Open Access

Development of a core collection of Triticum and Aegilops species for improvement of wheat for activity against chronic diseases

  • Meenakshi Santra1,
  • Shawna B Matthews1 and
  • Henry J Thompson1Email author
Agriculture & Food Security20132:4

DOI: 10.1186/2048-7010-2-4

Received: 26 September 2012

Accepted: 29 January 2013

Published: 15 February 2013

Abstract

Background

The objective of this study was to develop a core collection of Triticum and Aegilops species as a resource for the identification and characterization of wheat lines with preventive activity against chronic diseases. Given that cancer is the leading cause of mortality in the world and shares risk factors with obesity, type-2 diabetes, and cardiovascular disease, and given that wheat has been reported to protect against these diseases, the core collection was developed based on cancer prevalence.

Methods

The Germplasm Resources Information Network (GRIN) database was used to identify Triticum and Aegilops species grown in regions of the world that vary in cancer prevalence based on the International Agency for Cancer Research GLOBOCAN world map of cancer statistics (2008). Cancer incidence data drove variety selection with secondary consideration of ploidy, center of origin, and climate.

Results

Analysis indicated that the geographic regions from which wheat is considered to have originated have a lower incidence of cancer than other geographic regions (P <0.01), so wheat lines from countries that comprise the ‘Fertile Crescent’ were highly represented in the core collection. A total of 188 lines were selected from 62,571 accessions maintained by GRIN. The accessions identified comprised two genera and 14 taxa of 10 species within 19 groups from 82 countries. The core collection is comprised of 153 spring, 25 winter, and five facultative selections of wheat.

Conclusions

A diverse core collection of wheat germplasm has been established from a range of regions worldwide. This core collection will be used to identify wheat lines with activity against chronic diseases using anticancer activity as a screening tool.

Keywords

Aegilops Anticancer activity Cancer Core collection Triticum Wheat germplasm

Background

The consumption of whole grains has long been associated with a healthy lifestyle and chronic disease prevention; in particular, multiple studies have correlated whole-wheat consumption with protection against chronic diseases including cardiovascular disease, stroke, type 2 diabetes, and cancer at multiple sites [18]. However, these studies have failed to discriminate between the type of wheat that is consumed and the chronic disease protective effect observed. Specifically, the USDA has germplasm from 62,571 distinct wheat varieties; given the well-described differences in agronomic traits as a result of genetic polymorphisms within wheat species, as well as the recently characterized metabolite differences between and within wheat species and subspecies [9], further investigation of the chronic disease preventive capacity of individual wheat varieties is required.

In this paper, we propose that a neglected opportunity in the field of diet and chronic disease prevention is the use of staple food crops with defined bioactivity for daily consumption [10]. The rationale underlying this approach recognizes that societies have chosen their staple food crops, which are affordable and generally available to all individuals across socioeconomic strata, and that societies willingly consume these staples in large quantities on a daily basis. These consumption patterns thus provide a stable flow of health beneficial phytochemicals in much the same way that an oral drug is taken to maintain plasma concentrations of the active ingredient in a beneficial range [11]. Further research on bioactivity of specific varieties of these staple food crops is critical, given that major chronic diseases, including obesity, type-2 diabetes, cardiovascular disease, stroke, and cancer, account for over 60% of deaths worldwide [12, 13], are interrelated at the molecular and cellular levels and share many common risk factors [1416], and, most importantly, are also considered preventable through lifestyle choices of which diet is considered to play a prominent role [1719].

While concern exists that the genetic factors driving the occurrence and progression of cancer and other chronic diseases are so powerful that diet can have little impact, most evidence indicates that the key strategy to conquering chronic diseases like cancer is through prevention particularly when the prevention strategy is routinized from ‘womb to tomb’ (reviewed in [20]). However, in addition to the general presumption that all varieties of a particular staple food crop are created equal with respect to health benefits, one of the challenges of this approach is the assumption that the ingredients which a food is processed into, rather than the food itself, is the most critical factor accounting for health benefits [10]. The work reported in this paper was initiated to provide a resource for evaluating the first premise, that is, that all botanically defined lines of wheat (Triticum and Aegilops species) have equivalent chronic disease fighting activity with anticancer activity providing a focal point for analysis. Cancer was chosen because among these chronic diseases, the prevalence of cancer continues to increase globally and cancer is now the leading cause of chronic disease related mortality in the world [21]; furthermore previously published reports have described an inverse association between wheat consumption and cancer incidence.

Wheat is ranked second, after rice, among all members of the Poaceae family in terms of the amount consumed by the global population [22]. Wheat is used in the preparation of a wide variety of foods for everyday use, including bread, pasta/macaroni/noodles, bulgur, cookies, biscuits, cakes, cereals, pizza, vermicelli, couscous, pastry, and chapatti/flatbread [23, 24]. It is also fermented to make beer and other alcoholic beverages. Wheat’s role as a primary human dietary component is due to its large grain size, agronomic adaptability, ease of storage, and nutritional quality. While a limited number of wheat lines account for most of wheat products consumed globally due to the emergence of global industrial food systems, some ancient wheat lines- such as einkorn and emmer- are still consumed as cereal substitutes in Middle Eastern countries, where wheat is considered to have originated [25]. These grains are very small and difficult to harvest and clean. As such, they are often used in porridge or soup without grinding or processing. In the Arab world (including Iraq, Syria, and Tunisia), soft green (immature) wheat grains, mostly domesticated tetraploid emmer, are sundried and roasted to make a food called Freekeh. In addition, people in Arab countries routinely mix Freekeh made from domesticated landraces of wheat grains with meat and spices in their daily foods.

