UNDA MEMORIAL NATIONAL AGRICULTURAL SCHOOL

PLANT GENETIC RESOURCES AND GERMPLASM CONSERVATION

The primary justification for the conservation of plant genetic resources is given as
their importance for breeding improved varieties of crops for food, fuels and medicines.
This book is restricted to major food crops, forest trees and industrial and medicinal plants.
This chapters cover the need for, and the history of, conservation; crop evolution and
diversity; plant collection and exploration; methods of conservation; management of data
on genetic resources; using genetic resources for examples vegetables, industrial and
medicinal plants and forage grasses; forest genetic resources; and prospects for plant
genetic resources. A useful appendix lists important germplasm collections throughout the
world. The information is clearly presented and is a good introduction to the subject.

INTRODUCTION
Plant genetic resources (PGRs) are the totality of all allelic sources that affect a crop’s
spectrum of attributes, while germplasm is the genetic material passed down from one
generation to the next. This genetic diversity may have been derived from closely related
wild plant species, which are the immediate or indirect ancestors of cultivated species,
currently domesticated or semidomesticated cultivars, as well as their component cultivars,
which are either still in use or have been rendered obsolete, or landraces or historic
varieties.
Despite their availability, there are major obstacles to use these allelic resources in a
sustained and effective manner. Despite the fact that there are numerous gene banks in
existence today, only roughly 30 nations have chosen to store their germplasm there for
secure long-term storage due to a lack of long-term maintenance facilities for such gene
banks.
Additionally, the 7.5 million accessions in these gene banks include predominantly
landraces and diverse wild relatives of crops that are important for human and animal
nutrition. However, there are underutilized species and locally significant crops that require
protection.
The sum total of hereditary material i.e. all the alleles of various genes, present in a
crop species and its wild relatives is referred to as germplasm. This is also known as
genetic resources or gene pool or genetic stock. Important features of plant genetic
resources are given below:

Figure 1: Seed and Plant Genetic Resources.

 Genetic pool represents the entire genetic variability or diversity available in a

crop species.

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2 | Conservation Agriculture: Prospects and Challenges
 Germplasm consists of land races, modern cultivars, obsolete cultivars,
breeding stocks, wild forms and wild species of cultivated crops.
 Germplasm includes both cultivated and wild species and relatives of crop
plants.
 Germplasm is collected from centers of diversity, gene banks, gene
sanctuaries, farmer’s fields, markers and seed companies.
 Germplasm is the basic material for launching a crop improvement
programme.
 Germplasm may be indigenous (collected within country) or exotic (collected
from foreign countries).

Germplasm Conservation
Germplasm conservation aids in the preservation of knowledge about extinct, wild,
and other living crop plant species because human intervention has eroded genetic
diversity by increasing favored genes and completely eliminating the less desirable,
resulting in the extinction of historic genetic material.

It is primarily concerned with assuring the safe handling and preservation of

germplasm of commercially valuable plants by collecting propagules from each taxon.
Plant breeding and ecosystem habitat regeneration for livestock, horticulture, and forestry
are examples of germplasm protection applications, which include PGRs for food and
agriculture (PGRFA) and PGRs for non-food utilization such as medicinal plant species,
wood and fuel plant species, ornamental species, and recreation and amenity species.

However, the use of available genetic resources for crop development is underutilized.
For each particular crop species, there is a large disparity between actual germplasm
utilization and the number of collections accessible in gene banks. As a result, the goal of
generating enormous germplasm collections is defeated, as plant breeders continue to rely
heavily on fewer and closely related parents and their derivatives in crop development
programs.

One method of generating climate-resilient crops that are better adapted to specific
growing circumstances is to introduce beneficial traits from wild relatives into high yielding
cultivars. Despite the fact that the germplasm accessions appear to be genotypic
duplicates, they are essential instruments for understanding plant development and gene
activities.

