Scientific Perspectives of Tea Plant Horticulture and Productivity

By L. Manivel

Scientific Perspectives of Tea Plant Horticulture and Productivity is a complete, step-by-step guide on how to maximize tea plant growth, yield and quality. Chapters focus on the methods of cultivation, soil and water management, plant physiology, plant protection and weed control, problems from pollution and climate change, and eco-friendly remedial actions. This is an essential read for plant biologists and tea horticulturalists as the tea industry is struggling due to high production costs, changing climates and diminishing plant yields, with countries in Asia declaring the industry at ‘crisis point.’

Horticulturalists need solutions to problems with plant productivity, quality, stress management and eco-friendly cultivation practices. There have been several technological advances in the field and horticulturalists need guidance on how best to implement new technologies, hence the importance of this new resource.

• Written by a tea industry expert with almost 40 years’ of experience
• Provides a practical guide on all aspects of tea cultivation, with step-by-step protocols
• Includes plantation troubleshooting and other remedial actions

• Language: English
• Publisher: Academic Press
• Release date: Oct 31, 2021
• ISBN: 9780128236482

L. Manivel

With over 40 years’ experience, Dr L. Manivel is a renowned expert in the tea industry. Dr Manivel began his career in academia as an assistant lecturer at the Tamil Nadu Agricultural University, India, in 1967. In 1969 he began work as an assistant horticulturalist at the University of California, Davis, USA. Dr Manivel made the move to industry in 1989 by joining the Tocklaid Tea Research Association and UPASI Tea Research Institute, India, as a horticultural researcher. He served as a scientific consultant in tea, principally in India and Sri Lanka, over the last 20 years and has focused on diagnosing growth problems in the field and advising on cost-effective remedial measures. Dr Manivel published extensively in the 1990s (which is why despite his extensive academic background, he does not have a current h-index) and now has his own horticultural consultancy.

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Preface

Tea is an evolved beverage used for pleasure and health. A good cup of tea in the morning and evening cheers up and recharges. Its origin, development, and spread have been amply documented. This is one of several agri-horticultural plantation crops with advanced field and processing practices, with marketing of the produce developed and streamlined by the pioneers, which has made tea one of the premier world beverage crops.

Taxonomically, tea (Camellia sinensis, Theaceae) is a tree by habit, and it has been managed as a bush to facilitate harvesting by workers, especially women. The plant part harvested periodically is also unique—the emerged succulent flush of two leaves and the bud. It is pertinent to note that the flush harvested in the south is of the three-plus bud, which is more fibrous and less succulent instead of two-plus bud in the north. This is used for making the sought-after commercial tea.

The field packages like pruning, training the bush, architecture, moderating the ambient climate for economic growth and productivity of the bushes through judicious planting of legume trees, design of inputs, processing, marketing, and providing the infrastructure are unique, and hats off to the brave, intelligent, and hardworking pioneers!

Working with tea is a pleasure and privilege. We are working with an organized living creature, disciplined, sincere, dedicated, hardworking, toiling day and night, and compensated with rewards and incentives. Although forestland has been utilized for tea plantations, the industry is conscious of the environment protection by maintaining three-tier vegetation thoughtfully planned, designed, and executed. Despite the isolation and adversarial conditions, working in tea plantations leads to pleasure with longer life into late senescence. Considering the global change of climate and pollution due to industrialization and real estate, plantations are fairly free, despite the fact the soil and environment affected by hard chemicals imported and used indiscriminately, which ruined the soil/plant biospheres in the last two decades, needs to be rectified and restored on priority.

While I was traveling from Kolkata to Jorhat for joining Tocklai on February 01, 1976, a planter friend, Tiwari of Octavius Steel, pointed down and showed the pruned fields of tea in the plains. My eyes were opened to confirm there were tea plantations in the plains. Because I was familiar with the plantations in Travancore, Kerala, Nilgiris, Anamallais, and Tamil Nadu, which grow in rolling hills, evergreen, and with flushing throughout the year, I realized the variations of field situations include growing and flushing behavior of bushes, crop distribution, inputs, harvesting, manufacturing, and types of made tea between North India and Southern India including Sri Lanka.