As noted above, wheat is consumed in large amounts worldwide, but the type of wheat and the manner in which it is consumed differ markedly depending on geographic region. Because of the novel events underlying the domestication of wheat, there are major genetic differences among the types of wheat commonly consumed. As a result of this inherent diversity, the Germplasm Resources Information Network (GRIN) has accumulated over 62,571 wheat-related accessions [26]. The general approach to working with such a large resource is to devise a strategy by which to pick a representative sample of lines from the total resource (collection) that is small enough to manage for use in research yet large enough to capture the diversity of the population for the trait(s) of interest. The resulting subsample of germplasm is referred to as a core collection [27]. Herein, a core collection of wheat lines for future use in chronic disease prevention research is described.

Methods

Source of plant materials

The Triticum and Aegilops collections at GRIN (USDA/ARS, Aberdeen, Idaho) include 59,564 and 2,650 accessions, respectively [26]. Only Triticum and Aegilops were selected for establishing this core collection with the reasoning that these two genera comprise the majority of wheat lines that have emerged due to domestication through natural selection and polyploidization. The accessions chosen for inclusion in the core collection are described in Table 1. All available information was obtained on selected accessions, including passport information, characterization, and evaluation.
Table 1

A summary of the Triticum and Aegilops species used for core collection

Species

Genome

Total active accessions at GRIN

Total number in core collection

Base species (%)

Aegilops speltoides var. speltoides

BB/GG

9

3

33.33

Aegilops speltoides var. ligustica

BB/GG

11

1

9.10

Aegilops tauschii

DD

200

1

0.50

Triticum aestivum subsp. aestivum

BBAuAuDD

46,225

80

0.17

Triticum aestivum subsp. compactum

BBAuAuDD

118

1

0.85

Triticum aestivum subsp. spelta

BBAuAuDD

1,292

6

0.46

Triticum hybrid

BBAADD

219

1

0.46

Triticum monococcum subsp. aegilopoides

AmAm

826

4

0.48

Triticum timopheevii subsp. armeniacum

GGAuAu

249

1

0.40

Triticum turgidum subsp. carthlicum

BBAuAu

95

2

2.11

Triticum turgidum subsp. dicoccon

BBAuAu

622

10

1.61

Triticum turgidum subsp. dicoccoides

BBAuAu

777

2

0.26

Triticum turgidum subsp. durum

BBAuAu

8,526

63

0.74

Triticum turgidum subsp. paleocolchicum

BBAuAu

4

1

25

Triticum turgidum subsp. turanicum

BBAuAu

108

1

0.93

Triticum turgidum subsp. turgidum

BBAuAu

1,054

6

0.57

Triticum urartu

AuAu

245

3

1.22

Triticosecale sp.

BBAuAuRR

1,985

1

0.05

Triticum zhukovskyi

GGAuAuAmAm

6

1

16.67

Total

 

62,571

188

0.30

Criteria of selection

Cancer statistics

The data used were based on GLOBOCAN 2008 cancer statistics [21]. GLOBOCAN’s cancer statistics are based on the incidence of all cancers using the age-standardized rate (ASR). Our intent was to select wheat lines attributed to specific countries identified in the GLOBOCAN global map (Figure 1) that showed wide variations in cancer incidence rates, under the presumption that these wheat lines, and their close relatives, are likely to be consumed in greater amounts in those countries.
https://static-content.springer.com/image/art%3A10.1186%2F2048-7010-2-4/MediaObjects/40066_2012_Article_31_Fig1_HTML.jpg
Figure 1

A world map of cancer incidence displaying geographic distribution of core collection of wheat germplasm. Estimated age-standardized incidence rate (ASR) per 100,000 residents for all cancers, excluding non-melanoma skin cancer, both sexes and all ages based on GLOBOCAN Cancer statistics, 2008. Each black dot represented a wheat growing country of the world. Four colors ranging from very light yellow to dark brown described the ASR from <103.1 to >326.1 per 100,000 individuals.

Centers of origin

Archeological evidence indicates that Armenia, Iran, Iraq, Lebanon, Israel, Jordan, Syria, and Turkey were the centers of origin for wheat germplasm [28]. Cancer statistics also indicated that the occurrence of cancer is very low in these areas, supporting the possibility that the wheat species cultivated and consumed locally provide anticancer protection. Wheat lines from these countries were highly represented in the core collection.

Regression analysis

To determine whether the relationship between wheat consumption and cancer incidence was related to geographic origin of wheat, data were collected from the Food and Agriculture Organization of the United Nations (FAOSTAT) from 2007, operationally defined as kg wheat products consumed per capita per year, and from the GLOBOCAN resource from 2008, operationally defined as ASR of cancer incidence at all sites excluding non-melanoma skin cancer. Countries without data for both parameters were excluded from analyses, resulting in a total of 165 countries for the global analysis (Figure 2A) and a subset of the global analysis using 19 Near Eastern countries which are geographically proximate to the origin of wheat (Figure 2B). The countries included in the latter analysis were Armenia, Azerbaijan, Cyprus, Egypt, Georgia, Iran, Israel, Jordan, Kuwait, Lebanon, Pakistan, Saudi Arabia, the Syrian Arab Republic, Tajikistan, Turkey, Turkmenistan, United Arab Emirates, Uzbekistan, and Yemen. No wheat consumption data were available for Iraq through FAOSTAT. Log10-transformed ASRs were regressed on wheat consumption data (10 kg/capita/year) in linear regression analysis using GraphPad Prism vs. 5.02 (GraphPad Software, San Diego, CA, USA). Fit parameters for each analysis, including slope, Y-intercept, R2, and line equations are provided in the figure legend (Figure 2).
https://static-content.springer.com/image/art%3A10.1186%2F2048-7010-2-4/MediaObjects/40066_2012_Article_31_Fig2_HTML.jpg
Figure 2

