GM Crop Database

Database Product Description

4114 (DP-ØØ4114-3)

Host Organism: Zea mays (Maize)

Trait: Herbicide tolerant, glufosinate ammonium; Insect resistant, Coleoptera; Insect resistant, Lepidoptera.

Trait Introduction: Agrobacterium tumefaciens-mediated plant transformation.

Proposed Use: Production for human consumption and livestock feed.

Product Developer: Pioneer Hi-Bred International Inc.

Summary of Regulatory Approvals

Country	Food	Feed	Environment	Notes
Australia	2015
Canada	2013	2013	2013
Colombia	2016
Japan	2015	2015
Korea	2014	2014
Mexico	2014	2014
New Zealand	2015
South Africa	2016	2016
Taiwan	2014	2014
United States	2013	2013	2012	View Combined food and feed review.

Introduction Expand: DuPont Pioneer has developed maize line 4114 (DP-ØØ4114-3) as a “molecular stack” equivalent of the “breeding stack” containing the combined traits from maize lines 1507 (DAS-Ø15Ø7-1) and 59122 (DAS-59122-7). Maize line 4114 expresses the same insect-resistance and herbicide-tolerance traits as present in currently commercialized hybrids containing 1507 x 59122, which are marketed under the trade name Herculex® XTRA. Just like Herculex® XTRA hybrids, 4114 maize expresses the Cry1F protein, conferring resistance to certain lepidopteran insect pests (e.g., European corn borer), the Cry34Ab1 and Cry35Ab1 proteins, which together form an active binary insecticidal protein conferring resistance to corn rootworm, and the PAT enzyme, which inactivates glufosinate herbicide via acetylation.
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Unlike the 1507 x 59122 breeding stack, where the DNA insertions carrying traits derived from events 1507 and 59122, respectively, are located at two unlinked genetic loci, the genes encoding the Cry1F, Cry34Ab1, Cry35Ab1, and PAT proteins in 4114 maize are present at a single locus. This allows event 4114 to be bred more efficiently into new product offerings and to serve as a more efficient platform for the production of larger stack combinations through conventional breeding. Efficient breeding of multiple traits is becoming more important as growers demand more complex products, including multiple modes of action for insect control and herbicide-tolerance.

Summary of Introduced Genetic Elements Expand

Code	Name	Type	Promoter, other	Terminator	Copies	Form
pat	phosphinothricin N-acetyltransferase	HT	CaMV 35S	CaMV 35S poly(A) signal	1	Synthetic version of native gene
cry35Ab1	Cry35Ab1 delta-endotoxin	IR	Triticum aestivum peroxidase gene root-preferred promoter	Solanum tuberosum proteinase inhibitor II (PINII)	1 functional	Altered coding sequence for optimal expression in maize
cry34Ab1	Cry34Ab1 delta-endotoxin	IR	Zea mays ubiquitin gene promoter, intron and 5' UTR	Solanum tuberosum proteinase inhibitor II (PINII)	1 functional	Altered coding sequence for optimal expression in maize
cry1Fa2	cry1F delta-endotoxin	IR	ubiquitin (ubi) ZM (Zea mays) promoter and the first exon and intron	3' polyadenylation signal from ORF25 (Agrobacterium tumefaciens)	One copy	Altered coding sequence for optimal expression in plant cells.

Characteristics of Zea mays (Maize) Expand

Center of Origin	Reproduction	Toxins	Allergenicity
Mesoamerican region, now Mexico and Central America	Cross-pollination via wind-borne pollen is limited, pollen viability is about 30 minutes. Hybridization reported with teosinte species and rarely with members of the genus Tripsacum.	No endogenous toxins or significant levels of antinutritional factors.	Although some reported cases of maize allergy, protein(s) responsible have not been identified.

Donor Organism Characteristics Expand

Latin Name	Gene	Pathogenicity
Streptomyces viridochromogenes	pat	S. viridochromogenes is ubiquitous in the soil. It exhibits very slight antimicrobial activity, is inhibited by streptomycin, and there have been no reports of adverse affects on humans, animals, or plants.
Bacillus thuringiensis subsp. kurstaki	cry1Ac	Although target insects are susceptible to oral doses of Bt proteins, there is no evidence of toxic effects in laboratory mammals or bird given up to 10 µg protein / g body wt. There are no significant mammalian toxins or allergens associated with the host organism.
Bacillus thuringiensis strain PS149B1	cry34Ab1	While target insects are susceptible to oral doses of Bt proteins, there is no evidence of toxic effects in laboratory mammals, in birds or in non-target arthropods.
Bacillus thuringiensis var. aizawai	cry1F	While target insects are susceptible to oral doses of Bt proteins, no evidence of toxic effects in laboratory mammals or birds.

