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 Background
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Title: Wellhausen-Anderson Plant Genetics Resource Center operations manual 2004
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Title: Wellhausen-Anderson Plant Genetics Resource Center operations manual 2004
Physical Description: Book
Language: English
Creator: International Maize and Wheat Improvement Center (CIMMYT)
Publisher: International Maize and Wheat Improvement Center (CIMMYT)
Publication Date: 2004
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Subject: Caribbean   ( lcsh )
Farming   ( lcsh )
Spatial Coverage: Caribbean
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Bibliographic ID: UF00077500
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
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Table of Contents
    Front Cover
        Front cover
    Title Page
        Page i
    Copyright
        Page ii
    Table of Contents
        Page iii
    Preface
        Page iv
    Background
        Page 1
        Description of maize and related species
            Page 1
            Page 2
            Page 3
        Description of wheat and related species
            Page 4
            Page 5
            Page 6
        History of CIMMYT's gene bank
            Page 7
        International laws / agreements that affect genetic resources
            Page 8
            Page 9
    Germplasm bank operations
        Page 10
        Physical infrastructure
            Page 10
        New introduction/accessions to the maize and wheat collections
            Page 10
            Page 11
            Page 12
            Page 13
        Seed viability and germination tests
            Page 14
        Regeneration of introductions / accessions
            Page 15
            Page 16
            Page 17
        Evaluation of maize and wheat accessions
            Page 18
            Page 19
        Shipments
            Page 20
        Back-up collections
            Page 21
        Data management
            Page 22
        References
            Page 23
            Page 24
Full Text



We a ae *adeso
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Wel Ihausen-Anderson
Plant Genetic Resources Center

Operations Manual 2004











II CIMMYTMR























































CIMMYT (www.cimmyt.org) is an internationally funded, not-for-profit organization that conducts research
and training related to maize and wheat throughout the developing world. Drawing on strong science and
effective partnerships, CIMMYT works to create, share, and use knowledge and technology to increase food
security, improve the productivity and profitability of farming systems, and sustain natural resources.
Financial support for CIMMYT's work comes from many sources, including the members of the Consultative
Group on International Agricultural Research (CGIAR) (www.cgiar.org), national governments, foundations,
development banks, and other public and private agencies.

International Maize and Wheat Improvement Center (CIMMYT) 2004. All rights reserved. The designations
employed in the presentation of materials in this publication do not imply the expression of any opinion
whatsoever on the part of CIMMYT or its contributory organizations concerning the legal status of any
country, territory, city, or area, or of its authorities, or concerning the delimitation of its frontiers or
boundaries. CIMMYT encourages fair use of this material. Proper citation is requested.

Correct citation: Taba, S., M. van Ginkel, D. Hoisington, and D. Poland. 2004. Wellhausen-Anderson Plant
Genetic Resources Center: Operations Manual, 2004. El Batan, Mexico: CIMMYT.











Contents






Contents ....................................................................................................................................................................... iii

Preface .......................................................................................................................................................................... iv

I. Background ............................................................................................................................................................... 1
A D description of M aize and Related Species ...................................................................................... 1
A.1. Importance of maize for global food security and research ........................... .......... 1
A .2. Origin of the m aize ...................................................................................................................
A .3. Centers of diversity ................................................................................... ............................ 4

B. D description of W heat and Related Species ............................................................................................4
B.1. Importance of wheat for global food security and research........................... ........... 4
B.2. O rigin of the w heat ............................................................................. .................................. 5
B.3. Centers of diversity ................................................................................... ............................ 6

C. H history of CIM M YT's G erm plasm Bank ................................................................................................ 7
C.. M aize ........................................................................... ....................... ......................... 7
C.2. W heat ...................... .......................................................................................................... 8
C.3. Wellhausen-Anderson Plant Genetic Resources Center ............................. ............ 8

D. International Laws/Agreements that Affect Genetic Resources ................................... ............. 8

II. G enebank O operations ................................................................................................................................... 10
A Physical Infrastructure ............................................................................................................................. 10

B. New Introductions/Accessions to the Maize and Wheat Collections .............................................10
B.1. M aize: guiding principles for new introductions ..................................................... 10
B.2. W heat: guiding principles for new introductions ................................... .................. 11
B.3. Introduction of new m materials ............................................ ......................................... 11

C. Seed Viability and G erm nation Tests ............................................................................................ 14

D Regeneration of Introductions/A ccessions .......................................................................................... 15
D .. M aize regeneration .................................................................................... ......................... 15
D .2. Teosinte regeneration.................................................................................. ........................ 17
D .3. Tripsacum regeneration .............................................................................. ......................... 17
D .4. W heat regeneration................................................................................. ........................... 17

E. Evaluation of M aize and W heat A ccessions ................................................................................... 18

Shipm ents .................................................................................................................................................... 20
F .1 M a iz e ...................... .......................................................... ................... ........ .................... 2 0
F .2 W h e at ..................... .................................................. .......................... .. ...... .............. ..... 2 0

G Back-up Collections ........................................................................................................................... 21
G .1. M aize ........................................................... ....................................... ........................ 21
G .2. W heat .......................................................... ........................................ ........ ................... 22

H D ata M anagem ent ..................................................................................................................................... 22
H M a iz e ...................................................................................................... .......... ........ ..... 2 2
H .2. W heat ........................................................... ... ........................ ... ..... ................... 22

I. References .................................................................................................................................................... 23










Preface





In 2004, CIMMYT restructured its research programs into six new global and ecoregional programs. One of
these, the Genetic Resources Program, is now home to the maize and wheat germplasm collections in
CIMMYT's gene bank. This new organizational structure indicates the high importance and visibility that
CIMMYT places on our role as custodians of maize, wheat, and related species genetic resources.

One of the first priorities of the program was to update the operations manual for the gene bank. The result of
this effort is this publication, the Wellhausen-Anderson Genetic Resources Center Operations Manual. Many staff
contributed to this version that was ultimately assembled and edited by Suketoshi Taba, maize germplasm
collection manager, Maarten van Ginkel, wheat germplasm collection manager, David Poland, senior writer/
editor, and Dave Hoisington, Genetic Resources Program Director.

The policies and procedures outlined in the manual represent those currently being used in the introduction,
evaluation, maintenance, regeneration, and distribution of genetic resources at CIMMYT. By following these
procedures, CIMMYT ensures that the genetic resources entrusted to it in its germplasm collections are
available to the world and that they maintain their genetic integrity while under CIMMYT's custodianship.

CIMMYT will continue to evaluate and update these policies and procedures. This is especially critical as new
legal requirements come into force, such as the International Treaty of Plant Genetic Resources for Food and
Agriculture, and other aspects of gene bank management come to the fore, such as requirements for
monitoring the presence of transgenes.










I. Background






A. Description of Maize and Related Species

A.1. Importance of maize for global food security and research
According to an ancient Indian legend, maize was "the food of the gods that created the Earth." It is scarcely
less important today, as along with wheat and rice, it is one of the world's three most important cereals. Maize
originated in southern Mexico and was first domesticated more than 6,000 years ago. Its cultural significance to
the region is similar to that of rice to Asia and wheat and barley to the Middle East. Maize exists only as a
cultivated crop, because the seeds cannot be separated from the cob without human intervention.

By 2020, the demand for maize in developing countries is projected to surpass the demand for both wheat
and rice. This is reflected in a 50% increase in global maize demand from 558 million tons in 1995 to a
projected 837 million tons in 2020. In the developing world alone, maize demand will increase from 282
million tons in 1995 to a projected 504 million tons in 2020.

Approximately 140 million hectares of maize is cultivated globally. The main producers are the USA,
China, and Brazil, followed by Argentina, South Africa, and the EU. Approximately 96 million hectares are
grown in developing countries with four countries (China, Brazil, Mexico, and India) accounting for more
than 50% of the total.

Although used primarily for animal feed (78%), mainly for cattle, pigs, and poultry, 13% is used as food for
humans, where its applications are diverse. It is eaten, for example, as corn on the cob or polenta, or in
processed forms such as oil, starch, sweeteners, and flour. Such is its versatility that its derivatives can also be
found in drugs like aspirin and antibiotics, in cosmetics and soaps, and in a broad range of industrial products.

Maize has been a major focus of genetic and biotechnology research for several reasons. The presence of
hybrid technology and its commercial importance enables the private sector to capitalize on the sale of
hybrid seed and derive benefits from their investments in research and development.

In addition to commercial benefits, maize also offers a number of significant scientific advantages. Classical
genetic studies have evolved to the point that the collection of known loci and genetic/ cytogenetic stocks are
enormous. This, coupled with the ease with which many molecular studies-both genetic and biological-
can be accomplished has lead to a wealth of investigations and will ultimately lead to an in-depth
understanding of the maize genome. Efforts to develop the tools and techniques for expanded identification
of genes and gene functions via modern genomics promise to maintain the position of maize as a lead genetic
organism, while providing powerful approaches for enhancing maize productivity.

A.2. Origin of maize
Maize is believed to have originated in southern Mexico. Many studies have been made on maize evolution
and domestication using archaeological evidence, maize landrace diversity, the natural habitats of the close
relatives of teosinte and Tripsacum, maize culture in Mexico and Guatemala, and molecular genetics and
evolution. Maize was domesticated more than 6,000 years ago in Tehuacan, Puebla, Mexico and became the
dietary staple about 3,500 years ago. The Tehuacan cob specimens, by new measurement, date back 5,500
years without showing introgression of teosinte characteristics, but with the pistillate spikelets below and the
staminate spikelets at the tip of the ear (a bisexual condition). Later Tehuacan specimens indicate that about










I. Background






A. Description of Maize and Related Species

A.1. Importance of maize for global food security and research
According to an ancient Indian legend, maize was "the food of the gods that created the Earth." It is scarcely
less important today, as along with wheat and rice, it is one of the world's three most important cereals. Maize
originated in southern Mexico and was first domesticated more than 6,000 years ago. Its cultural significance to
the region is similar to that of rice to Asia and wheat and barley to the Middle East. Maize exists only as a
cultivated crop, because the seeds cannot be separated from the cob without human intervention.

By 2020, the demand for maize in developing countries is projected to surpass the demand for both wheat
and rice. This is reflected in a 50% increase in global maize demand from 558 million tons in 1995 to a
projected 837 million tons in 2020. In the developing world alone, maize demand will increase from 282
million tons in 1995 to a projected 504 million tons in 2020.

Approximately 140 million hectares of maize is cultivated globally. The main producers are the USA,
China, and Brazil, followed by Argentina, South Africa, and the EU. Approximately 96 million hectares are
grown in developing countries with four countries (China, Brazil, Mexico, and India) accounting for more
than 50% of the total.