Linear regression analysis of association between wheat consumption and cancer incidence rates. To determine whether the relationship between wheat consumption and cancer incidence was related to geographic origin of wheat, 2007 wheat consumption data was collected from FAOSTAT, defined as kg wheat products consumed per capita per year, and from the GLOBOCAN resource from 2008, defined as age-standardized rates (ASR) per 100,000 of cancer incidence at all sites excluding non-melanoma skin cancer. ASRs were log10-transformed to satisfy statistical criteria. Countries without data for both parameters were excluded from analyses. (A) All-site cancer incidence ASRs for 165 countries were regressed against yearly wheat consumption, which showed a slightly positive correlation between wheat consumption and cancer incidence. Slope = 0.008940 ± 0.002527; Y-intercept = 2.120 ± 0.02197; R2 = 0.07131; line equation: Log10-transformed ASR = 0.008940*wheat consumption + 2.120. (B) A subset of the global analysis, comprising ASRs for n=19 Near Eastern countries, which are geographically proximate to the origin of wheat, were regressed against wheat consumption data, which showed a slightly negative correlation between wheat consumption and cancer incidence. Slope = −0.006526 ± 0.008315; Y-intercept= 2.187 ± 0.1225; R2 = 0.03497; line equation: Log10-transformed ASR = −0.006526*wheat consumption + 2.187. Analyses were performed using the linear regression analysis function in GraphPad Prism vs. 5.02 (GraphPad Software, San Diego, CA, USA).

Other considerations

The species of Triticum and Aegilops include germplasm with three ploidy levels: diploid with genomes Am, B, D, and G; tetraploid with BAu and GAu genomes; and hexaploid with BAuD genomes [28]. Selections within each genome and ploidy level were represented in the core collection.

Results and discussion

To our knowledge, there are no published core collections of wheat that have been specifically developed to permit the investigation of wheat for human health benefits and particularly for reducing chronic disease risk using anticancer activity as a screening tool. Thus, the approach used was necessarily descriptive in nature. Rather than enforcing established criteria usually implemented for the development of a core collection for agronomic traits such as disease or pest resistance, or post-harvest processing characteristics [27], cancer incidence data drove variety selection with secondary consideration of ploidy, center of origin, and climate.

Cancer statistics

A world map generated from the GLOBOCAN cancer database is shown (Figure 1) and was used to identify the countries from which germplasm was selected from the GRIN domain collection. Based on GLOBOCAN 2008 statistics, the lowest incidence rates of cancer occur in middle Africa, northern Africa, south central Asia, western Africa, eastern Africa, Central America, and western Asia. Interestingly, western Asia, or the Fertile Crescent region between the Tigris and Euphrates river basins, has been determined to be the geographic center of origin for wheat [28]. To explore the relationship between wheat consumption and cancer incidence as it relates to geographic origin of wheat, we used linear regression analysis. When cancer incidence rates for 165 countries were regressed on wheat consumption data in those countries, a slight positive correlation between these parameters was found (Figure 2A, slope = +0.0089 increase in log10-transformed ASR per 10 kg/capita/year increase in wheat consumption). This translates to an increase of 1.02% in cancer incidence for each 10 kg/capita/year increase in wheat consumption. Conversely, when this analysis was confined to 19 countries near the geographic origin of wheat, a slight negative correlation (Figure 2B, slope = −0.0065 increase in log10-transformed ASR per 10 kg/capita/year increase in wheat consumption). This translates to a reduction of 0.99% in cancer incidence for each 10 kg/capita/year increase in wheat consumption. Hence, the slightly positive association between global cancer incidence rates and wheat consumption is reversed when the analysis is restricted only to countries near the geographic origin of wheat (P <0.01). Many other factors are likely involved in the observed correlations between global wheat consumption and cancer incidence rates. Thus, it is important to underscore that there is no evidence of a causal link between these parameters but rather these analyses support the use of cancer incidence by geographic locale as an objective albeit arbitrary tool to guide wheat line selection for the core collection.

The core collection of wheat germplasm was selected from regions with lower incidence rates of cancer, as well as regions such as North America, Europe, and Oceania (Australia and New Zealand) with higher incidence rates of cancer; evaluation of germplasm from regions of both low and high cancer rates is critical for assessing differences in the type of wheat consumed which may impact cancer activity. In choosing multiple selections from within a country, we were unable to follow the procedure of constant, proportional, and logarithmic selection, as all genotypes were not available in each country [27]. In addition, maintaining uniform diversity around the world was impossible as there are large differences in the total number of accessions in each country that was considered.

Characterization of selected lines

A total of 62,571 accessions at GRIN were designated as the source collection, which represented two genera and 14 taxa. From the source collection, 188 accessions were selected for the core collection, which is 0.3% of the source collection. The global distribution of the wheat lines in the core collection is shown (Figure 1, Table 1) and provides a summary of the Triticum and Aegilops species comprising the core collection. The core collection consisted of two genera and 14 taxa of 10 species and was comprised of 19 groups. These 188 accessions belonged to 82 different countries with three different climates (tropical, subtropical, and temperate). The plant introduction number, plant name, taxon, original source, selection criteria, growth habit, and probable market classes are shown (Table 2). Probable market classes were determined by visual observation of the germplasm using a grain color standard and may be changed during future evaluation.
Table 2

Detailed information for 188 Triticum and Aegilops germplasm collected from GRIN platform through USDA

No.

