GUWAHATI, July 17 - Tea plants grown world over in plantations are no longer of the pure types they used to be. They are all gradually losing their original characteristics. As tea plants are strictly cross-pollinating in nature and accept pollens from other species for fertilisation, there exists more than 325 subspecies or varieties of tea plants now.
This was the observation of Prof Rakhi Chaturvedi of the Department of Biosciences and Bioengineering, IIT Guwahati. The IIT professor, who is doing research on this phenomenon for the past about a decade, was talking to this correspondent.
Tea plants have three original parents � Camellia assamica ssp. assamica (Masters), Camellia sinensis L.O. Kuntz and Camellia assamica ssp. lasiocalyx (Planch MS). The first one is called Assam type, while the second one is called China type and the third one is Cambod or Southern type. All of them are independent from one another and they are parents of tea plants available world over today, said Prof Chaturvedi.
At present, the tea species are identified basing on the presence of major percentage of the original characteristics of a particular type. In this respect, the benchmark is the presence of the original characteristics between 60 per cent and 70 per cent of the total percentage to classify a particular type. But, the fact remains that the impure varieties � the heterozygous diploid � are flourishing more in the tea plantations nowadays, she said.
The Camellia assamica (Assam type) has the largest size of the leaf and it contains highest amount of catechins, compared to the other two, while the China 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 medicinal point of view, the first one has the highest medicinal metabolites.
It is a fact that trees have a corresponding nature and they are mostly cross pollinating. Under such a situation, maintaining purity of a variety is a tough job.
However, to prevent the gradual loss of the original characteristics of Assam tea, that is the tea grown in Assam, the tea industry of the State should undertake frequent content analyses to monitor the quality in terms of the basic qualities. At the local level, the tea growers should avoid using the seed propagation method; rather they should take recourse to cutting propagation method to avoid propagation of cross breeds in which the quality of the pollens decide the quality of the seeds and each seed is an variant of the other.
