1. Presentation on,
“TEA IMPROVEMENT”
By,
Shivanand M R
Jr. MSc.

2. Introduction
 Tea is the most favorite beverage of the people world over.
 The history of tea dates back to 2737 BC.
 It is believed that the tea originated in China.
 According to a Chinese legend, Shen Nung, the second
emperor of China, who is considered as the father of
agriculture and the inventor of Chinese herbal
medicine, invented tea accidentally.
 The story goes like this. One day while he was sitting in
the garden some leaves fell in to his cup of water, the
emperor happened to taste that water which had a nice
aroma and flavor, thus the tea leaves was discovered.

3.  Tea is an important plantation crop and native of South
East Asia.
 India is the largest producer, consumer and exporter in
Tea industry, India has 4,36,057 ha area under tea, of
which 87,993 ha is in the south.
 As on today, 38 countries grow Tea and among which
India, China, Sri Lanka and Indonesia have major share in
area and production.
 Major states producing Tea in India
are, Assam(53%), West Bengal(24%), Tamil
Nadu(13%),Kerala(8%),Karnataka(0.7).
 Tea was first planted on a large scale in North India in
1834, while in South India commercial tea planting was
started at various tea growing regions like Nilgiris
(1859), Central Travancore (1875), Kannan Devan Hills
(1878), Wynad (1859) and Anamalais (1897).

4.  Tea research was started in North India during 1960 and 'in
South India during 1926.
 "Tea" refers to the aromatic beverage prepared from the
cured leaves by combination with hot or boiling water, and
is the common name for the Camellia sinensis plant itself.
After water, tea is the most widely consumed beverage in
the world.
 It has a cooling, slightly bitter, astringent flavour which
many enjoy.

5. Botany
 Tea belongs to the genus Camellia and family
Camelliaceae or Theaceae, Tea is a diploid i.e (2n=30).
 This genus accommodates as many as 82 species
(Sealy, 1958) and over 200 species (Zhijian et a l., 1988).
But only two species viz., C. assamica (Assam jats) and C.
sinensis (China jats) are the original species for tea. As
they were highly crossable with each other, the present day
tea seedlings are hybrids of these two species and are often
referred as C. assamica sub sp. Lasiocalyx (Indo-China or
Cambod type)
 The commercially cultivated tea consists natural hybrids of
all these three types and there is reason to believe that
complex hybrids of these three types of tea and one or
more of the wild species of Camellia occur in the
cultivated populations.

6.  Tea is essentially an out breeding crop and its races are
highly infertile. As a -result of enormous natural
hybridization not only between the tea species but also
with Camellias and large,-scale dispersal of tea seeds in
south-east Asia over the centuries, resulted in extreme
heterogeneity in the existing seedling population.
 Tea taxonomy is very complicated, and hybridization early
in its commercial history has left an almost total absence
of pure plants (Willson, 1999).

7. Botanical Composition of Jats
 The term 'jat' in tea nomenclature is considered close to
'variety'.
 The multi-stemmed China type has two jats - 'Low-jat' and
'High jat'.
 The former 'jat' has narrow leaves, profusely indented
margin and flat, rather dull-coloured laminae, whereas
later has comparatively larger leaves, wider in proportion
with blunter tips, fewer serrations and a crinkled surface
(Subramanium, 1995).
 The single-stemmed Assam type has
Burma, Lushai, Manipuri, light-leaved Assam and the
dark-leaved Assam jats.
 Burma jat comes from Myanmar hills and has
spiny, crinkled and slightly erect leaves ,and has dark-
green, older leaves having a bluish tinge.

8.  Lushai is form of Lushai hills and has pendent flabby
leaves.
 Manipuri is a hardy, and high yielder of quality tea.
The leaves are dark-green, shiny, rather narrow and
have a semi-upright leaf pose. It is softer than Burma
jat.
 The light-leaved Assam is found in the Naga hills and
has a semi-upright, glossy, crinkled, light green
leaves.
 The Lushai and the light-leaved Assam are generally
not planted in Assam because the former is very
delicate and the later is poor yielder and has a
balsam-like odour.
 Dark-leaved Assam has soft, glossy, crinkled and
slightly pendent leaves (Subramanium, 1995).