ID

Plant name

Taxon

Country

Selection criteria

Growth habit

Probable market class

1

PI 542274

84TK081-057

A. speltoides var. speltoides

Turkey

Center of origin

NA

NA

2

PI 560529

TU85-008-01

A. speltoides var. speltoides

Turkey

Center of origin

NA

NA

3

PI 449338

AE 081D

A. speltoides var. speltoides

Israel

Center of domestication

NA

NA

4

PI 560528

TU85-015-02-2

A. speltoides var. ligustica

Turkey

Center of origin

NA

NA

5

PI 603233

TA 1669

A. tauschii

Azerbaijan

D genome donor

NA

NA

6

CItr 180

China

T. aestivum subsp. aestivum

China

Least breast cancer, highest producer of wheat

W

SRW

7

CItr 14319

India Hybrid 65

T. aestivum subsp. aestivum

India

Least breast cancer, second highest producer of wheat

S

SWS

8

CItr 15136

American 378

T. aestivum subsp. aestivum

Sudan

Northern Africa

S

SWS

9

PI 9871

Erivan

T. aestivum subsp. aestivum

Armenia

Center of origin

S

HRS

10

PI 9872

Galgalos

T. aestivum subsp. aestivum

Armenia

Center of origin

S

SWS

11

PI 52323

Little Joss

T. aestivum subsp. aestivum

UK

Northern Europe

W

SRW

12

PI 54431

Triminia

T. aestivum subsp. aestivum

Libya

Middle East

S

HRS

13

PI 62004

NA

T. aestivum subsp. aestivum

China

Least breast cancer

F

NA

14

PI 81791

Sapporo Haru Komugi Jugo

T. aestivum subsp. aestivum

Japan

Eastern Asia

S

SWS

15

PI 82469

Poubiru

T. aestivum subsp. aestivum

North Korea

Eastern Asia

S

HRS

16

PI 87117

Ejuiea

T. aestivum subsp. aestivum

South Korea

Eastern Asia

W

HRW

17

PI 94418

99

T. aestivum subsp. aestivum

Russia

Fourth highest producer of wheat

W

HRW

18

PI 116232

Solid Straw Tuscan

T. aestivum subsp. aestivum

NZ

High cancer incidence

W

SWW

19

PI 124818

Cross No. 7

T. aestivum subsp. aestivum

NZ

High cancer incidence

S

HRS

20

PI 139599

Egypt NA 101

T. aestivum subsp. aestivum

Egypt

Western Asia

S

SWS

21

PI 155315

Yemen

T. aestivum subsp. aestivum

Yemen

Western Asia

S

SRS

22

PI 165208

Sert Bolvadin

T. aestivum subsp. aestivum

Turkey

Center of origin

S

SWS

23

PI 178383

6256

T. aestivum subsp. aestivum

Turkey

Center of origin

W

SRW

24

PI 184994

Snogg II

T. aestivum subsp. aestivum

Norway

Northern Europe

S

HRS

25

PI 190451

Snogg

T. aestivum subsp. aestivum

Norway

Northern Europe

S

SRS

26

PI 191334

Marzuolo 87

T. aestivum subsp. aestivum

Italy

Southern Europe

W

HWW

27

PI 265482

Olympia

T. aestivum subsp. aestivum

Finland

Northern Europe

S

SWS

28

PI 266879

S995

T. aestivum subsp. aestivum

Iraq

Center of origin

S

HWS

29

PI 266880

S997

T. aestivum subsp. aestivum

Iraq

Center of origin

S

HRS

30

PI 274505

NA

T. aestivum subsp. aestivum

Thailand

South Eastern Asia

S

SWS

31

PI 283150

Horani Nawawi

T. aestivum subsp. aestivum

Jordan

Center of origin

S

SWS

32

PI 297005

AFRICA MAYO

T. aestivum subsp. aestivum

Kenya

Eastern Africa

S

HRS

33

PI 347003

White Shanazi

T. aestivum subsp. aestivum

Afghanistan

South Central Asia

S

SWS

34

PI 350308

DACIA

T. aestivum subsp. aestivum

Romania

Eastern Asia

W

HRW

35

PI 384399

Nigeria-2

T. aestivum subsp. aestivum

Nigeria

Western Africa

S

HWS

36

PI 406475

2

T. aestivum subsp. aestivum

Nepal

South Central Asia

S

HRS

37

PI 414975

No. 6

T. aestivum subsp. aestivum

Indonesia

South Central Asia

S

HRS

38

PI 480034

MG 31147

T. aestivum subsp. aestivum

Ethiopia

Eastern Africa

S

SWS

39

PI 487292

SY 270

T. aestivum subsp. aestivum

Jordan

Center of origin

S

HRS

40

PI 519554

PAKISTAN 20

T. aestivum subsp. aestivum

Kenya

Eastern Africa

S

SWS

41

PI 532053

96

T. aestivum subsp. aestivum

Egypt

Northern Africa

S

SWS

42

PI 585019

15007

T. aestivum subsp. aestivum

Saudi Arabia

Western Asia

S

HRS

43

PI 585024

15063

T. aestivum subsp. aestivum

Saudi Arabia

Western Asia (a part of Core 95)

S

HRS

44

PI 603919

UCRBW98-2

T. aestivum subsp. aestivum

USA

DNA segment from Spelta and HWS Pavon (bread wheat), Northern America, a part of core 6