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History of Conservation of Plant Genetic Resources

Botanist Alphonse de Candolle was the first to attempt and locate the origin of agricultural plants, and
his study was published as a book named ‘Origin of Cultivated Plants’ in 1882, which was reissued in
1959.
N.I. Vavilov, a Russian explorer, geneticist, and plant breeder, was the first to investigate and
recognize agricultural plant diversity. He established the notion of centers of origin’ of crop plants in
1926, which can be described as a geographical place with the greatest genetic diversity for a crop, and
identified eight unique centers of origin of agricultural plants (1951). He also noticed that the centers of
diversity for some crops did not include their wild relatives, and he explained this pattern as a distinction
between primary center (a geographical region where a crop originated and had maximum diversity) and
secondary center (wild relatives of crops migrated to other places from their centre of origin where they
were domesticated and evolved independently).
Zhukovsky expanded the Vavilovian origin centers into eight mega gene centers of crop variety and
four micro gene centers of crop wild relatives in 1965. However, Harlan (1970) argued that because the
origins of some crops are so dispersed in time and geography, this challenge would never be solved. As a
result, Harlan and De Wet (1971) proposed the concept of gene pools. They classified all genetic diversity
into primary, secondary, and tertiary gene pools based on the degree of relationship between species,
which is less taxonomical but very useful in crop improvement:
1. The primary gene pool (GP1): Crossing among individuals is possible with normal seed set, segregation,
and recombination such that gene transfer is possible through routine breeding. It includes both cultivated
and wild races of a crop.
2. Secondary gene pool (GP2): It includes biological species which have some barriers of crossability with
the crop (GP1), resulting in sterile hybrids, as chromosome pairing is not normal; hence, transfer of genes
is restricted. Overcoming barriers of cross ability can lead to normal seed development.
3. Tertiary gene pool (GP3): More distant to GP2, crosses of GP3 with a crop (GP1) result in lethal or sterile
hybrids due to abnormality in embryo development. Normal gene transfer is not possible but special tissue
culture techniques can be deployed to produce hybrid embryos.

Need for Germplasm Conservation: Genetic Erosion and Genetic Vulnerability

Each crop enhancement programme aims to increase yield, which reduces genetic diversity. Harlan
(1931) described the low diversity of barley. Similarly, Vavilov documented the loss of crop diversity as a
result of current agricultural breeding techniques.

Scientists have been concerned about the loss of genetic diversity since then, and they have
discovered that CWRs and landraces constitute a major source of important variability. Assessing genetic
loss in cereals resulted in the conclusion that cultivated crops were less diversified following domestication
as a result of selection pressures and dispersal bottlenecks.

Genetic erosion, according to Guarino, is the “loss of individual genes or combinations of genes, such
as those found in locally adapted landraces, over time in a given region, and persistent reduction of
common localized alleles”.
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According to the definition, the amount and frequency of depletion of locally adapted particular alleles
is a significant event in genetic erosion. When geographical diversity declines, the entire gene pool
becomes more vulnerable to depletion and extinction, resulting in a reduction in global equality and wealth.

The key causes of genetic erosion, according to the FAO, are direct replacement of local varieties,
overexploitation of species, overgrazing, reduced fallow and changing agricultural systems, indirect land
clearing, population pressure, environmental degradation, legislation/policy change, pest/weed/disease
infestation, civil strife, and climate change, which makes PGRs more vulnerable to extinction.

Plant species are also considered endangered as a result of abrupt changes in environmental
conditions. They are either scarce or on the verge of extinction. It has been reported that approximately
12.5 per cent (34,000 species) of vascular plants globally are threatened.

Methods of Germplasm Conservation

There are two important methods of germplasm conservation or preservation. i) In situ conservation
and ex situ conservation. These are described below.

i) In situ Conservation
Conservation of germplasm under natural conditions is referred to as in situ conservation. This is
achieved by protecting the area from – human interference, such an area is often called natural park,
biosphere reserve or gene sanctuary. NBPGR, New Delhi, established gene sanctuaries in Meghalaya for
citrus, north Eastern regions for musa, citrus, oryza and saccharum.
Gene sanctuaries offer the following advantage.