Although used primarily for animal feed (78%), mainly for cattle, pigs, and poultry, 13% is used as food for
humans, where its applications are diverse. It is eaten, for example, as corn on the cob or polenta, or in
processed forms such as oil, starch, sweeteners, and flour. Such is its versatility that its derivatives can also be
found in drugs like aspirin and antibiotics, in cosmetics and soaps, and in a broad range of industrial products.

Maize has been a major focus of genetic and biotechnology research for several reasons. The presence of
hybrid technology and its commercial importance enables the private sector to capitalize on the sale of
hybrid seed and derive benefits from their investments in research and development.

In addition to commercial benefits, maize also offers a number of significant scientific advantages. Classical
genetic studies have evolved to the point that the collection of known loci and genetic/ cytogenetic stocks are
enormous. This, coupled with the ease with which many molecular studies-both genetic and biological-
can be accomplished has lead to a wealth of investigations and will ultimately lead to an in-depth
understanding of the maize genome. Efforts to develop the tools and techniques for expanded identification
of genes and gene functions via modern genomics promise to maintain the position of maize as a lead genetic
organism, while providing powerful approaches for enhancing maize productivity.

A.2. Origin of maize
Maize is believed to have originated in southern Mexico. Many studies have been made on maize evolution
and domestication using archaeological evidence, maize landrace diversity, the natural habitats of the close
relatives of teosinte and Tripsacum, maize culture in Mexico and Guatemala, and molecular genetics and
evolution. Maize was domesticated more than 6,000 years ago in Tehuacan, Puebla, Mexico and became the
dietary staple about 3,500 years ago. The Tehuacan cob specimens, by new measurement, date back 5,500
years without showing introgression of teosinte characteristics, but with the pistillate spikelets below and the
staminate spikelets at the tip of the ear (a bisexual condition). Later Tehuacan specimens indicate that about










3,000 years ago there was an explosive change in cob size. The specimens of Guila Naquitz cave, about 5 km
from Mitla, Oaxaca, date back even further, 6,250 years. The cobs of Guila Naquitz cave indicate maize x
teosinte hybridization by its indurated rachis.

The emergence of maize remains scientifically controversial, especially the roles played by teosinte and
Tripsacum in maize evolution and domestication. A recent study of the molecular phylogeny based on the
diversity of maize landraces and teosinte using simple sequence repeats (SSR) suggests a single domestication
of maize, possibly from the race Balsas teosinte (Zea mays L. subsp. parviglumis Iltis and Doebley).

A.2.1. Origin of teosinte
Teosinte is believed to have originated in Mexico and Guatemala. The in-situ populations of teosinte are
found on the Central Plateau and western escarpment of Mexico/Guatemala, in a seasonally dry,
subtropical zone between 500 and 2,200 m with summer rains. Annual teosinte populations are Nobogame,
Durango, Central Plateau, Chalco, Balsas, and Oaxaca in Mexico, and Huehuetenango and Guatemala in
Guatemala. These populations are classified among the teosinte races by Wilkes (1967, 2004). Perennial
teosinte has a tetraploid and a diploid species. Zea perennis (4n) is considered an autotetraploid derived
from Zea diploperennis (2n). Zea diploperennisis and Zea perennis are located respectively in the Sierra de
Manantlan, and Ciudad Guzman, Jalisco, Mexico. The annual teosinte races Guatemala and Huehuetenango
are located in the Departments of Jutiapa, Jalapa, and Chiquimula, and Department of Huehuetenango,
northwestern Guatemala. Iltis and Benz (2000) reported a teosinte population (Zea nicaraguensis Iltis & Benz)
that is differentiated from Zea luxurians and grown in Chinandega, Nicaragua. Teosinte can hybridize with
maize although some teosinte races show cross incompatibility with normal maize genotypes.

A.2.2. Origin of Tripsacum
Mexico and Guatemala are the center of diversity of Tripsacum. Tripsacum species are widely distributed in the
Americas and are numerous in Mexico. The accumulated information on maize-Tripsacum hybrids and their
derivatives indicate that the respective genetic architecture of maize and Tripsacum, although different, are
more similar than their karyotypes would suggest. Maize and Tripsacum diverged long before domestication of
maize. Many genes have homologous counterparts, but the blocks of linked maize genes are spread over
many chromosomes.




Table. CIMMYT gene bank conserves samples of teosinte races from Mexico, Guatemala, and Nicaragua

Formal species and subspecies Evolutionary groupings in Zea and race name Country

Section: Euchlaena (Schrader) Kuntze in Von Post and Kuntze lexicon, 599 (1904)
Zea mays subsp. mexicana (Schrader) Iltis Zea mexicana (Schrader) Kuntze Race Nobogame Mexico
Zea mays subsp. mexicana (Schrader) Iltis Zea mexicana (Schrader) Kuntze Race Central Plateau Mexico
Zea mays subsp. mexicana (Schrader) Iltis Zea mexicana (Schrader) Kuntze Race Chalco Mexico
Zea mays subsp. parviglumis Iltis and Doebly Zea mexicana (Schrader) Kuntze Race Balsas Mexico
Zea Mays subsp. huehuetenangsis Doebly Zea mexicana (Schrader) Kuntze Race Huehuetenango Guatemala

Section: Luxuriantes (Durieu) Bull Soc. Acclimat. 19:581 (1872)
Zea luxurians (Durieu and Ascherson) Bird Zea luxurians (Durieu and Ascherson) Bird Guatemala
Zea perennis (Hitchcock) Reeves and Mangelsdorf Zea perennis (Hitchcock) Reeves & Mangelsdorf Mexico
Zea diploperennis Iltis, Doebley and Guzman Zea diploperennis Iltis, Doebley & Guzman Mexico
Zea nicaraguensis Iltis and Benz. Nicaragua

Reference sources: Wilkes (1967, 2004), Iltis (1972), Bird (1978), Doebley (1980, 1990), Doebley and Iltis (1980), Iltis and Doebley (1980), Sanchez and Ordaz (1987),
and Iltis and Benz (2000).










All taxa of Tripsacum are perennial. Diploid (2n=36) plants are sexual, while higher ploidy levels (triploids,
tetraploids, and pentaploids) are generally apomictic, with fleshy rhizomes. T. zopilotense, the small, narrow-
leaved, xeric-adapted species from the Canon del Zopilote in Guerrro, Mexico lacks rhizomes. Plants can be
recovered from Zea x Tripsacum hybrids through backcrossing, suggesting a possible gene flow between the
two genera.

Tripsacum andersonii, guatemala grass, has 64 chromosomes. It was discovered in Guatemala and spread to
South America to feed guinea pigs. Results of molecular marker experiments at CIMMYT indicate that T.
andersonii was formed by two hybridization events: first between T. latifolium (2x) x T. maizar (2x) that formed
T. latifolium (3x=54 chromosomes) and the subsequent second hybridization between T. latifolium (3x=54 chr) x
Zea luxurians (2n=20) led to the formation of T. andersoni.


A.3. Centers of diversity
Domestication and evolution of maize in southern Mexico and Guatemala (Mesoamerica) and the spread of
maize to North and South America as a staple food crop generated large landrace diversity first encountered
when collections began in earnest during the last 60 years. Goodman (1978), in considering maize in the
Americas, distinguished six large racial complexes of economic importance: the Mexican dents, the Corn Belt
Dents, the Tusons (Caribbean dent), the Caribbean flints, the Northern Flints and Flours, and the Cateto or


Table 2. CIMMYT field germplasm bank conserves clones of Tripsacum from Mexico, Central America, South America, and USA

Species ID No. of Chromosomes Ploidy level Reproduction Country
Tripsacum australe var australe TAA 36 Diploid Sexual Peru, Colombia
72 Tetraploid Apomictic
Tripsacum andersonii TAD 54 Hybrid Sexual Venezuela, Colombia, Peru, Brazil,
Mexico, Honduras, Belize
Tripsacum bravum (Gray) TBV 72 Tetraploid Apomictic Mexico
1 Hexaploid Apomictic
Tripsacum cundinamarca TCD 36 Diploid Sexual Colombia
Tripsacum dactiloides (L.) L. TDD 72 Tetraploid Apomictic USA
Tripsacum dactiloidesvar. hispidum(H) TDH 72 Tetraploid Apomictic Mexico
Tripsacumdactiloidesvar. mexicana TDM 72 Tetraploid Apomictic Mexico
Tripsacum intermedium TIT 72 Tetraploid Apomictic Mexico, Honduras
90 Pentaploid Apomictic
Tripsacumjalapense TJL 72 Tetraploid Apomictic Mexico
Tripsacum lanceolatum TLC 72 Tetraploid Apomictic Mexico, USA
Tripsacum latifolium (Hitchc) TLT 54 Triploid Apomictic Mexico
72 Tetraploid Apomictic
Tripsacum dactiloides var. meridionale TMR 54 Triploid Apomictic Colombia
14 Diploid Sexual Venezuela
Tripsacum maizar (Hern. and Rand.) TMZ 72 Tetraploid Apomictic Mexico
3 Triploid Apomictic
Tripsacum pilosum (Scribner and M) TPL 36 Diploid Sexual Mexico, Belize
4 Tetraploid Apomictic
2 Triploid Apomictic
Tripsacumperuvianum TPR 90 Pentaploid Apomictic Peru, Venezuela, Ecuador
Tripsacum zopilotensis (Herna. And R.) TZP 36 Diploid Sexual Mexico
No name 72 Tetraploid Sexual









Argentine Flints. In addition, the Andean Complex and Amazonian Coroico types are the other groups of
maize races known to contain local racial diversity. Races of maize and their interrelationships are further
described by Goodman and Brown (1988).

CIMMYT preserves maize germplasm accessions from 64 countries (19 in Latin America, 19 in the Caribbean,
11 in Africa, 10 in Asia, 3 in Europe, and 2 in Oceania). The CIMMYT germplasm bank preserves 329 classes of
landraces, some of them are identified with race classifications and others by local common names.




B. Description of Wheat and Related Species

B.1. Importance of wheat for global food security and research
Of the major global cereal staples, wheat is the most widely grown, ranging from sea-level to 4,000 masl, and
from the equator to Norway in the north, and to southern Chile in the south.