S

SWS

45

PI 648392

KUNDAN

T. aestivum subsp. aestivum

India

Least breast cancer, second highest producer of wheat

S

HWS

46

CItr 14352

II-50-25

T. aestivum subsp. aestivum

Paraguay

South America

S

HRS

47

PI 10611

Talimka

T. aestivum subsp. aestivum

Turkmenistan

South Central Asia

S

HWS

48

PI 61693

294

T. aestivum subsp. aestivum

Malawi

Eastern Africa

S

HWS

49

PI 91235

Cagayan

T. aestivum subsp. aestivum

Philippines

South East Asia

S

HRS

50

PI 125088

Ile de France

T. aestivum subsp. aestivum

France

Western Europe, more cancer

S

HWS

51

PI 174657

Ile de France

T. aestivum subsp. aestivum

France

Western Europe, more cancer

S

SRS

52

PI 182665

9915

T. aestivum subsp. aestivum

Lebanon

Western Asia

S

HWS

53

PI 191701

B 256 F.S. 1354

T. aestivum subsp. aestivum

Mozambique

Eastern Africa

F

SWS

54

PI 191744

FL S Aurora

T. aestivum subsp. aestivum

Mozambique

Eastern Africa

S

SWS

55

PI 203081

Sabanero

T. aestivum subsp. aestivum

Tanzania

Eastern Africa

S

HRS

56

PI 231115

II-2734-2c(1–2)x2T

T. aestivum subsp. aestivum

Guatemala

Central America

S

HRS

57

PI 234233

Idaho 1877 NR AE

T. aestivum subsp. aestivum

Zambia

Eastern Africa

S

HRS

58

PI 278386

Morocco 58

T. aestivum subsp. aestivum

Morocco

Northern Africa

S

HRS

59

PI 278395

Poland 2

T. aestivum subsp. aestivum

Poland

Eastern Europe

W

HRW

60

PI 313098

Quern

T. aestivum subsp. aestivum

Ireland

Northern Europe

S

HRS

61

PI 344018

Mistura Pinto

T. aestivum subsp. aestivum

Angola

Middle Africa, least cancers

S

SWS

62

PI 344019

Saraiva Vieira

T. aestivum subsp. aestivum

Angola

Middle Africa, least cancers

S

SWS

63

PI 351474

Reval

T. aestivum subsp. aestivum

Estonia

Northern Europe

W

HRW

64

PI 351870

10180-54-29

T. aestivum subsp. aestivum

Burundi

Eastern Africa

S

SWS

65

PI 374248

BOL-17

T. aestivum subsp. aestivum

Chad

Middle Africa, least cancers

S

HRS

66

PI 374249

BOL-19

T. aestivum subsp. aestivum

Chad

Middle Africa, least cancers

S

HRS

67

PI 374254

34335

T. aestivum subsp. aestivum

Mali

Western Africa

S

HWS

68

PI 384399

Nigeria-2

T. aestivum subsp. aestivum

Nigeria

Western Africa

S

HWS

69

PI 410425

ILICHEVKA

T. aestivum subsp. aestivum

Kazakhstan

South Central Asia

W

SRW

70

PI 428690

LEUCURUM 3

T. aestivum subsp. aestivum

Uzbekistan

South Central Asia

S

SRS

71

PI 470905

MG 18060

T. aestivum subsp. aestivum

Algeria

Northern Africa

S

SWS

72

PI 480481

R-124

T. aestivum subsp. aestivum

Bolivia

South America

S

SRS

73

PI 481713

41

T. aestivum subsp. aestivum

Bhutan

South Central Asia

W

HRW

74

PI 481715

Ka

T. aestivum subsp. aestivum

Bhutan

South Central Asia

S

SWS

75

PI 486155

CHIWORE

T. aestivum subsp. aestivum

Zimbabwe

Eastern Africa, least breast cancer

S

HRS

76

PI 486156

GWEBI

T. aestivum subsp. aestivum

Zimbabwe

Eastern Africa, least breast cancer

S

SWS

77

PI 486157

RUSAPE

T. aestivum subsp. aestivum

Zimbabwe

Eastern Africa, least breast cancer

S

HRS

78

PI 490405

Koira alkuna

T. aestivum subsp. aestivum

Mali

Western Africa

S

HWS

79

PI 494926

ZFA 3145

T. aestivum subsp. aestivum

Zambia

Eastern Africa

S

HRS

80

PI 532301

Alas

T. aestivum subsp. aestivum

Oman

Western Asia

S

SRS

81

PI 573754

NSGC 531

T. aestivum subsp. aestivum

Hondurus

Central America

S

HRS

82

PI 591964

EMBRAPA 16

T. aestivum subsp. aestivum

Brazil

South America

S

HRS

83

PI 639354

TJK03-128

T. aestivum subsp. aestivum

Tazikistan

South Central Asia

S

SWS

84

PI 648894

Dickson's No. 444

T. aestivum subsp. aestivum

Argentina

South America

S

HWS

85

Cltr 14108

Chinese Spring

T. aestivum subsp. aestivum

USA

Northern America

S

SRS

86

PI 434642

TINCURRIN

T. aestivum subsp. compactum

Australia

More cancer especially skin cancer

S

Club wheat

87

PI 190963

Spelta Hohenheim

T. aestivum subsp. spelta

Portugal

Southern Europe

S

Spelt

88

PI 348710

69Z6.894

T. aestivum subsp. spelta

Spain

Southern Europe

S

Spelt

89

PI 355625

Spelta 34

T. aestivum subsp. spelta

Belgium

Western Europe

S

Spelt

90

PI 591895

NA

T. aestivum subsp. spelta

Germany

Central Europe

W

Spelt

91

PI 367199

128

T. aestivum subsp. spelta

Afghanistan

Central Asia

W

Spelt

92

PI 538510

G2830

T. monococcum subsp. aegilopoides

Iraq

Center of origin, Western Asia

S

Wild einkorn

93

PI 167526

2485

T. monococcum subsp. aegilopoides

Turkey

Western Asia

S

Wild einkorn

94

PI 266844

87

T. monococcum subsp. aegilopoides

Uk

Northern Europe

S

Wild einkorn

95

PI 427990

G3114

T. monococcum subsp. aegilopoides

Lebanon

Center of domestication

W

Wild einkorn

96

PI 427304

G1764

T. timopheevii subsp. armeniacum

Armenia

Center of origin, Western Asia

W

Wild timopheevii

97

PI 538478

G2633

T. timopheevii subsp. armeniacum

Iraq

Center of domestication

W

Wild timopheevii

98

PI 70738

22

T. turgidum subsp. carthlicum

Iraq

Center of origin, Western Asia

S

Persian wheat

99

PI 532501

H83-1537

T. turgidum subsp. carthlicum

Soviet Union

 