Merits
In this method of conservation, the wild species and the compete natural or seminatural ecosystems
are preserved together.
Demerits
o Each protected area will cover only very small portion of total diversity of a crop species; hence
several areas will have to be conserved for a single species.
o The management of such areas also poses several problems.
o This is a costly method of germplasm conservation.
ii) Ex situ Conservation
It refers to preservation of germplasm in gene banks. This is the most practical method of germplasm
conservation. This method has following advantages.
 It is possible to preserve entire genetic diversity of a crop species at one place.
 Handling of germplasm is also easy.
 This is a cheap method of germplasm conservation.
This type of conservation can be achieved in the following 5 ways.

1. Seed Banks
Germplasm is stored as seeds of various genotypes. Seed conservation is quite easy, relatively safe
and needs minimum space. Seeds are classified, on the basis of their storability into two major groups.
1) Orthodox and 2) Recalcitrant

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1. Orthodox seeds: Seeds which can be dried to low moisture content and stored at low
temperature without losing their viability for long periods of time is known as orthodox seeds. (e.g.) Seeds
of corn, wheat, rice, carrot, papaya, pepper, chickpea, cotton, sunflower.

Figure 2: Orthodox Seeds and Recalcitrant Seeds.

2. Recalcitrant: Seeds which show very drastic loss in viability with a decrease in moisture content
below 12 to 13 per cent are known as recalcitrant seeds. (e.g.) citrus, cocoa, coffee, rubber, oilpalm,
mango, jack fruit etc.
Seed storage: Based on duration of storage, seed bank collects are classified into three groups. (1)
Base collections. (2) Active collections and (3) Working collection.
1. Base collections: Seeds can be conserved under long term (50 to 100 years), at about -20 oC
with 5 per cent moisture content. They are disturbed only for regeneration.
2. Active collection: Seeds are stored at 0oC temperature and the seed moisture is between 5
and 8 per cent. The storage is for medium duration, i.e.., 10-15 years. These collections are
used for evaluation, multiplication, and distribution of the accessions.
3. Working collections: Seeds are stored for 3-5 years at 5-10 oC and the usually contain about
10 per cent moisture. Such materials are regularly used in crop improvement programmes.
2. Plant Bank
(Field or plant bank) Clonally propagated crops and their wild relatives belong to some 34 plant
families, including herbs, shrubs, trees and vines. Agronomically important genotypes that were selected
over centuries for their specific properties can only be conserved in a vegetative mode.

Consequently, the simplest and most traditional way to establish a collection is to gather specific
genotypes from farmers’ fields, gardens or in the wild and then grow them in the field gene banks where
they continue to grow when maintained appropriately. Even under the highest standards of management,
germplasm maintained in the field can deteriorate due to a wide variety of climate conditions, ageing of the
plants, diseases and pests, hence the need for timely regeneration.

For example, depending on the rootstock and orchard conditions, apple (Malus sp.) trees may need to
be repropagated periodically after 25–50 years The largest field genebanks are located in the USA (potato,

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sweet potato and apple), Japan (apple, citrus and sweet potato), Russia (potato and apple) and Brazil
(citrus and coffee).

Limitations
1. Require large areas

2. Expensive to establish and maintain

3. Prone to damage from disease and insect attacks

4. Man – made

5. Natural disasters

6. Human errors in handling

3. Shoot Tip Banks

Germplasm is conserved as slow growth cultures of shoot-tips and node segments. Conservation of
genetic stocks by meristem cultures has several advantages as given below.
 Each genotype can be conserved indefinitely free from virus or other pathogens.
 It is advantageous for vegetatively propagated crops like potato, sweet potato, cassava etc.,
because seed production in these crops is poor
 Vegetatively propagated material can be saved from natural disasters or pathogen attack.
 Long regeneration cycle can be envisaged from meristem cultures.
 Regeneration of meristems is extremely easy.
 Plant species having recalcitrant seeds can be easily conserved by meristem cultures.
Cell and organ banks: A germplasm collection based on cryopreserved (at – 196 oC in liquid nitrogen)
embryogenic cell cultures, somatic/zygotic embryos they be called cell and organ bank.
DNA banks: In these banks, DNA segments from the genomes of germplasm accessions are
maintained and conserved.

Figure 11.3: Schematic Outlines of Germplasm Conservation Approaches.

