves from 22 major oolong tea cultivars using gas chromatography-mass spectrometry. A total of 140 volatile compounds were identified, of which 61 were consistently found in all tea cultivars. The volatile profiles of the 22 tea cultivars exhibited considerable dissimilarity, with several distinct cultivar-specific volatiles identified. Subsequent analysis of nonadditive volatiles in tea hybrids revealed a noteworthy positive mid-parent heterosis (MPH) in 'Mingke 1' (also known as 'Jinguanyin') and 'Huangmeigui'. Comprehensive heterosis across various volatile compounds was also documented. Our study elucidated the composition of volatile compounds in the fresh leaves from the major oolong tea cultivars and provided an extensive exploration of volatile heterosis in tea plants. These cultivar-specific volatile variations will offer essential insights for enhancing the genetic aspects of tea aroma flavor and deepen our understanding of the molecular mechanisms underlying volatile compound formation in fresh tea leaves.