Unlike maize, more than 90% of wheat is directly consumed by humans, with little used for livestock feed or
other purposes. Scarcely a person on planet does not eat a wheat product at least once a week, with some
consuming wheat three times a day, providing half, or more, of all calories consumed. Wheat is a major
staple and calorie source for more than half of the world population, and is expected to remain so in the
medium to long term. About 90% of the wheat produced is common wheat or 'bread' wheat (triticum
aestivum), used for diverse leavened breads (e.g., pan-type, steamed) and flat breads (e.g., chapattis, Arabic
flat bread, tortillas), noodles, biscuits (cookies), and other baked products. The remaining 10% is durum
wheat (T. durum or T. turgidum), which is consumed as semolina (coarse grits), pasta, couscous, bulgur, and
local flat breads. One of the fastest growing product categories for common wheat is instant flour noodles in
East and Southeast Asia. Alternate uses such as for starch and glutens are expected to increase.

Projections for 2020 are that wheat area, currently about 210 million hectares, will not increase but may actually
decrease somewhat as yields continue to rise. Of this total, about half the area is located in developing countries.
This change in area planted can be attributed to a portion of developing country farmers moving into crops with
a greater rate of financial return or leaving the farm to find gainful employment in higher paying jobs. China,
today, is a significant case in point.

Presently global production is 560 million tons annually, almost half being produced in developing
countries. Average yield, now at 2.7 t/ha, will need to increase by at least 2% annually to meet higher
demand. Both agronomic and genetic improvements are expected to continue to play key and equal roles in
meeting this challenge.

The major wheat producers are China, Europe taken as a whole, India, USA, Australia, and Canada. Among
developing countries, China, India, and Pakistan plant 60% of the wheat area. The major exporters of wheat are
the USA, European nations, Australia, and Canada, with Kazakhstan also emerging as a potentially major future
exporter. Many small developing countries usually import wheat. Depending on trends towards agricultural and
income diversification, some larger producers, such as China, may return to requiring importation of
considerable amounts of wheat. Part of this can be traced to an economic paradigm shift from the older aim of
'self-sufficiency to the more recently annunciated aim of 'self-reliance' in this age of globalization.

Wheat, despite its genetic complexity, presents considerable potential for the use of molecular markers in the
breeding process, with some programs already using such markers routinely, including CIMMYT's breeding
program. In wheat, molecular relationships tend to hold better across diverse populations and this consistency
increases their reliability and wider application. Work on transgenic wheat has been limited globally, with no
known transgenic wheat being commercially released and grown.









Due to its polyploid nature, wheats can survive the absence, addition, or substitution of entire chromosomes
and translocations of parts of chromosomes. This has allowed the development of unique sets of genetic
stocks since the middle of the 20 century. These genetic stocks have allowed the location and manipulation of
genes responsible for minor and major traits through the use of biotechnological and cytogenetic tools. With
recent crosses involving modern commercial durum wheats tetraploidd) and Aegilops tauschii diploidd),
common wheat (hexaploid) can be reconstructed into what are essentially 'remixes' of wheat, which are
known under various names. These remix wheats have greatly expanded potential diversity in wheat.

Genetic diversity is critical to enhancing and stabilizing yield potential as well as sustaining that potential
through new sources of resistances and tolerances to biotic and abiotic stresses. Thus, genetic resources are
fundamental to sustaining wheat production in the future.

Wheat cultivars up to the 1950s were an assembly of gene combinations pyramided over the last century by
breeders using, in most cases, well-adapted cultivars from within their own region with rare imports from
outside (e.g., introduction in the early 1900s of Japanese semi-dwarf wheat into Strampelli's program in Italy;
1920s the introduction of Strampelli's wheats into Argentina; introduction of two dwarfing genes originating
from the Japanese cultivar NORIN 10 into the Mexican Office of Special Studies program led by Norman E.
Borlaug in the early 1950s, via cross progeny made by Vergil Vogel at the Washington State University in
Pullman, Washington, USA).

The advance of international agriculture since the mid 20th century enormously expanded the global
availability of germplasm from more diverse sources, thus significantly changing patterns of cross
hybridization and cultivar release and distribution. The Green Revolution showed how use of introduced
germplasm either directly or in crosses could provide significant increases in genetic diversity expressed in
yield and disease resistance. By the early 1970s a rapid release of cultivars to farmers in particular in
developing countries occurred that were derived directly or indirectly from external breeding programs. This
spread of new cultivars was associated with an equally rapid replacement of the local cultivars, which
resulted in a large and concerted effort to collect remaining local germplasm.

Gene bank modus operandi sufficed until the recent past to 'collect and cool' such latent diversity. Now that,
especially in the case of wheat, the collection of most important local landraces has apparently been achieved,
modern ways need to be explored to identify and unlock the genetic diversity held in these sub-zero genebank
storage rooms and in in situ collections. In particular where the number of accessions held is high, such as in
the CIMMYT wheat collection, biotechnological tools in concert with GIS approaches will be needed to locate
the rare gems within the collections.

CIMMYT's major objectives include increasing farm-level productivity while safe-guarding against genetic
vulnerability, and through this, enhancing livehoods of the resource poor. The preservation, documentation,
evaluation, enhancement, and easy accessibility of genetic resources are central to those ends.

B.2. Origin of wheat
Genetic analyses prove beyond a doubt that wheat is a very young crop with paradoxically, one of the broadest
and one of the narrowest of foundations. Still it is the most widely grown crops on the Earth. About 10-12,000
years ago, two diploid grasses (one each from the Sitopsis group and the Triticum uratu species) crossed and
formed two of the three legs of modern wheat. Such crosses between distinct grasses are very rare and tend to
lead to infertile progeny. The two parents of the resulting tetraploid wheat are from somewhat related species
but not overly close. The progeny is generally sterile. Occasionally and spontaneously chromosomes in young
progeny from a cross between these two grasses double thus leading to a fertile descendant (with twice the
chromosome number of either of its parents: 2x14 = 28 a tetraploid), which can produce fertile offspring of its
own. Years pass and fortunately a fertile progeny of yet another cross between two grass individuals from within
each of the Sitopsis genus and the Triticum uratu species results in fertile progeny (known as Triticum dicoccoides).
Thus early wheat was introduced to domestic life and itself domesticated.










Three problems were directly noted by early humans: the seeds of the spike separated even before the plant
fully matured and fell straight to the ground, a prey for birds and rodents. The seed was also fused to the outer
leaves (a.k.a. glumes, not unlike in the case of barley) and was difficult to separate from the glumes during
threshing. Finally, while a sufficient number of seeds were planted the following year to produce a good stand
of plants, only a proportion actually germinated and formed plants, which for wild grasses is a good risk
avoidance strategy, but is undesirable in cultivated crops.

Domestication is essentially humans looking out for their favored plants and dealing with such threats as dry
conditions (e.g., by building irrigation works in lower Egypt), competition by other grasses (i.e., through
weeding), or threshing in the safety of a compound. Within one thousand years, according to some estimates,
minor deviations or mutations of the spikes within the young wheat crop were noted where the seeds did not
separate on their own (i.e., non-brittle rachis), seeds that did not adhere to the glumes (i.e., free-threshing), and
seeds that germinated pretty much all at the same time (i.e., uniform dormancy). Thus the young wheat was
transformed during domestication to essentially a distinct species known as Triticum dicoccum or emmer wheat.

The young emmer wheat was popular and spread from its ancestral region, the northern Fertile Crescent, to
the southwest and east. Over time it evolved to what we now know as Triticum durum or Triticum turgidum, our
modern durum wheat used to make pasta products. About 8,000 years ago, in what is now Iran, a third grass
known in some areas as goat grass (Aegilops tauschii) crossed with the young Triticum dicoccum crop to produce
the fertile progeny now known as Triticum aestivum, or common bread wheat. Domestication continued and
through the appearance of, for example, spelt wheats, modern bread wheat emerged alongside durum wheat.
Wheat then has a broad base in that three distinct grasses intercrossed to form its early progenitors, though in
some terms also a narrow base in that modern wheats likely trace back to just very few individual plants that
contributed their genes within each of these three grasses.


B.3. Centers of diversity
Wheat originated in various steps in the Fertile Crescent, as described in the section on 'Origin.' From there it
move rapidly south, though initially not far beyond Ethiopia, at which point its spread southward slowed
considerably (wheat was not introduced into South Africa until the mid 17th century.); east (to India and China)
and west/northwest (to the Mediterranean region and Europe). By 4000-2000 B.C., these regions had acquired
wheat introductions, represented by various diploid, tetraploid and hexaploid forms. Only in the early and
mid 16th century was wheat introduced to the Americas, and in the late 18th century to Australia.

Some examples of centers of diversity of early wheat Table 3. Domesticated and cultivated wheats and their relatives held
relatives are in the CIMMYT wheat collection. Notation modified from Kimber and
Sears (1987), Feldman (2001) and Gill and Friebe (2002)


* T. monococcum, still grown for animal feed in the
mountainous regions of Turkey, Yugoslavia,
southern Italy and Daghestan (Central Asia);
* T. dicoccoides and various other early tetraploids,
found in Ethiopia, India, Iran, Transcaucasia, the
Mediterranean basin, eastern Turkey, and the
Balkans;
* Ae. tauschi, grown in the Caucasus, Trancaucasia,
Central Asia, Afghanistan, China (Himalaya),
India (Kashmir), Pakistan, Iran, Iraq, and eastern
Turkey; and
* T. aestivum early relatives such as T. aestivum ssp.
sphaerococcum and others, still grown in parts of
India, Pakistan, Afghanistan (Hindu-Kush region)
and Trancaucasia.


(Sub)species Common name Genome
Triticum monococcums pp
spp. aegilopoidess pp Wild einkorn AM
spp. monococcum Cultivated einkorn or small spelt AM
l urartu (wild form) A
. boeoticum (wild form) A
. timopheevii Timopheevii A'G
. turgidumspp
spp. dicoccoides Wild emmer AB
spp. dicoccon (syn. dicoccum) Cultivated emmer AB
spp. durum Macaroni or hard wheat AB
spp. polonicum Polish wheat AB
spp. carthlicum Persian wheat AB
. aestivum
spp. spelta Dinkel or large spelt ABD
spp. aestivum Common or bread wheat ABD
spp. compactum Club wheat ABD
spp. sphaerococcum Indian dwarf or shot wheat ABD










Table 4. Aegilops species held in the CIMMYT wheat collection.
Notation modified from Kimber and Sears (1987), Feldman (2001)
and Gill and Friebe (2002)

(Sub)species Genome

Aegilops bicornis Sb
Ae. biuncialis UM (UMo)
Ae. caudata C
Ae. columnaris UM (UX.)
Ae. comosa M
Ae. crassa DLM- (DE1Xc)
Ae. cylindrica DECc
Ae. geniculata UM (UMo)
Ae. heldreichii
Ae.juvenalis DMU (DEXEUJ)
Ae. kotschyi US (US1)
Ae. ligustica
Ae. longissima S1
Ae. markgrafii
Ae. meyeri
Ae. mutica T
Ae. neglect UM (UXn)
Ae. ovata
Ae. peregrina US (US1)
Ae. persica
Ae. seansu
Ae. searsii S5
Ae. sharonensis Ssh
Ae. speltoides S
Ae. squarrosa (syn. tauschii) D
Ae. strangulata
Ae. triaristata
Ae. triuncialis UCt
Ae. typical
Ae. umbellulata U
Ae. uniaristata N
Ae. variabilis
Ae. ventricosa DVNV

Underlined genomes are modified at the polyploidy level. Those in brackets were deduced
from DNA analysis.