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Germplam evaluation: Evaluation refers to screening of gemplasms in respect of morphological,

genetical, economic, biochemical, physiological, pathological and entomological attributes. Evaluation of
germplasm is essential from following angles.
 To identify gene sources for resistance to biotic and abiotic stresses, earliness, dwarfness,
productivity and quality characters.
 To classify the germplasm into various groups
 P To get a clear picture about the significance of individual germplasm line.

IPGRI, Rome has developed model list of descriptors (characters) for which germplasm accessions of
various crops should be evaluated. The evaluation of germplasm is done in three different places viz., (1) in
the field (2) in green house a) 3) in the laboratory.
Germplasm cataloguing, Data storage and Retrieval: Each germplasm accession is given an
accession number. This number is pre fixed in India, with either IC (Indigenous collection), EC (exotic
collection) or IW (Indigenous wild). Information on the species and variety names, place of origin,
adaptation and on its various feature or descriptors is also recorded in the germplasm maintenance
records.

Catalogues of the germplasm collection for various crops are published by the gene banks. The
amount of data recorded during evaluation is huge. Its compilation, storage and retrieval is now done using
special computer programs.

National Bureau of Plant Genetic Resources (nBPGR)

NBPGR establishment in 1976 is the nodal organization in India for planning, conducting, promoting,
coordinating and lending all activities concerning plant.
Collection: Exploration is the collection of germplasm, or the gathering of varied genetic materials from
several sources and storing them in one location, which is a highly scientific technique. Collection can
occur from five different sources: diversity centers, gene banks or sanctuaries, seed collection firms, and
lastly fields.

Second, germplasm collection is done based on endangerment, which means that species or crops
that are on the verge of extinction are prioritized above others. The collection process is carried out in the
presence of agricultural universities in partnership with the National Bureau of Plant Genetic Resources in
New Delhi.

Exchange
The collection is based on migration to locations with higher genetic diversity, visiting the gene bank on
your own, and lastly exchanging genetic material. Similarly, there are two techniques for germplasm
exchange: random sampling, which involves the collection of genetic traits for both biotic and abiotic
challenges, and abiotic, which involves the collection of various phenotypically traits.

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Evaluation
The inquiry or analysis of plant genetic resources based on their phenotypic, genetic, economic,
biological, and chemical features is referred to as evaluation. It is critical for identifying resources for
resistance, productivity, yield, and other quantitative properties.

It contains all of the necessary information for germplasm classification and characterisation of each
particular germplasm attribute. A team of professionals from physiology, biotechnology, biochemistry, and
entomology is required. All of the characters’ evolution is done individually by IPGR experts in Italy.

Evolution takes place in the field, the laboratory, or the greenhouse. The characters of resistance and
biotic or abiotic stresses are screened in the greenhouse, while the evaluation of biochemical characters is
done on the basis of laboratory conditions, using both visual and instrumentation.

Documentation
Documentation entails storing, analysing, and dimensioning. The collection, evolution, storage, and
conservation of information are all aspects of in-plant genetic resources.

However, it is now referred to as an information system. There is a wealth of information available for
main crops such as maize, sorghum, wheat, and rice, among others. Approximately 7.6 million germplasm
samples are currently accessible for the conservation of 300 or more species.

massive collection is managed with the help of electronic technology. In IPRGI, standard characters
and other descriptors for comparison are used to ensure consistency of attributes. The information is stored
in the memory of a computer and must be accessible when needed.

Safe Conservation
Conservation is the safeguarding of plant crop genetic variety against genetic degradation, which can
occur either ex-situ or in situ. In situ conservation refers to conservation in natural habitats that necessitates
the establishment of biosphere or ecosystem resources for the preservation of endangered crops or plants
for future use.

This strategy conserves both wilds and natural biospheres, but it has the disadvantage of covering a
relatively small region of genotype in the case of single species, it is a much more expensive methodology,
and it also necessitates a suitable management system.

Ex-situ conservation germplasm is saved in the form of a gene bank, which is a very practical
application used in laboratories. This technology allows for the preservation of all genetic diversity in one
location.

