Identification of QTLs controlling hydrolyzable tannin contents derived from a wild tea relative, <i>Camellia taliensis</i>

‘MK5601’ is an improved tea cultivar with genetic material from Camellia taliensis, a wild relative of the tea plant, Camellia sinensis. ‘MK5601’ differs from common tea cultivars in being rich in hydrolyzable tannins such as theogallin and G-strictinin, which have presumed health benefits. We identified two quantitative trait locus (QTL) clusters with powerful effects on hydrolyzable tannin contents in a population derived from a cross between ‘MK5601’ and an elite green tea cultivar ‘Saeakari’. The C. taliensis-type alleles at each locus in ‘MK5601’ increased the hydrolyzable tannin contents. The two QTL clusters were detected in 2 years and were confirmed in another population. These clusters have pleiotropic effects on tannin biosynthesis, as they are associated also with catechin contents. There was a strong negative correlation between the contents of hydrolyzable tannins and non-galloylated catechins. Despite the remarkable compositional changes, the two QTL clusters did not affect tea flavor. These QTLs provide important basic knowledge for developing new tea cultivars and tea products with high contents of hydrolyzable tannins and good health-promoting effects.