S

Persian wheat

100

PI 471808

G-485-5 M

T. turgidum subsp. dicoccoides

Israel

Center of domestication

W

Wild emmer

101

PI 471778

G-40-1-2B-1 M

T. turgidum subsp. dicoccoides

Israel

Center of domestication

W

Wild emmer

102

PI 2789

Yaroslav Spring

T. turgidum subsp. dicoccon

Russia

Fourth highest producer of wheat

S

Cultivated emmer

103

PI 73388

2868

T. turgidum subsp. dicoccon

Armenia

Center of origin, Western Asia

S

Cultivated emmer

104

PI 79899

N-64

T. turgidum subsp. dicoccon

China

Least breast cancer, highest producer of wheat

S

Cultivated emmer

105

PI 190920

2323A

T. turgidum subsp. dicoccon

Portugal

Southern Europe

S

Cultivated emmer

106

PI 191390

Rufum

T. turgidum subsp. dicoccon

Ethiopia

Eastern Africa

S

Cultivated emmer

107

PI 308879

NA

T. turgidum subsp. dicoccon

Spain

Southern Europe

S

Cultivated emmer

108

PI 355483

T 563

T. turgidum subsp. dicoccon

Spain

Southern Europe

S

Cultivated emmer

109

PI 355485

T 567

T. turgidum subsp. dicoccon

Spain

Southern Europe

S

Cultivated emmer

110

PI 499973

KU 1533

T. turgidum subsp. dicoccon

Armenia

Center of origin, Western Asia

S

Cultivated emmer

111

PI 154582

NA

T. turgidum subsp. dicoccon

Taiwan

Eastern Asia

S

Cultivated emmer

112

CItr 15185

Hudeiba 154

T. turgidum subsp. durum

Sudan

Northern Africa

S

Durum or macaroni

113

PI 9130

Saragolla

T. turgidum subsp. durum

Italy

Southern Europe

S

Durum or macaroni

114

PI 54432

Tripshiro

T. turgidum subsp. durum

Libya

Northern Africa

S

Durum or macaroni

115

PI 67341

Huguenot

T. turgidum subsp. durum

Australia

More cancer especially skin cancer

S

Durum or macaroni

116

PI 78809

CI 10107

T. turgidum subsp. durum

Georgia

Western Asia

S

Durum or macaroni

117

PI 81792

Marching No. 8

T. turgidum subsp. durum

Japan

Eastern Asia

S

Durum or macaroni

118

PI 94701

390

T. turgidum subsp. durum

Ancient Palestine

Western Asia

S

Durum or macaroni

119

PI 133459

Durum H2

T. turgidum subsp. durum

Egypt

Center of origin, Northern Africa

S

Durum or macaroni

120

PI 153726

Sicilian

T. turgidum subsp. durum

N. Africa

Less cancers

S

Durum or macaroni

121

PI 157955

Francesone

T. turgidum subsp. durum

Italy

Southern Europe

S

Durum or macaroni

122

PI 174645

Huguenot

T. turgidum subsp. durum

Australia

More cancer especially skin cancer

S

Durum or macaroni

123

PI 182113

S-44

T. turgidum subsp. durum

Pakistan

South Central Asia

S

Durum or macaroni

124

PI 184532

Russia

T. turgidum subsp. durum

Russia

Europe

S

Durum or macaroni

125

PI 208908

Mendola

T. turgidum subsp. durum

Iraq

Center of origin

S

Durum or macaroni

126

PI 208910

Sin El-Jamil

T. turgidum subsp. durum

Iraq

Center of origin

S

Durum or macaroni

127

PI 210848

7979

T. turgidum subsp. durum

Iran

South Central Asia

S

Durum or macaroni

128

PI 221702

11

T. turgidum subsp. durum

Indonesia

Southern Eastern Asia

S

Durum or macaroni

129

PI 231380

Saragolla

T. turgidum subsp. durum

Italy

Oldest durum variety in Italy

S

Durum or macaroni

130

PI 261823

Namra

T. turgidum subsp. durum

Saudi Arabia

Western Asia

S

Durum or macaroni

131

PI 265017

796

T. turgidum subsp. durum

Serbia

Southern Europe

S

Durum or macaroni

132

PI 278223

Gartons Early Cone

T. turgidum subsp. durum

UK

Northern Europe

W

Durum or macaroni

133

PI 278258

Greece 1

T. turgidum subsp. durum

Greece

Southern Europe

S

Durum or macaroni

134

PI 278509

Valencia 6

T. turgidum subsp. durum

Spain

Southern Europe

S

Durum or macaroni

135

PI 278553

Tripolitco

T. turgidum subsp. durum

Cyprus

Western Asia

S

Durum or macaroni

136

PI 283853

China 34

T. turgidum subsp. durum

China

Least breast cancer, highest producer of wheat

S

Durum or macaroni

137

PI 306571

R.S.N.

