Advances in tea [camellia sinensis (L.) o. kuntze] breeding

Abstract

Tea is the most popular beverage, prepared with leaves of Camellia sinensis (L.) O. Kuntze, consumed by almost all communities and has economic, medicinal and cultural importance. The tea plant originated in southwestern China around 5000 years ago and is now grown in over 52 countries. Tea-breeding activities first started in ancient China and the selection of promising plants from natural variability of heterogeneous populations was practiced in the early years. This chapter highlights limitations in the traditional crop improvement programs and the necessity for adopting novel biotechnological tools to overcome them. The role of tea genetic resources in crop improvement, an overview of tea genetic resources in the world and conservation attempts made to date are discussed. Molecular markers have been used to improve the crop in tea-growing countries. The progress and significant achievements of marker-assisted selection for important traits are highlighted. A comprehensive account is given of genetic linkage maps constructed. The recent developments in functional genomic research and the progress of the omics approaches in tea are discussed. Several attempts have been made to identify functional genes associated with important traits. The progress of transgenic research in tea during the last two decades is summarized. The first genome sequence of tea was reported in 2017, which is a milestone in genome research. Mutation breeding has the potential to be used as an alternative tool to develop new cultivars in tea. The progress on controlled hybridization between selected parents, the most preferred strategy for tea crop improvement to date, is discussed. The chapter provides an overview of the current status and future prospective on the application of new technologies to combat global climate change.