11. Biology of the Plant
 Vegetative Structure
 Under natural conditions, the tea plant is an evergreen tree
and wildly grows into a medium size tree.
 Under cultivation it is pruned down and trained as low
spreading bush to ensure that a maximum crop of young
shoots can be obtained and maintained.
 Leaves are simple, alternate and serrated.
 The root system of a tea bush can be divided into main
roots, subsidiary roots and feeder roots. The lateral roots
give rise to a surface mat of feeding roots which lack root
hairs when mature.
 Root system varies in tea bushes depending on genetic
makeup and soil environment. Starch is stored in roots.

13. Reproductive Structure
 Tea flowers appear in the axils of scale leaves, either
solitary or in clusters, with short pedicels, fragrant; calyx
persistent with 5-7 sepals; petals 5-
7, white, waxy, obovate, concave; stamens numerous with
2-celled yellow anthers; petal and outer stamens united for
a short distance at base ovary superior, hairy, with 4-6
ovules per carpel; styles short, free to almost completely
fused, stigmatic lobs 3-5.
 Fruits are capsule thick walled, brownish green, 3-lobed
and usually 3-celled, becoming slightly rough at
maturity, dehiscing during the dry period by splitting from
apex into 3 valves.

19. Plant Improvement
 Introduction
 The tea plant is predominantly cross pollinator and highly
heterogenous.
 It was observed that tea sets better with pollen from another
bush, the average set of the plant with its own pollen being
about one quarter of that obtained by cross pollination (Wight
and Barua, 1939).
 Further, selfing results in smaller seeds with reduced
germinability or no seeds at all (Mamedov, 1961;
Sebastiampillai, 1963).
 Breeding in the strict sense and evolution of pure line races in
the polymorphic species Camellia sinensis are time consuming
and be set with practical difficulties. Fortunately, a large
variation in several important and desirable characters occurs
from bush to bush in the existing tea populations.

20.  Exploitation of such plant variability by careful selection
for high yield, excellence of cup characters of made
tea, fair resistance to drought and some important pests
and diseases and adaptations for different environment
appear to offer a ready means of developing improved
planting material in this perennial crop.
 Other objectives of breeding vary according to the
requirements of different regions. The achievements of all
desirable objectives simultaneously will not be practicable
but some of these can be realized at a time through the
selection of novel plants and their multiplication as
vegetative clones or by breeding improved strains of
seeds.

21. Selection Procedure
 Selection of mother bush from the existing population is
most important for production of improved seed and clonal
varieties or hybrids. The fact that a tea bush in a field
appears vigorous and apparently healthy does not mean
much because it may produce huge crop of inferior tea, or
a less amount of crop of superior tea. The bush population
even in a small field of tea shows great variation in regard
to growth habit, inherent quality and yield.
 Wight (1939) observed that about 10 percent of the bushes
in a commercial plantation in north eastern region produce
only 2 percent of the total crop and about 0.5 percent
bushes produce as much as or more than 300 percent of
the yield of an average bush.

22. Development of Clonal Varieties
 In seed-grown tea, existence of wide variation are well known
to the tea breeders and this probably made them aware of the
advantages of clonal propagation for establishing large and
uniform population.
 Clones are plants genetically identical to the parent originating
by vegetative propagation such as by leaf cuttings or grafts
taken from tea bush.
 Possibilities of propagation by single leaf and internode
cuttings was explored in India (Tunstall, 1931), Sri Lanka
(Tubbs, 1932) and Indonesia (Wellensick, 1938a, 1938b). The
technique streamlined subsequently, assisted in the rapid
multiplication of selected mother bushes leading to the
development of clones (Kehl, 1963; Venkataramani, 1970;
Wight, 1960).
 This encouraged tea breeders to develop clonal varieties.
Clonal selection also involves considerable time and is a
laborious process but widely adopted method of plant
improvement in tea.

23.  It usually takes 7-10 years before a clone could be released
for commercial planting (Barua, 1963b; Bezbaruah, 1968).
The initial selections were done on the basis of colour and
size of shoot, pubescence, branching habit, bush
area, recovery rate following pruning etc.
 In clones, rooting character to a great extent is inherent
and three types of root systems viz. shallow or
horizontal, vertical and intermediate are commonly
known. In the shallow and horizontal root system, all roots
develop at the surface and run almost parallel to the
ground which is obviously undesirable in a perennial rain-
fed crop like tea. In the vertical system, one of the roots
tend to go down almost vertically, gradually thickening
and functioning as tap root.