Sustainable Management of Germplasm

Vegetable Crop Responsibilities and Germplasm Activities at nBPGR

The vegetable crop germplasm programmed broadly includes the following vegetable crops for
evaluation, documentation and maintenance of active collections besides their long-term storage:

1. Solanaaceous Brinjal, tomato, chilies

2 Cucurbitaceous Vegetables Pumpkin, melons, gourds
. and cucumber
3 Leguminous vegetables Cowpea, pea, lablab
. bean, winged bean, faba
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bean, French bean

4 Bulb crops Garlic, onion
.
5 Root vegetables Radish, carrot, turnip
.
6 Okra -
.
7 Miscellaneous vegetables Cole crops, Chinese
. cabbage, spinach beet,
spinach

The quantum of variability available and of diversity of various vegetable crops shows that India is one
of the important centers/regions of variability of vegetable crops. The center of origin/diversity of various
vegetable crops reveals that a number of vegetable crops of economic importance and their wild relatives
originated in this region.
These genetic resources possess genes for wide adaptability, high yield potential including
resistance/tolerance to biotic and abiotic stresses. The Indian sub-continent, thus holds prominence as one
of the twelve regions of variability in crop plants in global perspective.

Gene Banks for Various Crops in India

Institutes Crops
Central Institute for Cotton Research, Nagpur Cotton
Central Plantation crops Research Institute, Kasargod Plantation crop
Central Potato Research Institute, Simla Potato
Central tobacco research Institute, Rajahmundry Tobacco
Central tuber crops research Institute, Thiruvananthapuram Tuber crops other
than potato
Central Rice Research Institute, Cuttack Rice
Directorate of Oilseeds research, Hyderabad Oilseeds
Directorate of Wheat Research, Karnal Wheat
Indian Agricultural Research Institute, New Delhi Maize
Indian Grassland and Fodder Research Institute, Jhansi Forge and fodder
crops
National research centre for sorghum, Hyderabad Sorghum
International Crops Research Institute for Semi-Arid Tropics Groundnut, Pearl
millet, Sorghum,
Pigeon pea and
Bengal gram

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List of Important International Institutes Conserving Germplasm

Name Institute Activity
IRRI International Rice Research Tropical rice
Institute, Los Banos, Philippines Rice collection: 42,000
CIMYT Centre Inter national de- Maize and wheat
Mejoramients de maize Trigo, El (Triticale, barely,
Baton, Mexico sorghum) Maize
collection – 8000
CIAT Center International de- Cassava and beans,
agricultural Tropical Palmira, (also maize and rice) in
Columbia collaboration with
CIMMYT and IRRI
IITA International Institute of Tropical Grain legumes, roots,
Agriculture, Ibadan, Nigeria. and tubers, farming
systems.
CIP Centre International de-papa- Potatoes
Lima. Peru
ICRISAT International Crops Research Sorghum, Groundnut,
Institute, for Semi-Arid Tropics, Cumbu, Bengalgram,
Hyderabad, India Redgram.
WARDA West African Rice Development Regional Cooperative
Association, Monrovia, Liberia Rice
Research in
Collaboration with IITA
and IRRI
IPGRI International Plant Genetic Genetic conservation.
Research Institute, Rome Italy
AVRDC The Asian Vegetable Research Tomato, Onion,
and Development Centre, Taiwan Peppers Chinese
cabbage.

References
1. Wilkes, G. In Situ Conservation of Agricultural Systems. In Biodiversity; Culture, Conservation and Eco
Development; Oldfield, M., Alcorn, J., Eds.; West View Press: Boulder, CO, USA, 1991; pp. 86–101.
2. Rao, N.K. Plant genetic resources: Advancing conservation and use through biotechnology. Afr. J.
Biotechnol. 2004, 3, 136–145.
3. Baute, G.J.; Dempewolf, H.; Rieseberg, L.H. Using genomic approaches to unlock the potential of CWR for
crop adaptation to climate change. In Crop Wild Relatives and Climate Change; Redden, R., Yadav, S.S.,
Maxted, N., Dulloo, M.E., Guarino, L., Smith, P., Eds.; Wiley Blackwell: Hoboken, NJ, USA, 2015.
4. Kell, S.; Marino, M.; Maxted, N. Bottlenecks in the PGRFA use system: Stakeholders’ perspectives.
Euphytica 2017, 213, 170.

