Variations of main quality components of tea genetic resources [Camellia sinensis (L.) O. Kuntze] preserved in the China National Germplasm Tea Repository

Abstract

The variations of the main quality components of tea, tea polyphenols, catechins, amino acids, caffeine, and water extract of 596 accessions Chinese tea genetic resources, preserved in the China National Germplasm Tea Repository (CNGTR), were analyzed. Tea polyphenols content on a dry weight basis varied from 13.6 to 47.8%, averaging 28.4%. The tea polyphenols content increases gradually from northern and eastern provinces to southern provinces, the highest is in Yunnan tea resources. The content of catechins ranged from 81.9 g/kg to 262.7 g/kg, averaging 144.6 g/kg. The genetic resources from Hunan province had the highest catechins content, inconsistent with the tea polyphenols, which were highest in Yunnan tea resources. The amino acids content ranged from 1.1 to 6.5%, with an average of 3.3%. It was much lower in the southern provinces compared with northern and eastern provinces. The average caffeine content was 4.2%, varying from 1.2 to 5.9%. Yunnan province has plentiful high caffeine genetic resources, next is Fujian province. Caffeine content of Chinese and Japanese tea genetic resources were very similar. The average of water extract content was 44.7%, varying from 24.4 to 57.0%. The variation pattern was similar to that of tea polyphenols. Tea genetic resources of transnormal components are valuable and they could be used directly or indirectly for commercial functional components extract, breeding, and production.