Tea: A worthwhile, popular beverage crop since time immemorial

Abstract

Not only for the age-old customs but also the recent advancement in researches has pointed towards the fact that the several beneficial components present in tea help to achieve its popularity as a second best drink after water across the world. According to World Tea News, in 2015-2016, the total world tea production reached up to 4,481,860 tonnes, in which Indian share was 28.8% (1,29,190 tonnes) and this is almost twice the amount to that of 10 years back. Similarly, world tea economy has also appeared to its healthy business figure since the last decades (28.2 billion USS in 2016). The global market is broadly controlled by black and green teas, although there are more types of teas that are being consumed according to local consumer’s perception (oolong, white, yellow, and pu-erh). Commercially, tea leaves are harvested at different stages of growth and undergo a series of processing techniques (withering, disrupting, oxidising, fixing, sweltering, rolling, and drying) before being packaged and marketed. Subject to the implementation of the all steps of processing or omitting some steps and duration, different types of teas are prepared. During processing, the phytochemicals present in green tea leaves are being greatly modified, and each variety of tea appears with specific colour, aroma, taste, and briskness after infusion. A typical agroclimatic condition is required for quality production of tea. Acidic soil, 5-10° of slopes, temperature ranging from 10 to 30 °C, minimum average rainfall 100-120 cm/year, more than 2000 mt. above sea level of eleva tion, and well drainage system are the ideal agroclimatic situation for tea cultivation. Different polyphenols and their derivative (catechin, epicatechin, epigallocatechin gallate, epigallocatechin, theaflavins, thearubigins, etc.) and several free radical scavenging elements in infused tea have proven their health assistance feature in recent researches. Conventional breeding technique is not competently applicable for this utility crop because of their self-incompatibility. Hence, several techniques of molecular breeding occupy the frontline research on tea. In this regard, molecular marker-assisted research for better facility to locate the essential gene location in whole genome sequence for the desirable agronomic traits is in lime light.