C. History of CIMMYT's Gene Bank

C.1. Maize
The current holdings of CIMMYT's maize germplasm
collection can be traced to samples of landraces
collected and regenerated from 1943 to 1959 by the
Office of Special Studies, a research unit operated
jointly by the Rockefeller Foundation and the Mexican
Ministry of Agriculture. Collections were made
initially to assemble the raw material for breeding
improved maize in Mexico. Later, these were
broadened to include some 2,000 farmer landraces as
an endowment to humanity and to guard against the
day they would be replaced by improved maize. Soon
thereafter, more than 11,000 samples were obtained
throughout the Americas under a project supported by
the U.S. National Academy of Science-National
Research Council. These were stored in regional
germplasm banks in Brazil, Columbia, Mexico, Peru
and the U.S. Regional Plant Introduction Station.

Two research initiatives were started following the
closing of the Office of Special Studies in 1959: the
National Institute of Agricultural Research (INIA)
formed by Mexico, and the Inter-American Maize and
Wheat Programs launched by the Rockefeller
Foundation to extend the accomplishments of the
Office of Special Studies beyond the borders of Mexico.
Under this new arrangement, the maize collections
gathered previously entered the patrimony of INIA.

The Inter-American Maize Program assisted INIA in
regenerating the newly received collections. In doing
so, the program retained an extra set of the renewed
seed, storing it in a refrigerated facility in Chapingo,
Mexico. This material, augmented by more than 600
new entries from collecting missions in the Caribbean,
Mexico, and Central America, formed the inaugural
holdings of the CIMMYT maize germplasm collection.

After CIMMYT was established in 1966, several other
sets of maize collections were added: backup samples
from the Andean and Central American regions held
temporarily at the U.S. National Seed Storage
Laboratory in Fort Collins, Colorado, USA; collections
originally stored in the Brazilian gene bank; collections
from CIMMYT missions in the Andean region in the late
1960s; and part of the collections from Brazil and
Uruguay collected with support from the International
Board of Plant Genetic Resources (IBPGR).









Following the completion of CIMMYT's facilities in El BatAn, Mexico in 1971, including suitable facilities for long-
term seed storage, all samples in the Chapingo gene bank were transferred to CIMMYT headquarters. Dr. Mario
Guti6rrez, head of the CIMMYT maize gene bank from 1976 to 1996, supervised the transfer and initial
organization at El Batan. By 1973, CIMMYT had sent some 470 shipments of nearly 15,000 samples to researchers
in 80 countries. More than 8,000 accessions had been regenerated and basic information recorded on them.

Additional collections in Latin America and parts of Africa, Asia, and Europe were made in 1974 with
sponsorship by the IBPGR, and some 14,500 samples were obtained. After Dr. Guti6rrez left CIMMYT in 1976, a
maize scientist was assigned part-time responsibility for the gene bank. The limited remaining staff regenerated
nearly 1,000 accessions, and met the seed requests to the bank.

In 1984, following criticism regarding CIMMYT's management of the genetic resources under its care, a -15C
cold storage room was built, doubling the life of seed placed there. Each gene bank accession was subsequently
divided, one portion earmarked for long-term storage as a "base collection" in the new facility, and the remainder
was kept in the intermediate storage or "active" chamber. This dual system continues today.

In 1986, Dr. Suketoshi Taba was appointed fulltime curator of the maize germplasm collection. Dr. Garrison
Wilkes was brought in to help assess the condition of the gene bank and to organize the wealth of handwritten
information on the accessions into a computer database. Later the same year, CIMMYT's Board of Trustees
endorsed a proposal that CIMMYT should continue to collect, conserve, document, and evaluate specific parts of
the global collection of maize germplasm. Discussions with IBPGR led to CIMMYT's acceptance of responsibility
for maintaining a base collection of landraces of maize native to the Western Hemisphere.

C.2. Wheat
From its inception in 1966 to 1981, CIMMYT operated a relatively small germplasm cold storage facility for
conserving small amounts of certain wheat genetic materials, especially those used in or resulting from its own
wheat improvement programs. The first actual gene bank of limited capacity became operational in 1981. The
first head of the wheat collection was Ayla Sencer, taking up her position in 1982. In 1989 she was succeeded by
Bent Skovmand, who led the management of the CIMMYT wheat collection until 2003, widely expanding the
number of accessions held in the gene bank. In 2003 Maarten van Ginkel took over the leadership of the wheat
collection, with the specific objective of increasing the utilization of the many collected genetic resources.

C.3. Wellhausen-Anderson Plant Genetic Resources Center
In September 1996, CIMMYT inaugurated the Wellhausen-Anderson Plant Genetic Resources Center, built to replace
the outdated 25-year-old gene bank and seed distribution facility. Funded in part by the Japanese Government, the
state-of-the-art facility was named in honor of two visionaries in the arena of recognizing and applying the power of
crop genetic resources. Edwin J. Wellhausen, as a staff member of the Office of Special Studies in the 1940-50s,
coordinated and participated in the systematic collection and preservation of native Mesoamerican maize
germplasm. He later served as CIMMYT's first director general. Glen Anderson was a talented wheat scientist,
teacher, research administrator, and especially an inspiring leader who helped spark the Green Revolution.




D. International Laws/Agreements that Affect Genetic Resources

There are a number of international and national laws that address issues related to plant genetic resources for
food and agriculture (PGRFA). A detailed description of these can be found in International Law of Relevance to
Plant Genetics Resources: A Practical Review for Scientists and Other Professionals Working with Plant Genetic
Resources (S. Brandon, editor, Issues in Genetic Resources No. 10, March 2004, International Plant Genetic
Resources Institute, Rome, Italy). Treaties and conventions of major relevance to the operations of CIMMYT's
gene bank are outlined briefly below.









* International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA) was adopted by the
FAO Conference in 2001. It came into force in June 2004 following ratification by the 40th country. It is
legally binding for all countries that ratify. Countries that ratify are required to bring national laws and
regulations into conformity with the Treaty. CGIAR Centers, including CIMMYT, will likely sign
agreements with the Treaty's Governing Body in order to adhere to the ITPGRFA. The ITPGRFA covers all
PGRFA and addresses conservation, use, international cooperation, technical assistance and farmers' rights.
It established a multilateral system for select crops. (Details at www.fao.org/ag/cgrfa/itpgr.htm). The
following crops, managed in CIMMYT's gene bank, are included:

Barley Hordeum
Triticale Triticosecale
Wheat Triticum et al., including Agropyron, Elymus and Secale
Maize Zea, excluding Zea perennis, Zea diploperennis and Zea luxurians
Tripsacum Tripsacum luxum

* Convention of Biological Diversity (CBD) is legally binding for all countries that have ratified (168 as of
October 2004). All ratifying countries must adopt appropriate legislation and regulations and/or bring
those existing into harmony with the Convention. It covers all biodiversity and provides general principles
for access and benefit-sharing of materials accessed after the coming into force of the CBD and not covered
by the ITPGRFA (i.e., non-multilateral and non-CGIAR PGRFA). (Details at www.biodiv.org)

* International Plant Protection Convention is a legally binding document for the 113 countries that are
party to the Convention. It addresses phytosanitary issues involving the transfer of plants and animals,
including PGRFA. (Details at www.ippc.int)

* FAO Global Plan of Action was adopted in 1996 by the 4th International Technical Conference on PGRFA
involving 150 countries. It is legally non-binding like the International Undertaking (description follows)
and serves as a framework, guide and catalyst for PGRFA. It addresses all PGRFA and contains specific
references to in situ and ex situ conservation, institutions, and capacity building. It is referenced in the
ITPGRFA. (Details at www.fao.org / ag / AGP / AGPS / GpaEN / gpatoc.htm)

* FAO-CGIAR Agreements were signed in 1994 by the then 11 CGIAR Centers, including CIMMYT, that have
ex situ collections. The agreements apply to the management, availability and transfer of designated
germplasm in the Centers' gene banks. All such "in-trust" accessions are distributed under a common,
agreed Material Transfer Agreement (MTA). These agreements were foreseen as interim pending the
ratification of the ITPGRFA.

* International Undertaking on Plant Genetic Resources (IU) was adopted by the FAO in 1983 and 113
countries agreed to adhere to the IU. All provisions are voluntary because the IU is a non-binding
agreement. The IU covers all PGRFA and addresses the exploration, preservation, evaluation, and
dissemination of PGRFA. The FAO-CGIAR "in trust" agreements refer to the IU. The IU has been
renegotiated resulting in the ITPGRFA and thus has been superceded by this treaty. (Details at
www.fao.org / ag / cgrfa / IU.htm)










II. Germplasm Bank Operations






A. Physical Infrastructure
The Wellhausen-Anderson Genetic Resources Center (GRC) was inaugurated in September 1996. This state-of-
the-art complex houses CIMMYT's operations in maize and wheat international nurseries and germplasm
collections. The gene bank is a two-floor structure constructed using reinforced concrete walls. On the main floor
is a chamber maintained at -3C and 25-30% relative humidity (RH) that contains the "active" maize and wheat
collections. Seed here has an average shelf life of approximately 30 years for maize, and 30-50 years for wheat.

On the lower level is an equivalent chamber maintained at -18C. Similar rows of movable shelving are used
to store the base and black-box collections. Seed stored in this chamber has a shelf life of approximately 60
years for maize and for wheat. Access to the storage chambers is through a multi-locked entry system. Entry
into the hallway leading to the main germplasm bank entrance is through a glass door that is opened via an
electronic key card. Only authorized personnel have such a key card.

Access to the gene bank anti-chamber is through a steel and aluminum door with a numeric coded lock.
Again, only authorized personnel have the code necessary to enter the bank. Inside the anti-chamber are
stairs and a freight elevator leading to the lower floor and storage room. Access into each storage chamber is
via a sliding steel and aluminum, thermal insulated door, again with a numeric coded lock.