24.  This type is rarely found. The intermediate root system is
most commonly come across and in this type at least one
of the root grows at an angle of 30 to 45 from the
horizontal and penetrates deep into the soil
(Venkataramani, 1970).
 The development of superior clones with high yield and
better quality has been one of the major achievements of
the Tocklai breeding programme. UPASI Tea Scientific
Department and R & D Department, Tata Tea Ltd as
recombinant genetic variability has been fixed.

25.  UPASI scientific Department stated that the initial clonal
selection may be eye judgment by examining the bushes
for such features as recovery from pruning, wood
formation, branching habit, flushing behaviours, colour
and size of leaves. In brief, the eye judgment could be
based on the following features.
1) The number of stems per unit area of the bush should be
high and their distribution should be uniform over the
entire area of the bush.
2) The individual stem should not be thin and whippy and it
is also important that variation in thickness of the stems
should not be high.

26. 3) The size of the bush need not necessarily be large but
consistent with factors detailed above: a bush, showing a
tendency to fill in quick with an early lateral spreading
habit is desirable. These characters can be determined just
before or at the time of pruning or in the first year from
pruned.
4) The density of plucking points per unit area should be
high.
5) Uneven growth of the shoots is not desirable and it is
therefore necessary to select for evenness of bud break and
growth of shoots.
6) The main branch and the primaries developing from them
after pruning should have straight or erect growth and not
oblique or horizontally spreading habit.
7) The bigger the leaf, the larger the weight of the shoot and
hence greater the yield.

27. 8) There seems to be a relationship between the colour of the
leaf and cup quality, light coloured leaves generally
produce better tea than dark coloured ones.
9) Selection may also be made for pubescence of buds and
leaves, a selection with pubescence flush generally
produces tea with better quality than with glabrous flush.
10) Resistance to blister and other diseases and pests and
drought are some of the factors to be considered in
selection for yield, it would be useful to compare the yield
per unit area of plucking surface of the selection bush with
the yield per unit area of the field during the period of
experimentation (at least three continuous months). The
ratio is termed yield potential. The greater the ratio the
greater is the potentiality for yield.
 Yield potential= Bush yield per unit area
Field yield per unit area

38.  Among these, clones such as UPASI-3, UPASI-8, UPASI-
17, UPASI-25, UPASI-27, UPASI-28 and TRF-1 are high
yielders.
 Clones such as UPASI-2, UPASI-6, UPASI-9, UPASI-20
and UPASI-26 and the TRF 3 are moderate yielders but are
tolerant to drought.
 Certain Sri Lankan clones such as TRI-2024, TRI-2025
and TRI 2026 and a few estate clones such as CR-
6017, C-1, ATK-1 and SA-6 are also widely used for
planting in southern India.
 Certain clones such as CR 6017, UPASI 3, TRF 2, are
known for their quality.
 Current clonal selection work in the
Anamallais, Nelliampathy and Nilgiris resulted in the
selection of 140 bushes based on visual examination.
Studies are in progress to monitor their nursery and field
performance .

39. BICLONAL SEED STOCKS
 Besides the clones, five biclonal seed stocks have also
been released for commercial planting.
 The biclonal seed stocks are UPASI: BSS-1 to BSS-5.
 These seed stocks germinate early in the nursery and
establish well in the field. They are good for
infilling, replanting and extension planting. The stocks are
moderate yielders but are tolerant to drought.
 Seed bari blocks for all the five seed stocks have been
established in the Research Institute and in other planting
districts for supplying seeds to the tea growers.
 In the current hybridization programme crosses were made
between UPASI -9 and the drought tolerant clone C-
1, blister resistant clone SMP-1 and the quality clone CR-
6017. Progenies derived out of all these crosses were
planted in the field for studying their field performance.

40. Hybridization
 In tea, due to self-sterility, pure lines breeding by
conventional techniques is not possible . Tea can be
genetically upgraded through hybridization.
 This can be done by transferring desirable characters from
the parents by hybridizing them to develop seed cultivars.
The seed obtained from crosses between two clones is
known as biclonal seed which show considerable variation
in genotypic characters while retaining a certain amount of
phenotypic uniformity.
 Such inherent variation is important for the development
of clones, which in turn could be used in evolving seed
stocks.

41.  After evaluation of germinability and growth performance
of biclonal progenies in the nursery on the basis of
height, stem diameter, root and shoot ratio; the field
performance of the' progenies are evaluated in the same
manner as that described under clonal selection.
 Hybridization between genetically diverse parents
introduces improved hybrid vigour which often reflected
higher yield in the progenies.
 Therefore, a clone-seed cycle is important for continued
plant improvement and its appropriate commercial
exploitation (Banerjee, 1992; Satyanarayana and
Sharma, 1993).