T. turgidum subsp. durum

Italy

Southern Europe

S

Durum or macaroni

138

PI 325850

PW 3

T. turgidum subsp. durum

India

Least breast cancer, second highest producer of wheat

S

Durum or macaroni

139

PI 361149

Bijaga Yellow

T. turgidum subsp. durum

India

Least breast cancer, second highest producer of wheat

S

Durum or macaroni

140

PI 362046

C 1138/63

T. turgidum subsp. durum

Romania

Eastern Europe

W

Durum or macaroni

141

PI 422295

QUILAFEN

T. turgidum subsp. durum

Chile

South America

S

Durum or macaroni

142

PI 422297

SINCAPE 90

T. turgidum subsp. durum

Italy

Southern Europe

S

Durum or macaroni

143

PI 422312

MACS-45

T. turgidum subsp. durum

India

Least breast cancer, second highest producer of wheat

S

Durum or macaroni

144

PI 428458

Egypt Local No. 8

T. turgidum subsp. durum

Egypt

Center of origin, Northern Africa

S

Durum or macaroni

145

PI 428468

JORDAN 38

T. turgidum subsp. durum

Jordan

Center of origin, Western Asia

S

Durum or macaroni

146

PI 428469

JORDAN 40

T. turgidum subsp. durum

Jordan

Center of origin, Western Asia

S

Durum or macaroni

147

PI 462107

172

T. turgidum subsp. durum

Yemen

Western Asia

S

Durum or macaroni

148

PI 480347

MG 31577

T. turgidum subsp. durum

Ethiopia

Eastern Africa

S

Durum or macaroni

149

PI 496260

MEDORA

T. turgidum subsp. durum

Canada

North America

S

Durum or macaroni

150

PI 519864

DURUM VARIETY 24

T. turgidum subsp. durum

Mexico

North America

S

Durum or macaroni

151

PI 520393

TUNISIAN DURUM 1

T. turgidum subsp. durum

Tunisia

Northern Africa

S

Durum or macaroni

152

PI 520394

TUNISIAN DURUM 8

T. turgidum subsp. durum

Tunisia

Northern Africa

S

Durum or macaroni

153

PI 520414

ICD 7780-5AP-OSH-OAP

T. turgidum subsp. durum

Syria

Center of origin, Western Asia

S

Durum or macaroni

154

PI 520415

SYRIAN DURUM 27

T. turgidum subsp. durum

Syria

Center of origin, Western Asia

S

Durum or macaroni

155

PI 542464

SHORT SARAGOLLA

T. turgidum subsp. durum

USA

High cancer incidence

S

Durum or macaroni

156

PI 585025

15017

T. turgidum subsp. durum

Saudi Arabia

Western Asia

S

Durum or macaroni

157

CItr 14374

497-360

T. turgidum subsp. durum

Lebanon

Western Asia

S

Durum or macaroni

158

CItr 14802

ELS 6404-122

T. turgidum subsp. durum

Eritrea

Eastern Africa

S

Durum or macaroni

159

PI 5465

Candeal

T. turgidum subsp. durum

Argentina

South America

F

Durum or macaroni

160

PI 5639

Kubanka

T. turgidum subsp. durum

Kazakhstan

South Central Asia, largest consumer of wheat

S

Durum or macaroni

161

PI 35314

1809a

T. turgidum subsp. durum

Kyrgyzstan

South Central Asia

F

Durum or macaroni

162

PI 50929

933

T. turgidum subsp. durum

Kyrgyzstan

South Central Asia

S

Durum or macaroni

163

PI 61108

6951

T. turgidum subsp. durum

Turkmenistan

South Central Asia

S

Durum or macaroni

164

PI 89642

NA

T. turgidum subsp. durum

Hondurus

Central America

S

Durum or macaroni

165

PI 278384

Morocco C10895

T. turgidum subsp. durum

Morocco

Northern Africa

W

Durum or macaroni

166

PI 286066

NA

T. turgidum subsp. durum

Poland

Eastern Europe

S

Durum or macaroni

167

PI 384401

Wurno 2

T. turgidum subsp. durum

Nigeria

Western Africa

S

Durum or macaroni

168

PI 519759

D 73121

T. turgidum subsp. durum

Algeria

Northern Africa

S

Durum or macaroni

169

PI 520164

ALGERIA LINE 47

T. turgidum subsp. durum

Algeria

Northern Africa

S

Durum or macaroni

170

PI 532289

Musane

T. turgidum subsp. durum

Oman

Western Asia

S

Durum or macaroni

171

PI 565208

Chaggo

T. turgidum subsp. durum

Bolivia

South America

S

Durum or macaroni

172

PI 592019

VATAN

T. turgidum subsp. durum

Uzbekistan

South Central Asia

S

Durum or macaroni

173

PI 654290

TJK2006:296

T. turgidum subsp. durum

Tazikistan

South Central Asia

S

Durum or macaroni

174

Cltr 13165

Langdon

T. turgidum subsp. durum

USA

Northern America

W

Durum or macaroni

175

PI 330553

189

T. turgidum subsp. paleocolchicum

UK

Northern Europe

S

Cultivated emmer

176

PI 211708

Egypt

T. turgidum subsp. turanicum

Egypt

Center of origin, Northern Africa

S

Khorasan or oriental

177

PI 166591

Ak

T. turgidum subsp. turgidum

Turkey

Center of origin

S

Rivet or cone

178

PI 167867

4314

T. turgidum subsp. turgidum

Turkey

Center of origin

S

Rivet or cone

179

PI 481591

IQ 223

T. turgidum subsp. turgidum

Iraq

Center of origin

S

Rivet or cone

180

PI 502933

Fo Shou Mai

T. turgidum subsp. turgidum

China

Largest producer

S

Rivet or cone

181

PI 208912

Zerdakia

T. turgidum subsp. turgidum

Iraq

Center of origin

S

Rivet or cone

182

PI 438971

AKMOLINKA 2

T. turgidum subsp. turgidum

Kazakhstan

South Central Asia

S

Rivet or cone

183

PI 427328

G2264

T. urartu

Iraq

Center of origin

S

Wild einkorn

184

PI 428183

G1759

T. urartu

Armenia

Center of origin

S

Wild einkorn

185

PI 428279

G3162

T. urartu

Lebanon

Center of domestication

W

Wild einkorn

186

PI 355707

69Z5.72

T. zhukovskyi

Georgia

Donor for GG genome and cross between T. timopheevi and T. monococcum

W

Cultivated hexaploid

187

PI 429099

6A-696

Triticosecale sp.

Germany

Cross between T. dicoccum & S. cereale; hexaploid

F

Tritical (Rye and durum cross)

188

PI 574284

ASVM4*4654

T. hybrid

USA

High cancer incidence

S