Temperature and RH is monitored via remote sensing devices in several locations in both chambers.
Germplasm bank staff monitor these daily for any fluctuations. Alarms are installed to indicate when either
chamber deviates from the set point. A diesel generator provides 24/7 automatic dedicated backup power to
the gene bank lighting, air conditioning, and access locks during power outages.

The GRC complex also houses areas for seed preparation, short-term storage, seed drying, and germination
testing. For the growth of plants for either observation and/or regeneration, the GRC has access to
greenhouses, net-houses, and field space in CIMMYT's El Batan station. Additional field space is available at
other CIMMYT research stations in Mexico: Cd. Obregon (wheat), Toluca (wheat), Aqua Fria (maize) and
TlaltizapAn (maize). Each of these sites provides appropriate climatic conditions for the regeneration of most
maize and wheat accessions held in the gene bank. Certain varieties, especially of maize, require regeneration
outside Mexico and these are done in collaboration with national programs in the appropriate country
(usually close to the point of original collection).




B. New Introductions/Accessions to the Maize and Wheat Collections
Introducing new materials into the gene bank is perhaps the most critical step in bank operations. Following
are the guiding principles for new introductions into the maize and wheat germplasm collections.

B.1. Maize: guiding principles for new introductions
B.1.1. The CIMMYT maize collection holds representative Latin American maize landrace diversity as a
core of maize genetic resources in collaboration with the NARS gene banks.

B.1.2. CIMMYT will continue to cooperate with the national partners in Latin American and in other
regions of the world to collect, regenerate, and preserve landrace diversity.


l10II










II. Germplasm Bank Operations






A. Physical Infrastructure
The Wellhausen-Anderson Genetic Resources Center (GRC) was inaugurated in September 1996. This state-of-
the-art complex houses CIMMYT's operations in maize and wheat international nurseries and germplasm
collections. The gene bank is a two-floor structure constructed using reinforced concrete walls. On the main floor
is a chamber maintained at -3C and 25-30% relative humidity (RH) that contains the "active" maize and wheat
collections. Seed here has an average shelf life of approximately 30 years for maize, and 30-50 years for wheat.

On the lower level is an equivalent chamber maintained at -18C. Similar rows of movable shelving are used
to store the base and black-box collections. Seed stored in this chamber has a shelf life of approximately 60
years for maize and for wheat. Access to the storage chambers is through a multi-locked entry system. Entry
into the hallway leading to the main germplasm bank entrance is through a glass door that is opened via an
electronic key card. Only authorized personnel have such a key card.

Access to the gene bank anti-chamber is through a steel and aluminum door with a numeric coded lock.
Again, only authorized personnel have the code necessary to enter the bank. Inside the anti-chamber are
stairs and a freight elevator leading to the lower floor and storage room. Access into each storage chamber is
via a sliding steel and aluminum, thermal insulated door, again with a numeric coded lock.

Temperature and RH is monitored via remote sensing devices in several locations in both chambers.
Germplasm bank staff monitor these daily for any fluctuations. Alarms are installed to indicate when either
chamber deviates from the set point. A diesel generator provides 24/7 automatic dedicated backup power to
the gene bank lighting, air conditioning, and access locks during power outages.

The GRC complex also houses areas for seed preparation, short-term storage, seed drying, and germination
testing. For the growth of plants for either observation and/or regeneration, the GRC has access to
greenhouses, net-houses, and field space in CIMMYT's El Batan station. Additional field space is available at
other CIMMYT research stations in Mexico: Cd. Obregon (wheat), Toluca (wheat), Aqua Fria (maize) and
TlaltizapAn (maize). Each of these sites provides appropriate climatic conditions for the regeneration of most
maize and wheat accessions held in the gene bank. Certain varieties, especially of maize, require regeneration
outside Mexico and these are done in collaboration with national programs in the appropriate country
(usually close to the point of original collection).




B. New Introductions/Accessions to the Maize and Wheat Collections
Introducing new materials into the gene bank is perhaps the most critical step in bank operations. Following
are the guiding principles for new introductions into the maize and wheat germplasm collections.

B.1. Maize: guiding principles for new introductions
B.1.1. The CIMMYT maize collection holds representative Latin American maize landrace diversity as a
core of maize genetic resources in collaboration with the NARS gene banks.

B.1.2. CIMMYT will continue to cooperate with the national partners in Latin American and in other
regions of the world to collect, regenerate, and preserve landrace diversity.


l10II










II. Germplasm Bank Operations






A. Physical Infrastructure
The Wellhausen-Anderson Genetic Resources Center (GRC) was inaugurated in September 1996. This state-of-
the-art complex houses CIMMYT's operations in maize and wheat international nurseries and germplasm
collections. The gene bank is a two-floor structure constructed using reinforced concrete walls. On the main floor
is a chamber maintained at -3C and 25-30% relative humidity (RH) that contains the "active" maize and wheat
collections. Seed here has an average shelf life of approximately 30 years for maize, and 30-50 years for wheat.

On the lower level is an equivalent chamber maintained at -18C. Similar rows of movable shelving are used
to store the base and black-box collections. Seed stored in this chamber has a shelf life of approximately 60
years for maize and for wheat. Access to the storage chambers is through a multi-locked entry system. Entry
into the hallway leading to the main germplasm bank entrance is through a glass door that is opened via an
electronic key card. Only authorized personnel have such a key card.

Access to the gene bank anti-chamber is through a steel and aluminum door with a numeric coded lock.
Again, only authorized personnel have the code necessary to enter the bank. Inside the anti-chamber are
stairs and a freight elevator leading to the lower floor and storage room. Access into each storage chamber is
via a sliding steel and aluminum, thermal insulated door, again with a numeric coded lock.

Temperature and RH is monitored via remote sensing devices in several locations in both chambers.
Germplasm bank staff monitor these daily for any fluctuations. Alarms are installed to indicate when either
chamber deviates from the set point. A diesel generator provides 24/7 automatic dedicated backup power to
the gene bank lighting, air conditioning, and access locks during power outages.

The GRC complex also houses areas for seed preparation, short-term storage, seed drying, and germination
testing. For the growth of plants for either observation and/or regeneration, the GRC has access to
greenhouses, net-houses, and field space in CIMMYT's El Batan station. Additional field space is available at
other CIMMYT research stations in Mexico: Cd. Obregon (wheat), Toluca (wheat), Aqua Fria (maize) and
TlaltizapAn (maize). Each of these sites provides appropriate climatic conditions for the regeneration of most
maize and wheat accessions held in the gene bank. Certain varieties, especially of maize, require regeneration
outside Mexico and these are done in collaboration with national programs in the appropriate country
(usually close to the point of original collection).




B. New Introductions/Accessions to the Maize and Wheat Collections
Introducing new materials into the gene bank is perhaps the most critical step in bank operations. Following
are the guiding principles for new introductions into the maize and wheat germplasm collections.

B.1. Maize: guiding principles for new introductions
B.1.1. The CIMMYT maize collection holds representative Latin American maize landrace diversity as a
core of maize genetic resources in collaboration with the NARS gene banks.

B.1.2. CIMMYT will continue to cooperate with the national partners in Latin American and in other
regions of the world to collect, regenerate, and preserve landrace diversity.


l10II










B.1.3. Several systematic collection missions for maize germplasm in the Western Hemisphere were
conducted during the past 60 years. CIMMYT will continue to conserve these samples as they represent a
major and valuable part of original maize diversity.

B.1.4. There is need for collection of intra-racial diversity of locally important maize races for conserving
them ex situ and in situ in parts of Mexico, Central America, and the Andean and Amazonic regions of the
South America, and in other continents.

B.1.5. There is a need to identify and conserve diversity in landraces from Africa and Asia because they are
likely to contain unique tropical, subtropical, and highland germplasm adapted to unique climatic and
edaphic conditions.

B.1.6. There is a continuing need to conserve enhanced germplasm, germplasm with useful traits, obsolete
but unique varieties, and lines used in genetic and genomic research.

B.2. Wheat: guiding principles for new introductions
B.2.1. Through the introduction of new wheat accessions, the gene bank works to produce representative
samples of diverse alleles in the three wheat genomes, that are available for long-term storage and
distribution, as feasible.

B.2.2. Undertake collection expeditions where previously no collections have taken place or where additional
genetic diversity of interest is expected to reside based on GIS or other information regarding prevailing
climate and soil conditions.

B.2.3. Acquire critical germplasm, such as cultivars from around the world released by breeders in the 20th
century that are now obsolete.

B.2.4. Maintain collections of selected germplasm representative of all significant germplasm pools.

B.2.5. The type of wheat genotypes included in the wheat collection include:

Wheat's diploid and tetraploid undomesticated ancestor species
Primitive domesticated wheats
Landraces
Commercial wheat cultivars from around the world
Advanced lines bred by CIMMYT breeders over the course of its history
Genetic stocks (e.g., cytogenetic stocks, deletions, point mutations, -mono- and polysomic series,
translocations, mapping populations)
Miscellaneous stocks of rye and other related grasses
DNA of selected entries
Barley germplasm is stored only as a working collection for the joint ICARDA-CIMMYT Barley Program.


B.3. Introduction of new materials
B.3.1. Sample registration
New accessions are introduced into the gene bank with passport documentation after clearing quarantine
regulations of Mexico as necessary. Upon receipt, a gene bank identification or accession ID (e.g., CIMMYTMA-
000001 for maize, or codes starting with CWI/BW/DW followed by sequential numbers for wheat species and
landraces, bread wheat advanced lines, or durum wheat advanced lines, respectively) is assigned to the new
introductions/accessions. Passport data are registered into the database for each new accession. Throughout its
existence in the gene bank and when shared with others the accession ID links the accession to the gene bank's
central database. The ID number is also associated with passport, characterization and/or evaluation data,
which can be stored, searched, and retrieved.