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5. Fao/Ipgri/Onu. Genebank standards for Plant Genetic Resources for Food and Agriculture, Rev. ed.; FAO:
Rome, Italy, 2014; p. 182. ISBN 9290432365.
6. Gosal, S.S.; Wani, S.H.; Kang, M.S. Biotechnology and crop improvement.
J. Crop. Improv. 2010, 24, 153–217.
7. De Wet, J.M.J. Cereals for the semi-arid tropics. In Plant Domestication by Induced Mutation, Proceedings
of the Advisory Group Meeting on The Possible Use of Mutation Breeding for Rapid Domestication of New
Crop Plants, Vienna, Austria, 17–21 November 1986; Joint FAO/IAEA Division of Nuclear Techniques in
Food and Agriculture: Rome, Italy, 1989; pp. 79–88.
8. Wright, B.D. Crop genetic resource policy: The role of ex situ gene banks. Aust. J. Agric. Resour. Econ.
1997, 41, 81–115.
9. Upadhyaya, H.D.; Gowda, C.L.L.; Buhariwalla, H.K.; Crouch, J.H. Efficient use of crop germplasm
resources: Identifying useful germplasm for crop improvement through core and mini-core collections and
molecular marker approaches. Plant Genet. Resour. 2006, 4, 25–35.
10. Debouck, D.G. Managing Plant Genetic Diversity. Crop Sci. 2003, 43, 749–750.
11. Vavilov, N.I. Origin and Geography of Cultivated Plant; Cambridge University Press: Cambridge, UK, 1992;
ISBN 0521404274.
12. Zhukovsky, P.M. Main gene centres of cultivated plants and their wild relatives within the territory of the
U.S.S.R. Euphytica 1965, 14, 177–188.
13. Harlan, J.R.; De Wet, J.M.J. Toward a Rational Classification of Cultivated Plants. Taxon 1971, 20, 509–
517.
14. Harlan, H.V. The Origin of Hooded Barley. J. Hered. 1931, 22, 265–272.
15. Martos, V.; Royo, C.; Rharrabti, Y.; Garcia Del Moral, L.F. Using AFLPs to determine phylogenetic
relationships and genetic erosion in durum wheat cultivars released in Italy and Spain throughout the 20th
century. Fields Crop. Res. 2005, 91, 107–116.
16. Rocha, F.; Bettencourt, E.; Gaspar, C. Genetic erosion assessment through the re-collecting of crop
germplasm. Counties of ArcodeValdevez, Melgaço, Montalegre, Ponte da Barca and Terras de Bouro
(Portugal). Plant Genet. Resour. Newsl. 2008, 154, 6–13.
17. Ruiz, M.; Rodriguez-Quizano, M.; Metakovsky, E.V.; Vazquez, J.F.; Carrillo, J.M. Polymorphism, variation
and genetic identity of Spanish common wheat germplasm based on gliadins alleles. Field Crops Res.
2002, 79, 185–196.
18. Ross-Ibarra, J.; Morrell, P.L.; Gaut, B.S. Plant domestication, a unique opportunity to identify the genetic
basis of adaptation. Proc. Acad. Natl. Sci. USA 2007, 104 (Suppl. 1), 8641–8648.
19. Guarino, L. Approaches to measuring genetic erosion. PGR Documentation and Information in Europe—
Towards a sustainable and user-oriented information infrastructure. In Proceedings of the EPGRIS Final
Conference Combined with a Meeting of the ECP/GR Information and Documentation Network, Prague,
Czech Republic, 11–13 September 2003.
20. Upadhyaya, H.D.; Gowda, C.L.L. Managing and Enhancing the Use of Germplasm—Strategies and
Methodologies; Technical Manual No. 10; ICRISAT: Patancheru, India, 2009.
21. Brodie, J.F.; Aslan, C.E.; Rogers, H.S.; Redford, K.H.; Maron, J.L.; Bronstein, J.L.; Groves, C.R. Secondary
Extinctions of Biodiversity. Trends Ecol. Evol. 2014, 29, 664–672.

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