42.  Hybridization also helps in broadening the genetic base as
genes from plants with different genetic linkages could be
brought together. However, only a limited success has
been achieved in developing cultivars through sexual gene
transfer because of certain limitations such as large size of
the plant and long-duration, generative cycles ranging
from 5 to 10 years (Subramaniam, 1995).
 Production of synthetic seed varieties was one of the early
breeding efforts at Tocklai, Assam. A group of selected
clones were planted in isolated seed orchards to produce
the seed under natural conditions. Such seed are
commonly known as polyclonal seed. These seeds were
found to be of unpredictable performance and more
unstable than biclonal seeds (Singh, 1982).

43. Interspecific Hybridization
 In tea natural interspecific hybridization between different
Camellia species are not common and limited attempts
have been made for artificial induction of interspecific
hybrids.
 Wight and Barua (1957) attempted interspecific
hybridization between Wilson's Camellia (c.
irrawadiensis) and C. sinensis var. assamica.
 Experimental F1 hybrids resembled the later in many
morphological characters but were inferior in quality
which was not accepted commercially.

44.  A successful hybridization between C. sinensis and C.
japonica has been reported by Bezbaruah and Gogoi
(1972).
 F1 hybrids showed close morphological similarity with
parents but yield and quality were low.
 Generally, hybridization with species of Camellia from
which acceptable quality of tea can be manufactured have
been encouraging. But there are exceptions. For
example, a high yielding clone TV 24 in Assam produced
from the crossing between F1 hybrids from C.
irrawadiensis x C. assamica Shen and TV 2, an Assam-
China hybrid (Bezbaruah, 1987).

45.  There may be scope for introducing non-conventional
approaches to tea improvement. But the potential of non-
conventional methods is limited by lack of knowledge of
some aspects of tea genetics.
Mutation
 Attempts at inducing mutation in tea
seeds, cuttings, pollen grains with physical (X-rays and G-
rays) and chemical mutagens (Ethyl Methane Sulphonate)
have not yielded desired success to produce superior
mutants. Mutants produced by these treatments have
stunted growth, reduced vigour, and a lesser number of
foliage and branches (Singh, 1982).

46.  The use of irradiated pollen also caused fruit drop
(Satyanarayana and Sharma, 1993).
 The difference of responses to G-rays was also observed in
tea clones.
 Cambod origin are comparatively less tolerant to G-rays
than China and Assam origin (Singh, 1980).
 The apparent genetic variation in the response of mutagens
suggests that the technique has potentiality in tea breeding.

47.  Most of the cultivated tea all over the world is diploid (2n =
30). Natural triploids (2n = 45) resulting from open pollination
are reported from Japan (Simura and Inabe, 1953), north-east
India (Anonymous, 1970), south India (Venkataramani and
Sharma, 1975), Georgia (Kapanadze and Eliseev, 1975); and
tetraploids (2n = 60), pentaploids (2n = 75), Aneuploids (2n +-
1 to 29) from north-east India (Bezbaruah, 1968).
 These are commonly found in tea populations but in low
frequency (Singh, 1982). Triploids and tetraploids had bigger
leaf and havier shoots but poor in cup quality than diploids
(Sarmah ahd Bezbaruah, 1984), and pentaploids and
aneuploids were week bushes and poor rooters
(Bezbaruah, 1968).

48.  Density and morphology of sclereids and stomata proved
to be useful indices in determining ploidy level, tetraploids
shows highest density and size of sclereids and having the
largest stomata.
 In south India, a natural triploid (clone UPASI- 3) is found
to be vigorous, high yielder with overall quality and the
clone UPASI- 20 which is another triploid reported to be
moderate yielder having drought tolerant capacity
(Satyanarayana and Sharma, 1993).
 Polyploid plants (16 triploids and 2 tetraploids) have also
been identified among the east African tea clones
(Wachira, 1994).

49.  However, polyploids are in general vigorous and hardier
than diploids but they do not always contribute high yield
(Banerjee, 1992).
 Polyploids can be produced by treating with colchicine
(Visser, 1969) and crosses between triploid and diploid
clones.
 Polyploids with favourable characters could be cloned and
used in the improvement of the genetic stock.
 In Sri Lanka, triploid clone HS-10A did well in very high
altitudes compared to the diploid clones.
 Sundaram and TV-29 are triploid clones gaining popularity
in India, Sri Lanka and Kenya.