=a11=










r3OEJR OLNETION


INPCINREGISTER


-gZi~~


/%^IO^n
[CONTAINER


\ CRITErARIA

^_DATA OUTPUT

SEED
OUTPUT
\UTPUT


Figure 1. Gene bank operation (wheat). Small samples of seed are received and enter the germplasm bank (top of the flowchart).
It is then checked for seed health by the Seed Inspection & Distribution Unit (SIDU), its passport data is registered in the database and it is
assigned an accession ID. The seed is then multiplied to have sufficient seed to store and satisfy outside requests. The seed is dried to a low
moisture level to increase its longevity, and five sub-samples are assigned 3D storage IDs that record the physical location of the seed in
the gene bank. The five sub-samples are stored (i) in the active collection to satisfy client requests, (ii) in the very long-term storage area
of the base collection; (iii) maintained for later germination tests, (iv) shipped as back-up seed to the National Center for Genetic Resources
Preservation (NCGRP) in Fort Collins, Colorado, USA, and (v) shipped as back-up seed to ICARDA in Syria. After seed requests arrive and
are documented, desired seed is taken from the active collection and processed for shipment. Finally the seed is sent to the requesting
collaborator through the International Wheat Information Network (IWIN). Evaluation for specific traits and pre-breeding activities enhance
the usefulness of the products that we make available to breeders worldwide. Regeneration takes place as seed quantity or germination
percentage drop below set limits. At all levels data is generated and stored in a central database.


a12


-a -REBREEIN


REGENERATIO









B.3.2. Seed health procedures
All new maize and wheat germplasm (landrace collections, breeder lines, breeder populations, gene pools,
genetic materials, and related species) are sent to the CIMMYT Seed Inspection and Distribution Unit (SIDU),
where they are inspected following Mexican quarantine regulations in the seed laboratory and greenhouse.
The SIDU works under its own operational procedures (Mezzalama et al., 2001).

B.3.3. Seed cleaning and seed drying
After SIDU's inspection and clearance, seed is cleaned and dried in a drying room at 100C and 25% RH to
a seed moisture of 6-8% for maize
a seed moisture of 5-7% for wheat
in equilibrium with the drying conditions. This normally takes 6-8 weeks.

B.3.4. Seed moisture content, seed viability, and reference seed samples
After seed drying, seed moisture content is measured to determine if it has reached the required reduced-
moisture level. Subsequently, initial seed viability is tested. Initial seed germination must be more than 90%.
Information on the moisture content, germination ability and seed weight, are registered in the central
database. The amount of the seed available is measured before seed packaging and storage. For potential
future identification purposes, a sample of 50-200 seeds from the original sample is packaged for storage as
the reference sample. Landrace collections often include segregating seed textures, colors, and shapes. The
reference samples are useful for rechecking the accession identity after regeneration. These reference samples
are maintained in the base collection.

B.3.5. Base collection (long-term): seed packaging and seed storage
Seed is packaged in a laminated aluminum foil packet that can contain about
1 kg (1,000-2,500 seeds) normal maize seeds
100 grams (about 3,000) wheat seeds.
The packet for maize is 7.0-7.5 cm (depth) x 10 cm (width) x 15-16 cm (height). The packet for wheat is 6 cm
(depth) x 26.5 cm (height) x 8.9 cm (width). The packages are hermetically sealed.
Two packets are prepared for the base collection for maize at regeneration
One packet is prepared for the base collection of wheat. For wheat, the laminated aluminum foil
packets are packaged into boxes, 75 packets to a box. Boxes are coded and information, including where
the boxes are shelved within the storage facility, is entered into the central data base.

B.3.6. Active collection: seed packaging and storage
For the active maize collection (where seed is obtained to respond to outside requests), one-gallon
plastic airtight containers holding 2-3 kg (5,000-10,000 seeds) are used for storage.
For the active wheat collection, laminated foil packets holding 250 grams (about 7,000 seeds) are used.
The foil packets are packaged 40 packets to a box. Boxes are coded and information, including where
the boxes are shelved within the storage facility, is stored in the central data base.

All seed processing operations entail careful handling of the seed packets and containers. Seed weight (1000
test weight) and initial seed amount stored in the active and base collections are recorded. During seed
processing, seed characteristics are checked against the passport data to insure the correct accession identity
by seed texture, color, and shape. No fungicide and insecticides are used for seed storage, except in certain
cases where the incoming seeds underwent seed treatment as required by quarantine regulations.

B.3.7 Introduction nursery and quarantine inspection
Following the application of proper seed health procedures, new maize introductions are planted in the
introduction nursery at CIMMYT's Tlaltizapan (tropical and subtropical maize materials) or El Batan
(highland and temperate maize materials) stations. In the case of wheat, new introductions are planted in a
screenhouse at El Batan. CIMMYT seed health specialists and Mexican quarantine authorities inspect
incidence of diseases and other traits during the growing period and harvest in the nursery. Careful hand-
pollination is conducted for maize to increase the introductions as required. Wheats will naturally self-
pollinate, and little, if any, pollen movement occurs within a screenhouse.


a13









Further increase or regeneration, if needed, is performed by planting accessions in regeneration nurseries to
obtain enough quality seeds for storage in the gene bank.

For maize, these procedures are conducted at CIMMYT's Tlaltizapan (tropical and subtropical maize
materials) or El Batan (highland and temperate maize materials) stations.
For spring wheat accessions, these procedures are conducted in Mexicali, an essentially disease-free
location in the northwest Mexico.
For winter wheat accessions, these procedures are conducted at the CIMMYT highland Toluca station
(for more details, see section D, "Regeneration of Introductions/ Accessions," p. 15).

The plot size for the introductions in the introduction nursery depends on the amount of seed available and
the required quarantine inspection. Any risk factors that exist in the introductions-such as presence of
diseased seed or a transgene-would require pre-screening for characterization or purification, or elimination
before and after planting in the nursery. Introduction nursery blocks are isolated from the other nursery
blocks in the stations.

B.3.8 Reintroduction of the seed accessions into the gene bank after regeneration and seed increase
The accessions regenerated at CIMMYT stations and by the cooperators outside CIMMYT such as the case for
maize in Andean regions of South America go through the plant health unit procedures for reintroduction of
the seed accessions into the gene bank. Stringent inspection is applied to the germplasm samples coming from
risk prone regions) or site(s) in terms of transgenes and epidemic diseases. The same reintroduction
procedure is applied to the seed lots increased in the introduction nurseries.

Characterization data is taken both in the introduction and regeneration nurseries. Field books are printed
separately for the new introductions and the accession regeneration. The seed health clearance of all incoming
seed accessions from regeneration and seed increase are required each time and recorded in the gene bank
database system. The SIDU also regularly monitors the germplasm bank working areas for the presence of
disease spores. Seed health inspection at entry point to the gene bank reduces the need of seed health
inspection when they are requested by the users.




C. Seed Viability and Germination Tests

The CIMMYT gene bank maintains seed viability as high as possible during seed storage. The initial
germination test of seed lots of new introductions or seed increased in the introduction and regeneration
nurseries is conducted after the seed is dried to the optimal moisture content (6-8% for maize; 5-7% for wheat).

The initial germination test of seed accessions must exceed 90% germination to be stored in the gene bank. All
new introductions stored in the gene bank will become new storage units, with the same bank identification
number that was given during sample registration. Regeneration may be repeated two to three times to
produce sufficient quality seed.

In the course of seed preservation for the active collection, if seed viability of the accessions drops below 85%,
or the number of seeds falls below 1,500, the accession is regenerated or multiplied. The first monitoring of
seed viability is conducted after ten years of storage in the active collection; then, after every five years as
recommended by the standard germplasm bank operation guidelines (FAO/IPGRI 1994).

CIMMYT follows the ISTA rule to count the seeds that have normal and abnormal germination after four days
and seven days to determine percent of germination.


11M141









For maize, absorbent paper is used for the germination tests.
For teosinte, absorbent paper is used for the germination tests. The seeds can be pretreated to break
dormancy with 20% hydrogen peroxide (H202) solution for 24 hours before germination. Some
teosinte accessions can germinate without seed treatment.
For Tripsacum, the embryo is separated from rachis and germinated in asceptic conditions using N6
media without hormones.
For wheat, petri dishes lined with sterile filter paper are used for germination tests.

The rolled wet paper with (maize) seeds, or petri dishes with (wheat) seeds, is/are placed inside a germinator
at 25 C and 100% RH with a 12/12 hours dark/light regime. Normally, two sets of 50 seeds each are tested for
monitoring seed viability of each accession. If the variability between the two replications is high, another
germination test is conducted with either 50 or 100 seeds.




D. Regeneration of Introductions/Accessions
Multiplication and regeneration are two of the most important functions of a gene bank because the
long-term viability of seed is very much dependent on the quality of the seed being placed in storage. It is
ultimately the objective of the gene bank to provide the allele that was successfully sampled in a distant
farmer's field during a collection trip or that is present in a wheat relative, when a small seed sample is
provided to the person requesting such genetic diversity. Rather than globally common alleles, interest is
in those alleles that are regionally common due to local adaptation conditions (e.g., abiotic or biotic
stresses, consumer end-use preference) or that are globally rare (e.g., alleles providing stability in low
numbers to a dynamic system). Therefore, during this process of seed regeneration care must be taken to
avoid genetic drift resulting in allele loss, as well as mechanical mixtures and other handling errors. The
dimensions (i.e., number of seeds and measures of genetic diversity) of the original sample, of the sub-
sample to be multiplied, of the newly multiplied sample to be stored for humanity, and of the sample sent
out addressing future requests must be carefully considered (Wang et al., 2004). The chance of the loss of
rare alleles can be calculated through simulation routines and provide guidelines as to the preferred
multiplication procedures and seed numbers required.

It is clear that any round of seed multiplication carries with it a chance of losing rare alleles. It is therefore
paramount that seed storage conditions are such that seed needs be multiplied as few times as possible. This
is best obtained by lowering the seed moisture content to the recommended values and maintaining the seed
at a low temperature, where respiration is reduced dramatically, but further reduction in temperature adds
little to raising the odds for proper conservation while costs increase greatly.

D.1. Maize regeneration
Latin American maize landraces are adapted to the tropical, subtropical, and highland growing conditions.
Regeneration of maize germplasm accessions should take place where they can adapt and reproduce
themselves in a cost effective manner, while maintaining the original genetic integrity of the populations.
Artificially controlled pollination and proper seed management for ex situ conservation is the key to proper
gene bank operations. Following are the protocols for planting, pollinating and harvesting accessions of
maize at CIMMYT.

Tropical and subtropical maize accessions are regenerated at CIMMYT's Tlaltizapan experiment
station, Morelos, Mexico (940 masl). The maize growing seasons start in October (cycle A) and April
(cycle B). Highland maize accessions are regenerated at CIMMYT's El Batan station (2,300 masl).
Andean highland and some of the Central American highland accessions are not well adapted to the
El Batan highland station. They are regenerated in collaboration with the national gene banks,
following the same regeneration protocol followed by CIMMYT.