Ethnically, the plantation workers in southern India, Sri Lanka, Malaysia, Mauritius, Indonesia, Parts of South Africa are Tamil, while the northern plantations possess the work force of Central and North India, Bihar, Orissa, Madhya Pradesh, and Andhra. These ethnically differing worker populations of about 25 lakhs merged and integrated with local population to an extent in five generations, speak a mixed common language, lost their roots, and have emerged as the formidable, dependable, disciplined, skilled work force awaiting the benefits of welfare measures for rehabilitation, uplift, settlement, consensus in collaboration with the concerned state governments to join the mainstream and continue to enjoy the rights of a citizen of independent India. Health and efficiency of the workforce play an important role on growth, productivity, quality, sustainability, and profit margin of the plantations. The present conditions of the tea industry and its potential, based on the unique, complex, historical background, social impacts, and so forth, deserve due consideration bearing in mind that the productivity and quality are influenced by many factors such as climate, soil terrain, cultivars, processing and manufacturing, and package of practices, in addition to the efficiency of work force. These are to be taken into account by the administration/authorities, and all the stakeholders of the industry, before implementing the ensuing package for the revival of the tea plantations of the nation.

The present condition of stagnating crop productivity with deteriorated quality, coupled with remunerative price realizations, are due to the overexploitation of bushes that impact the soil, plant biosphere, weakening the bushes predisposed to pests and diseases, and escalating the COP. Consequently the bushes are going through chronic stress due to inbuilt toxins, weakened defoliation, die back, and mortality, causing excessive vacancies of both tea bushes and shade trees. Remedial measures for restoring the health and productivity lies on the reclamation of soil–plant biospheres, withdrawing all the hard chemical uses, moderating inputs, integrating the INM and IPM, encouraging, bioproducts in an ecofriendly way, adopting natural farming, GAP optimizing the soil parameters, ensuring timely effective harvest of the crop, and processing and marketing the crop effectively. The turnaround is expected in a year, which is a win-win situation.

Another important aspect is the uprooting age for tea plantations. Because tea is a perennial crop, it has no age limit provided the optimum conditions for growth are provided. Any deficiency or sickness debilitates the bushes, and weaker bushes become sick and die. It is not natural but happens from mismanagement. The cambium tissue in the vascular bundle generates new growth every year, forming annual rings in perpetuity. The marginal surplus lands can be uprooted, reclaimed, and replaced with interplanted/consolidated with suitable horticultural, spice crops, afforestation, and so forth, with advantage. This will be an effective alternative for economical, judicious discretion for effective better utilization of surplus and marginal lands in the gardens. Forage crops with dairying can also be thought of as part of diversification and value addition.

Divine guidance and encouragement from faculty members, along with the timely help and encouragement from family, well-wishers, and close friends, have resulted in this book: a small contribution to the scientific society of the world. I thank them, and I am grateful forever.

I dedicate this book for the following faculty members at UCD who taught and trained me:

Robert J. Weaver, Mentor, Phytohormones, Grapes

Julian Crane, Graduate Adviser, Fig, Pistachio

Eric C. Conn, Plant Biochemistry

Robert W. Glocks, Vice Chancellor, Finance

Harold P. Olmo, Plant Breeder, Grapes

Albert J. Winkler, Emeritus Scientist, Viticulture

L. Manivel

Coimbatore

February 11, 2020

Chapter One: Botany origin and spread of tea cultivars

Abstract

Tea is a health beverage. The earliest tea production began in China. The Chinary cv. originated from the China mainland, while the Assam and Cambod varieties originated from Assam Brahmaputra Valley and Indochina Irrawadiensis. Tea, known as Camellia sinensis, Theaceae, is a dicot, genetically 2n=30 perennial, least evolved, highly adapted, relishing acidic soils both hills, plateaus, and valleys to various terrains, climate, soil, and rain distribution, with C3 Pn.

Keywords

Camellia; sinensis; Hybrid vigor; Liquor/aroma; Phasic growth; Photorespiration; Photosynthesis; Taproot

1.1 Characteristics of the species (a list of Assam, Cambod, and Chinary tea bushes TV3, TV 7, TV 9, AV2, and P126)

1.2 Germ plasm preservation of tea

1.3 Statistics

1.4 Excerpts of J. Thomas statistics, Kolkatta 2019 report, and UPASI Coonoor, planters Chronicle, August 2020

1.5 Impact of pandemic on Indian tea

Camellia sinensis (L) O.Kuntz is the botanical name of cultivated tea, having three recognized subspecies, such as Assam Camellia sinensis var. assamica; Camellia sinensis sub. sp., lasiocalyx, Cambod, C. Camellia sinensis var. sinensis, with origin in different places like Assam (Saikowa, Brahmaputra valley), Cambod (Iravathy River valley, Indochina) and the Yunnan valley (Yiantsikiang river valley of China), the oldest known and cultivated by China belonging to Theaceae.

