Assam: Cross-pollination threatens tea's originality

Guwahati: The gradual loss of original characteristics of Assam tea varieties has left the plantation industry worried after an IIT-Guwahati professor’s research has  flagged the hazards of excessive cross-pollination of tea plants.

Due to cross-pollinating, maintaining purity of a tea variety becomes challenging.

The research revealed that tea plants are cross-pollinating in nature and accept pollens from other species for fertilisation. This has gradually given birth to more than 325 sub-species or varieties of tea plants.

Assam is the single largest tea-growing region in the world. The low altitude, rich loamy soil conditions, ample rainfall and a unique climate help it produce some of the finest orthodox leaf teas.

Prof Rakhi Chaturvedi of the IIT’s department of biosciences and bioengineering, who has been doing research on this phenomenon for about a decade, has suggested that to prevent the gradual loss of the original characteristics of Assam tea, the plantation industry should undertake frequent content analyses to monitor the quality in terms of the basic qualities.

The professor said that at the local level, the growers should avoid using the seed propagation method and take recourse to cutting propagation method to avoid propagation of cross-breeds.

Tea species are identified basing the presence of major percentage of the original characteristics of a particular type. But, the fact remains that the impure varieties — the heterozygous diploid — are flourishing more in the tea plantations nowadays, she said.

Tea plants have three original parents —Camellia assamica ssp. assamica (Masters), Camellia sinensis L.O. Kuntz and Camellia assamica ssp. lasiocalyx (Planch MS). Assamica tea originated from the forests of Assam in north-east India and the sinensis tea from Sichuan province, south-western China. The third one is Cambod or Southern type. All of them are independent of one another and they are parents of tea plants available all over the world today.

The Camellia assamica (Assam type) has the largest size of the leaf and it contains the highest amount of catechins, compared to the other two, while the Chinese type has the smallest size of leaf and lower amount of catechins and the third one has intermediate size of leaf and catechins. Qualitatively or from a medicinal point of view, the first one has the highest medicinal metabolites.

Assam’s unique environmental conditions give the teas their special quality, reputation and character and help orthodox Assam Teas to qualify as a Geographical Indication (G1). Assam Orthodox teas are defined as “teas grown and manufactured out of the basic Camellia Sinenses var. Assamica and other variants in tea estates located in the Brahmaputra or Assam Valley in North East India”.

It is noteworthy that tea produced in Assam has always been improving its quality.

This was quite obvious when tea auction in the state reached a new high recently when a brew from the Manohari tea estate in Dibrugarh district fetched Rs 39,001 per kg.

It was a world record for the special boutique quality orthodox tea.