Ia151










The seed for the accession are prepared from the base collection. The accessions are grouped by
maturity to facilitate pollination.
For regeneration, seed packets containing 512 seeds each are prepared and transported to the
appropriate field site. They are planted in the regeneration nursery (1-2 ha in block size) that is
isolated from other nursery blocks in the station. Each packet is sown in 16, rows each 5 meters long.
Two seeds are planted in each of 16 hills in 5 meter rows and later thinned to establish 256 plants per
plot (60 m2).
Field plot management follows the normal maize growing practice of the station.
Chain crosses (most often), paired crosses (as required) or selling (inbreds) are used for the controlled
pollination in all regenerations. Artificially controlled pollination is used to avoid contamination by
other pollen sources at anthesis and silking. The ear shoot of each plant is covered with a shoot bag
(glassine) before the silks emerge and a tassel bag (pollination bag) is placed on the male flower
(tassel) to collect pollen the day before pollination.
CIMMYT's maize pathologist inspects the plant health in the regeneration blocks. Clean ears are
harvested to insure seed quality for seed health inspection and seed longevity. Harvested ears are
inspected individually and diseased kernels or undesirable kernels such as those not well filled or
broken are removed on the cob before and after shelling. Ear rots often reduce the number of quality
ears at harvest.
After harvest, individual ears are shelled into a paper envelope, cleaned, and inspected for accession
identification. For the base collection, two sets of a balanced seed bulks of 50 seeds (about 1.5-2 kg) each
are prepared. For the active collection, another balanced seed bulk is prepared containing about 100
seeds (3 kg). One seed bulk of the base collection is used for safety duplicate storage at NCGRP, Fort
Collins, Colorado, USA.
Every cycle, the regenerated seed samples of the accessions are sent to the seed health unit (70 seeds
per accession) prior to introduction of the accessions into the gene bank.
Regeneration of the accessions is repeated in order to obtain enough sample size and quality ears.
The seeds of initial and repeated regeneration plantings are combined to represent the regeneration of
the accession.
The bank identification numbers and the field plot numbers of the accessions under regeneration are
placed on the seed envelopes, cloth bags, and the field labels to make sure their identity.

The standard practices for maintenance of genetic integrity of germplasm collection accessions involve
proper sample size, a system of artificial pollination, and accession identification.

D.1.1. Proper sample size
A proper sample size must be employed in order to avoid loss of genetic diversity from generation to
generation due to population bottlenecks. An optimum sample size for regenerating maize landrace
accessions (panmictic populations) is determined by the frequencies of the rare alleles present in the
accession. Based on statistical data, CIMMYT has determined that the proper sample size is based on
producing 100 or more ears for regenerating landrace accessions (Crossa, 1989; Crossa et al., 1994; Wang et.
al., 2004).

D.1.2. Artificial pollination
Artificial pollination control is made either by plant to plant crosses (dioecious mode) or by chain crosses
monoeciouss mode) within the accession. The appropriate mating system is used for maintaining effective
population size. Plant to plant crosses require twice as much land as chain crosses to produce the same
number of ears. Usually, chain crosses are used to regenerate a large number of accessions. Inbred lines are
selfed or sib-mated. Throughout the regeneration cycle, it is important to maintain an equal effective
population size to avoid genetic drift, inbreeding, and associated loss of alleles. Contamination by other
germplasm or alien pollen sources must also be avoided.


M=1










D.1.3. Accession identification
The regeneration of an accession not only provides the ex situ gene bank manager with quality seeds for storage
and distribution, but also with an opportunity to ensure the accession identity. Seed color and texture, ear and
grain types, and maturity and race classification are rechecked against the original records of the accession in the
passport data, which are printed in the regeneration field book.

The regeneration field book is used to register data on the number of plants germinated and established, the
number of plants pollinated and harvested, agro-morphological plant and ear traits, the amount of seeds
produced for the active and base collection, date of seed storage, initial germination percentage, seed moisture
percent at seed storage, previous regeneration site and plot number, and date of the previous regeneration. All
data are kept in the regeneration dataset in the bank database system.

D.2. Teosinte regeneration
For regenerating or seed-increase of teosinte accessions, 100-150 seeds of each accession are germinated in an
environment chamber and germinating seeds are planted in plastic pots to flower during the off-season of maize,
between cycles A and B at the Tlaltizapan station. A pot contains 6-10 plants. The accessions are grown in the
plastic pots and are located 200 meters or more apart from maize or other plantings, along the edge of the station.
At maturity, the seeds are collected from the spikes and non-fertilized seeds are removed from the seed lots before
drying. The seeds are dried at 10C and 25% RH for 1 month before processing for the active and base collections.

D.3. Tripsacum regeneration
A field germplasm bank at the Tlaltizapan station maintains Tripsacum clones collected in Mexico, Central and
South America, and the USA (Berthaud et al. 1997). The blocks of the field germplasm bank are separated from
the rest of the blocks in the station. Most of the accessions are represented by two clones. For collecting seeds,
sets of several spikes are bagged in each clone and the seed lots collected are cleaned of unfertilized seeds for
conservation. It is often difficult to obtain enough seeds because each spike will have only a few seeds and also
because the seed samples may contain hybrid seeds. Clonal propagation is an alternative means of distribution.
Some Tripsacum species do not flower, although the majority do during the summer months. In the field
germplasm bank, maize-Tripsacum hybrids do not occur.

D.4. Wheat regeneration
CIMMYT multiplies wheat seed in a disease free location or within a semi-contained screenhouse, to obtain
healthy seed prior to cooled storage. The latter facility expedites the production of quality seed for medium-
and long-term storage. Depending on whether the accession is a spring (non-vernalization requiring) or
winter (vernalization requiring) habit genotype, or a domesticated or wild relative they are regenerated in
different locations.

Mexicali is located in the northeast of Mexico, where Karnal bunt (KB), a quarantinable disease does not
occur. Here, domesticated spring wheats are regenerated. During flowering time, when in theory KB
spores could infect the florets, fungicides are applied at intervals to cover all accessions, even if they
differ in flowering date. About 10-15,000 entries are regenerated here annually.
Toluca is located in the Mexican central highlands at 2,640 masl, and in winter experiences at least 8 weeks of
temperatures below 4C at night. Generally these conditions are sufficient to vernalize most facultative and
winter wheats. Winter wheats are multiplied here, if their day length requirement is not too long. They are
also treated with fungicides as described above. Several hundred to several thousand entries are regenerated
here annually.
Screenhouses at El Batan, CIMMYT, HQ. This location is also located in the Mexican central highlands,
though 400 meters lower than Toluca. The screenhouses are equipped with special high-intensity
lighting, to allow the long day-length required by day-length sensitive wheats to be satisfied. Several
hundred entries are regenerated here annually.


=a17l









An important consideration in seed multiplication and regeneration is the amount of seed to be planted. The
number of seeds planted or the actual number of spikes or plants harvested depends on two factors:
homogeneity or heterogeneity of the accessions, and size of the seed sample originally received.

Initially, upon receipt of a seed sample from outside the gene bank, 25-50 seeds are planted. If an accession is
visually judged homogeneous, one basic unit of seed is produced for storage (split between the base and
active collection). Given the self-pollinating nature of wheat, many advanced lines and commercial cultivars
show little, if any, visual heterogeneity. However, if heterogeneity is noted (e.g., often the case with landraces),
the original sample is stored as is, but during the initial multiplication phase separate sub-samples (i.e.,
individual spikes from distinct plants) are taken to represent the diversity observed. In the database such sub-
samples are handled separately to avoid remixing, but noted as deriving from the original sample received,
linked through their original accession ID.

Presently, the number of sub-samples taken from heterogeneous introductions may vary from 2 to 100,
depending on the visual diversity noted. Landraces may, upon planting under conditions outside their area of
origin, display a wide array of diversity. If there are doubts as to the number of sub-samples to produce, we
prefer to err on the high side to ensure maintenance of all potential useful diversity.

Once major and minor wheat cultivars and advanced lines of interest from around the world are stored in the
gene bank, no active search is made to re-acquire seed of the same genotypes from outside for storage.
However, if cultivars from one country are released in another country under the same, similar, or totally
different name (e.g., Mexican cultivar Pavon 76 released in Ethiopia under the name Pavon; Indian cultivar
HD2172 released as Debeira in the Sudan) seed of both releases will be sought and stored. The reason is until
precise molecular studies can be conducted, one cannot be sure whether such accessions are totally identical.
There may be various reasons why in fact they are (somewhat) different, which include, labeling error,
planting error, outcrossing, genetic drift, and mutations. Such seemingly identical accessions are stored under
distinct introduction IDs, so that distinct passport data related to their physical origin is maintained by the
unique introduction ID. The total number of such potential 'duplicates' held in the CIMMYT germplasm bank
is probably less than 2,000 accessions.



E. Evaluation of Maize and Wheat Accessions

Objectives of phenotypic evaluation are to document the extent of diversity of phenotypic traits and to choose
representative subsets (core subsets) of the stratified groups in the maize and wheat landrace collections.

For phenotypic evaluation of landraces, we have taken the approach of stratifying them by race groups and
geographic origins. However, in the future we plan to introduce GIS-based criteria to better stratify our
collection. This would allow the linkage of accession data to environmental and edaphic data at the site of the
original collection.

The traits or characteristics that need to be evaluated are demand-driven and decided in discussions with the
breeders, including those at CIMMYT HQ and regional offices, as well as breeders from partner organizations.
Evaluation, therefore, is carried out for traits for which breeding programs lack variability or lack durable
forms of diversity. In the case of wheat, the following traits have been identified as high priority:

yield potential through expanded diversity in yield components, and physiological processes;
resistance to diseases and pests, of a more durable nature;
tolerance to such abiotic stresses as drought, heat, cold, acid soils, salinity, waterlogging, particulate
and ozone air pollution, micro-nutrient excess or deficiency;
improved and diversified quality (including micronutrients) for a wider range of end-use products
more representative of our clientele, including future alternative uses, such as bio-degradable products
and bio-pharmaceuticals;


M181










adaptation to more sustainable production practices, such as conservation tillage (e.g., zero/
minimum tillage, plant residue retention); and
genetic diversity to study underlying processes in physiological pathways.

Evaluation can be carried out by gene bank personnel, by fellow CIMMYT scientists expert in their
disciplines either within or outside Mexico, or by colleagues outside of CIMMYT working with national
wheat improvement programs in public or private settings either in developing or developed countries. An
example of a combination of joint collaborators is the request by bread wheat breeders to evaluate gene bank
accessions for sources of resistance to the powdery mildew (Erysiphe graminis). With powdery mildew not
endemic in Mexico in our research fields, we turned to colleagues in China, France, South Africa, the UK and
Uruguay, to help us evaluate and acquire new resistances.

Ex situ evaluation is conducted at CIMMYT experiment stations and in situ evaluation is done in
collaboration with cooperators at sites nearest to where the germplasm accessions were collected.