Aegilops squarrosa/T. dicoccum

A, Aegilops; F, Facultative; HRW, Hard red winter; HRS, Hard red spring; HWS, Hard white spring; HWW, Hard white winter; NA, not available; S, Spring; W, Winter; SRS, Soft red spring; SRW, Soft red winter; SWS, Soft white spring; SWW, Soft white winter; T, Triticum.

Climate

There are several climates in which the domestication of wheat occurred: tropical, subtropical, and temperate, and three types of wheat resulted: winter, spring, and facultative. They differ in temperature response due to the presence and absence of dominant vernalization genes [29, 30]. The three types of wheat are presented in the core collection.

Limitations

Cancer prevalence rates among countries are subject to a host of genetic and environmental determinants. Despite associations reported between wheat consumption and cancer risk, there is no direct causal evidence that a particular wheat variety reduces the cancer rate within a specific country [19]. Nonetheless, the overall cancer rate in a country provided an objective albeit arbitrary criterion for selecting wheat lines for inclusion in the core collection. The usefulness of this approach will be determined as screening for anticancer activity in laboratory model systems progresses. Another limitation is that many core collections of crop species are between 5% and 10% of the domain in size, and thus the core collection reported is relatively small in comparison (Table 1). However, there are examples of core collections <5% of the domain in size. For example, the international barley core collection is approximately 0.3% of the world barley holding, and the ICRISAT (International Crops Research Institute for the Semi Arid Crops, Hyderabad, India) sorghum core collection is about 1.5% of the domain size [31, 32]. As many of the lines shown (Table 2) are wild accessions, data are not available on genetic and metabolic markers, agronomic and morphological characteristics, thus limiting the descriptive information provided.

Future direction

Having established this core collection and obtained grain for each line from GRIN, the next step in the identification of distinct wheat lines with enhanced biomedical activity is the interrogation of these lines via phytochemical profiles using LC-TOF-MS analysis of wheat grain extracts according to our recently published procedures [9]. The chromatographic data that result will be subjected to advanced multivariate regression techniques that plot multidimensional relationships to define the chemical diversity within the core collection. The same extracts used for metabolic profiling will then be subjected to in-vitro biological analysis to assign a relative value for anticancer activity to each wheat line. For wheat lines with the greatest in-vitro activity, in-vivo testing in appropriate animal cancer models will be conducted. For wheat lines with in-vivo anticancer activity, the genetic and metabolomic traits that account for protection will be identified and appropriate experiments conducted to determine the extent to which environmental factors impact the stable expression of the traits of interest [10].

Conclusion

While there has been an active discussion of adding value to wheat through the enhancement of its human health benefits, no systematic approaches have been establish to advance this effort. The work reported herein constitutes the first essential step needed to examine wheat germplasm resources in order to identify health benefits that may exist and to develop them fully for the benefit of the consuming public.

Availability of supporting data

The datasets supporting the results of this article are available in the Germplasm Resources Information Network (GRIN) repository from the United States Department of Agriculture (USDA), http://​www.​ars-grin.​gov/​npgs/​index.​html; in the Food and Agriculture Organization of the United States (FAOSTAT) repository from the World Health Organization, http://​faostat3.​fao.​org/​home/​index.​html#COMPARE; and in the GLOBOCAN repository from the International Agency for Research on Cancer (IARC), http://​globocan.​iarc.​fr.

Authors’ information

MS is a Research Associate in the Department of Soil and Crop Sciences, SM is a doctoral candidate in the Cell and Molecular Biology Program, and HT directs the Cancer Prevention Laboratory at Colorado State University.

Abbreviations

ASR: 

Age-standardized rate per 100,000 individuals

CC: 

Core collection

GRIN: 

Germplasm Resources Information Network

mt: 

Metric tons

PI: 

Plant introduction.

Declarations

Acknowledgments

The authors would like to thank Dr. Harold Bockelman for providing wheat germplasm from GRIN, the International Agency for Research on Cancer for allowing us to use the GLOBOCAN cancer map, and Stephanie MacLeaod and John McGinley for their assistance in the preparation of this manuscript. The authors would also like to thank Colorado State University Libraries Open Access Research and Scholarship program for providing funds for publication.

Authors’ Affiliations

(1)
Cancer Prevention Laboratory, Colorado State University 1173 Campus Delivery

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Copyright

© Santra et al.; licensee BioMed Central Ltd. 2013

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://​creativecommons.​org/​licenses/​by/​2.​0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.