Among the three cultivated species, Cambod is the most vigorous and tall growing, with high potential of yield, but it suffers in quality. Assam is the next-most vigorous, with broad succulent bulliform leaves contributing for the strong liquor and aroma sought after for blending and packaging. China cultivates the bushy type with slender stem and small, semierect orientation of leaves (often with a purple tinge and prominent serration), known for the rich flavor like Darjeeling premier tea. Tea is a C-3 plant occupying the bottom of the ladder of evolution, with a low rate of photosynthesis and higher loss of carbon due to photorespiration, compared to the C-4 plants, which are more evolved. It is a tree but trained as a bush/shrub through periodical pruning to facilitate easy harvesting of immature shoots (flush), which are used for the manufacture of the commercial tea.

The British East India Company sent explorers from Calcutta with army personnel who brought China variety seeds from China and introduced in the Botanic Garden, Howrah, Dibrugarh in Assam, Wyanad and Nilgiris in South India, and Himachal in north India, successfully establishing the China tea. The first consignment made to the UK was well received, and the East India Company with the Army helped explore it in Assam, where they picked up the broad-leafed (Betjan) Assam seed jat, by Major Robert Bruce accompanied by Assamese local planter Diwan in 1816. Their search continued, and they picked up the elite plant in 1888. After selection, propagation, and evaluation in field studies during the end of the 19th century, the elite plants of three types of tea had been procured and introduced for evaluation, comparative examination, and the later release of Tocklai vegetative cultivar (TV) clones.

Through the introduction of tea and selection activities initiated in 1911, at the Kolkata Botanic Garden, the present Tea Research Station was established in Tocklai, Jorhat, Assam in 1930 with scientist (Dr. William Wight) as botanist, initiating selection and breeding of new varieties of tea and propagating tea vegetatives. New species like Irrawadiensis and Camellia sasanqua were added to the germ plasm.

Breeding and selection of new varieties were intensified. Triploids and polyploids were produced and new clones with gene map and traits were documented through the botany Tocklai, under the leadership of the senior botanist and plant physiologist, until 1962. Proven progenies and cultivars were distributed to Sri Lanka, Kenya, South Africa, and later to other countries like Japan, Russia, Australia, Argentina, and Turkey through this Institute. (For more details on the distribution and spread of tea, please refer to Percival Griffiths, 1951; Barua, 1989, Baruah, 2006, 2019a,b; Carr, 2018).

The areas where tea was cultivated steadily expanded; consequently, demand increased for planting materials and new improved varieties of tea. Breeding, pure-line selection, and establishment of seed orchards for biclonal stocks were intensified, contributing new elite cultivars in the 1980s and meeting the expansion programs of the industry. TV1 was the first elite clone picked up and released from Tocklai in 1954. A good number of TV clones, biclonal stocks, and pure-line selections were released and added to the germ plasm. Quite a few garden clones were also released by pure-line selection and introduced for regional acceptancy, productivity, as well as quality (a few are listed here: S3A1, S3A3, T3E3 Jorhat, Assam type, P126, NH 431, R92, AV2 Chinatype, TeenAli17, TRI, 2024, 2025, and 2043 Cambod type). Thus, these decades (1970s and 1980s) were the most productive period for Pioneer, Tocklai Experimental Station, Jorhat, and Assam, supporting the tea industry and boosting the area, productivity, quality, and value realization (Tocklai Conf. Proceedings, 1981; Barua, 1989; Baruah, 2019a,b). Though many clones were released later for different aspects/purposes, the first clone, TV1, is still considered number one for productivity, quality, stress tolerance, and for being a good blending clone despite its few setbacks such as brown, fibrous-made tea, and susceptibility to red spider mite. It is a potent mother-bearer cultivar, evolving biclonal stocks, as well as a mother plant for future breeding