For maize, evaluation is conducted as two replications of two 5 meters rows per plot for each entry, with 32
plants arranged in alpha lattice design. The trial is evaluated at one or several locations.

For wheat, plot size and experimental design depend on whether disease resistance traits are measured,
which require only small plots, or abiotic stresses, such as drought and heat response, which require large
plots with replications, properly managed for the respective stress.

Morph-agronomic data include

For maize: plant height, ear height, days to silking, days to male flowering, leaf senescence, root and
shoot lodgings, ear length, ear diameter, ears per plant, ear rot%, ears per plant, ear quality rating,
kernel width, kernel depth, kernel row number, grain moisture % at harvest, grain shelling percent,
grain yield, and agronomic rating and other observations such as leaf diseases, insect damage, and
adaptation to the environment are taken in the trial.
For wheat: growth habit, plant height, heading date, flowering date, maturity date, spike length,
spikelets / spike, florets/spikelet, awnlessness, peduncle length, stem thickness, leaf thickness, leaf
rolling, pubescence, agronomic score, tillers per m2, grain yield per per m2, thousand kernel weight,
grain color and appearance, disease ratings, etc.

In maize, a multivariate cluster analysis is performed using the agro-morphological traits, except grain yield,
ear quality rating, ear rot percent, and root and stalk lodgings. Core subsets (20% of the trial entries) are
chosen in each accession cluster using the selection index constructed with seed moisture percent, root and
stalk lodging, and yield (Taba et al. 2003).

In wheat, analyses including GIS information on the original collection sites are carried out that may allow
the identification of those geographic locations that have a higher frequency of useful germplasm for the trait
being studied. As more information is acquired, analyses similar to those carried out for maize can be
conducted to determine core subsets.

Based on preliminary data, two core wheat subsets have been formed in an attempt to capture the diversity
held in thousands of lines into sets of just a few hundred accessions. It is only through such reductions that
one can hope to encourage colleagues around the world to study these sets for traits of relevance to them.
The two core sub-sets are:

Species core subset: 150 accessions, representing 10 distinct sources and combinations of genomes A,
B, and D.
Landraces core subset: 500 landraces from 53 countries, representing putative genetic diversity based
on preliminary origin and geographic (GIS) considerations.


M19









As these two core subsets are studied more widely, especially in regard to their molecular and GIS structure,
we will be able to return to the complete collection for further sub-sampling of clusters either on a genetic or
GIS basis, and to home in on diversity of the greatest promise. While some may claim that developing
imperfect core subsets at this stage is premature, it allows a more focused initial search towards the
development of subsequent improved subsets based on more rigorous data.




F. Shipments

Fl. Maize
The designated germplasm accessions (all maize landrace accessions, teosinte and Tripsacum in Annex-1 in
ITPGRFA, and obsolete varieties and breeding populations) in the in-trust collection under CIMMYT-FAO
agreement (1994) are distributed upon request to all bona-fide users with the interim material transfer
agreement (MTA) pursuant to the International Treaty for Plant Genetic Resources for Food and Agriculture
(ITPGRFA). The germplasm accessions from CIMMYT research products are distributed with the MTA for
non-designated germplasm to all bona-fide users.

Standard shipments for maize are 50-100 seeds; for teosinte 15-20 seeds; and for Tripsacum, 5-15 seeds.
When the bank manager receives the seed requests, he/she will respond to the requester if the seed
accessions are available, or suggest the best suitable seed accessions in the collection and relevant MTA
to be used.
The list of the seed accessions is prepared with the accession and seed identification data: ID number,
race name or common name, seed quantity and origin and plot number, designated or non-designated,
and observation.
The Seed Inspection and Distribution Unit (SIDU) receives the seed packages, seed list, and the formal
seed request from the gene bank and examines the health status of the seed. If required, the standard
seed health procedure is applied to the sample accessions before shipment. All seed shipments of gene
bank accessions are accompanied by the necessary documentation, as required by the recipients (import
permit, phytosanitary certificate, MTA, list of the accessions with key identifiers of the accession and
seed origin, etc).
The seed samples are, for the most part, prepared from the active collection and have the corresponding
bank accession number and a serial number labeled on the seed envelope. The seed samples can be
prepared from the base collection when the requested accessions are only preserved there and there is
sufficient seed stock.
Accessions under regeneration may not be immediately available, and requests may have to wait until
the accessions have been reintroduced.


F.2. Wheat
Most seed requests arrive at the gene bank through email, with a decreasing proportion by postal mail. Plans for
the future call for a fully searchable website with all relevant data posted for the wheat germplasm collection. The
user will be informed within 24-hours of the receipt of the request about how the request will be processed,
including a projected time-line leading to final shipment. The aim is for nearly all requests to be honored, with a
seed shipment arriving in the country of designation one month prior to the upcoming planting cycle. In some
cases, time will be too short to achieve this aim, but seed will be shipped as soon as feasible. If the seed amount
requested is larger than average, an internal round of seed multiplication will be carried out, which will delay the
procedure by about seven months for spring-habit genotypes and 12 months for winter-habit genotypes. If the
request is not for seed but rather for information about DNA samples, then the turn-around time can be reduced
to a matter of days or weeks.


=M20









Present and future seed requests can be divided into two categories:


Genotype-specific seed requests: These requests indicate the specific cultivar name or cross
description. Such requests can be readily fulfilled, seed availability permitting. Further automation of
the process is foreseen for the future.
Information-specific seed request: These requests indicate the traits or origins of the genotypes
requested (e.g., drought tolerant germplasm; all spring wheat accessions from Afghanistan). Here the
gene bank manager will need to conduct an internal search based on the data available relevant to the
information provided. Subsequent correspondence with the requester may be needed to narrow down
or broaden the accessions proposed for final shipment. As data is increasingly posted on the CIMMYT
website, users should be able to search for genotype data on accessions that most closely resemble
those being sought.

Generally, the more specific a request is, either detailing the genotype or the trait(s) sought, the quicker
the response.

Once the identity of the genotype to be retrieved is determined based on the seed request, a small amount of
the seed (i.e., 50-100 seeds) is obtained from the active collection. When this occurs, the database system will
register the reduction in seed stock. In special cases, such as segregating populations or with landraces that
are expected to be highly heterogeneous, larger seed amounts can be requested and sent, seed availability
permitting. However, an intervening round of seed multiplication may be needed.

The seed is treated with a fungicidal/ insecticidal mixture just prior to shipment in order to strictly adhere to
official regulations of national governments regarding seed imports of recipient cooperators. The seed held in
the gene bank is, however, already guaranteed free of disease. During multiplication, fungicides are applied
and the seed is subsequently checked by the SIDU for any form of infection or contamination, prior to it being
stored in the germplasm collection. The SIDU also regularly monitors the gene bank working areas for the
presence of disease spores. All national regulations from cooperating countries are held by CIMMYT in
electronic or hard copy form, and are consulted prior to seed shipment. Particular efforts are made to remain
abreast of new developments in this regard with our cooperating countries.

We encourage cooperators and recipients of seed from our gene bank to share relevant data that may be
collected on it in the future, plus any information on its use, such as the introgression of traits into new
cultivars through breeding that are later made available to farmers.




G. Back-up collections

G.1. Maize
Historically, duplicate samples of maize landrace collections of NAS-NRC in Latin America during the 1940s-
1950s were sent to NSSL, now USDA's National Center for Genetic Resources Preservation (NCGRP) at Fort
Collins, Colorado, USA. Since the mid-1960s, these original samples have been regenerated at CIMMYT and
have become the core of the CIMMYT maize germplasm collection. Most of the samples have now been
duplicated at NCGRP, as recommended by the ex situ conservation network of FAO.

CIMMYT maintains a safety duplicate arrangement (MOU) with NCGRP in a cooperative manner to back-up
its maize germplasm collection. The NCGRP conserves duplicate samples of 82% of the CIMMYT maize
collection (24,450 accessions) at -20C, under long-term seed storage, using CIMMYT gene bank identification
numbers. Upon regeneration of accessions, CIMMYT sends the NCGRP 1-2 kg seed samples to serve as a
back-up. None of the seeds are distributed by NCGRP.


11211 1









CIMMYT also coordinates the maize germplasm conservation network for Latin American national gene banks.
The network project has regenerated about 10,000 accessions and duplicated them at CIMMYT and NCGRP. The
cooperative national gene banks, meanwhile, conserve their own national accessions.

G.2. Wheat
CIMMYT has agreements with NCGRP in Fort Collins, Colorado, USA, and ICARDA in Syria to send these
two parties black-box, back-up seed shipments of CIMMYT wheat and wheat-related accessions held in the
CIMMYT gene bank. Likewise CIMMYT holds a black-box shipment from ICARDA. The rationale is that
materials are thus duplicated in several sites around the world, and in case an environmental disaster or other
circumstances cause accessions to be lost or destroyed, they can be replenished from the back-up location.
The system is based on so-called black-box collections, meaning that the recipient should not open the boxes
or seed packages, but only accept responsibility to store them well in their long-term base storage area. Lists
of the accessions are provided to the recipients. The recipient is prohibited from fulfilling any seed requests
from the black-box accessions, since they are not officially part of their collection, but only kept there for
security reasons. Related seed requests should be channeled to the sender of the black-box shipment.




H. Data Management

H.1. Maize
The datasets of passport, regeneration (characterization), evaluation (core subsets), seed monitoring (seed
amounts, germination, storage address), and seed shipment are incorporated into the current maize gene
bank information database system (MZBANK). A new CIMMYT gene bank database system is under
development.

H.2. Wheat
The management process of the data held by the wheat gene bank, as well as other information residing with
outside cooperators, is currently undergoing review and reorganization. This is primarily driven by the need
to provide internal and external web-service access to the accessions held in the bank, based on information
associated with it through the unique accession ID coding.

Presently, the Wheat Germplasm Bank System (WGBS) is being used for data management. This is a
component of the IWIS software system that electronically manages data (i.e., passport, characterization,
evaluation, and logistical information) in the germplasm bank collection. WGBS can also generate field books
and data reports. This system will soon be upgraded, or integrated with another database management
system, or CIMMYT may choose to develop wholly new software to carry out the task.

The future system will address the following five processing areas within gene bank operations that
generate data:

Introduction of new accessions, registration of related passport data, assignment of ACCID and
storage location ID;
Monitoring and updating storage dates, seed viability, and seed amounts;
Storage of characterization and evaluation data, including germination tests;
Web-enabled searches by users, generation of associated seed request and entry lists, seed shipment
processing; and
Regeneration information as needed.


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I. References


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