50.  The potential of tissue culture in various aspects of plant
improvement have already been recognised and attracted
the attention of scientists.
 Rapid multiplication of propagation materials through
tissue culture, particularly in the initial selection, assumes
importance in plant improvement programmes.
 Tissue culture offer opportunity to utilize
genetic, physiological and biochemical procedures in
developing ideotypes (Banerjee, 1986).
 It also holds promise in the development of pure lines
through haploid technology, production of triploids
through endosperm culture, culture of embryos of
incompatible crosses and isolation of somaclonal variants
(Singh, 1978).

51.  Banerjee (1992) suggested further possibilities of genetic
manipulation for production of pure line of tea for
inbreeding, breeding and propagation of interspecific
hybrids derived from the various combination of crosses
by cotyledon and embryo culture, fusion of protoplast
from different species to produce hybrid synkaryons which
then could be regenerated into organised plants by using
techniques of cell and tissue culture.
 Once the plants are regenerated through in vitro
techniques, it is necessary to establish the genetic
variability using Random Amplified Polymorphic DNAs
in somaclonal plants. Since they are directly linked with
DNA, these markers are more stable and are not
influenced by the environmental conditions. (RajKumar et
al., 1997).

52.  Possibility of transferring low caffeine genes from other
camellia sp. should be explored both through conventional
hybridization and transgenic approaches to the
modification of the biosynthetic pathway for caffeine
synthesis, using antisense RNA technology to selectively
switch off individual genes and block biochemical
pathways.
 The other approach is through accelerated particle gene
delivery (using 'gene gun') which has brought many
recalcitrant crops within range for genetic manipulation
(Lyer, 1995).
 Somatic cell hybridization using protoplast fusion has
been tried to transfer the Darjeeling tea flavour of 'China'
clones to the Assam cultivars possessing strong and brisk
liquors (Banerjee, 1986).

53.  For early identification of blister bight resistance or
susceptibility, SCAR (Sequence Characterized
Amplified Regions) marker has been developed.
 This DNA marker will enable us in selecting
blister blight resistant/ susceptible plants.
 Development of drought specific microsatellite
markers (SSR) are in progress.

54.  The collection of tea germplasm in India in fact began with the
discovery of Assam tea in 1823. The collections were also made
from Burma, Cambodia, China, Japan and Vietnam.
 At present over 1200 genetic stocks of tea including its wild species
and weedy relatives are maintained at Tocklai Experimental Station
(Bezbaruah and Dutta, 1977). This collection has undoubtedly
helped India as well as other tea growing countries in evolving
superior plant materials (Singh, 1979).
 The same have also been extensively used in hybridization
(crossing) programmes for the development of clonal varieties
(Bezbaruah, 1974) and its exploitation thus helped in broadening the
genetic base of certain clones.

55.  In south India, a majority of the selections available in the
germplasm at present have been selected from some of the
commercial tea estates of that region (Satyanallayana and
Sharma, 1986).
 The preservation of tea germplasm has great importance
primarily because of the seed-grown sections of tea are
being massively uprooted and the seed sources of which
no longer exist and lost forever.
 There is a vast genetic variability of plantations of
Darjeeling hills as still over 95% of the tea area is seed'
originated and old.

56.  The wide variability in the commercial tea populations
offers scope for the selection of elite mother bushes with
desirable attributes in practical plant improvement
programme (Richards, 1966; Bezbaruah, 1975).
 Therefore, it needs to be preserved and utilized
judiciously.
 Tea areas although at a slow rate are replanted with limited
vegetative clones and jungles are also being cleared for
extension of agricultural activities resulted narrowing the
genetic base of Indian tea.
 Conservation of tea germplasm is done mainly
by, establishing field gene banks comprising a wide array
of indigenous and exotic cultivars will offer the necessary
genetic diversity for the improvement of tea plant at a
future date.

57.  Ghosha Hajra, N., (2001). Tea Cultivation:
Comprehensive Treatise: 43-81.
 Kumar, N., Abdul Khader & Rangaswami, P., (2006).
Introduction to Spices, Plantation crops, Medicinal &
Aromatic Plants.
 www.upasi.org/
 www.tocklai.net/
 www.teaboard.gov.in/