Modification Method Expand: Maize line 4114 was produced by Agrobacterium tumefaciens-mediated transformation with plasmid PHP27118 containing the cry1F, cry34Ab1, cry35Ab1, and pat gene expression cassettes. These gene expression cassettes are exactly the same as used in the production of 1507 maize (cry1F, pat) and 59122 maize (cry34Ab1, cry35Ab1, pat). The first cassette contains a truncated version of the cry1F gene from Bacillus thuringiensis var. aizawai. Transcriptional control is provided by the maize polyubiquitin promoter, resulting in constitutive expression of the Cry1F protein in maize. This region also includes the 5' untranslated region (UTR) and intron associated with the native polyubiquitin promoter. The terminator for the cry1F gene is the polyadenylation signal from open reading frame 25 (ORF25) of the A. tumefaciens Ti plasmid pTi15955.
The second cassette contains the cry34Ab1 gene isolated from B. thuringiensis strain PS149B1. The expression of the cry34Ab1 gene is controlled by a second copy of the maize polyubiquitin promoter with 5' UTR and intron. The terminator for the cry34Ab1gene is the 3’ terminator sequence from the proteinase inhibitor II gene (pinIIterminator) of Solanum tuberosum.
The third gene cassette contains the cry35Ab1 gene, also isolated from B. thuringiensisstrain PS149B1. The expression of the cry35Ab1 gene is controlled by the Triticum aestivum (wheat) peroxidase promoter and leader sequence. The terminator for thecry35Ab1 gene is a second copy of the pinII terminator.
The fourth and final gene cassette contains a version of the phosphinothricin N-acetyltransferase (pat) gene from Streptomyces viridochromogenes that has been optimized for expression in plants. Expression of the pat gene is controlled by the promoter and terminator regions from the cauliflower mosaic virus (CaMV) 35S transcript.

Characteristics of the Modification Expand: Molecular Characterization:

Detailed Southern blot analysis of 4114 maize genomic DNA confirmed that the introduced DNA (T-DNA) was incorporated intact into a single site within the maize genome, without truncation or deletion of nucleotide sequences within any of the gene expression cassettes. Based on a combination of genotypic and phenotypic testing, it was determined that the introduced cry1F, cry34Ab1, cry35Ab1, and pat genes were stably inherited across multiple generations, and segregated as a single genetic locus in 4114 maize according to Mendelian rules of inheritance.

Expressed Material:
The Cry1F, Cry34Ab1, Cry35Ab1, and PAT proteins present in 4114 maize are predicted, based on the method of genetic modification and nucleotide sequencing of the introduced DNA, to have the same amino acid sequence as the corresponding proteins in events 1507 and 59122, and by extension, the conventional breeding stack of 1507 x 59122 maize. Protein equivalence was further demonstrated via western immunoblot analysis comparing the molecular weight and immunoreactivity of the Cry1F, Cry34Ab1, Cry35Ab1, and PAT proteins produced either in 4114 maize or in 1507 x 59122 maize. Therefore, previous safety assessments of the Cry1F, Cry34Ab1, Cry35Ab1, and PAT proteins conducted during the reviews of 1507 and 59122 maize are also applicable for 4114 maize. In most cases, the concentrations of Cry1F, Cry34Ab1, Cry35Ab1, and PAT proteins in 4114 maize tissue samples were similar to, or lower than, corresponding concentrations of these proteins in tissue samples from 1507 x 59122 maize. Thus, evaluations of potential environmental exposure to Cry1F, Cry34Ab1, and Cry35Ab1 proteins conducted during the previous assessments of 1507 and 59122 maize are also informative for 4114 maize. Additionally, it is unlikely that any of the differences in the concentrations of Cry1F, Cry34Ab1, or Cry35Ab1 proteins between 4114 and 1507 x 59122 maize are biologically meaningful with respect to potential impact on non-target organisms.

Environmental Safety Considerations Expand: Agronomic and phenotypic evaluations of 4114 maize were conducted in order to support a conclusion of “familiarity” based on the similarity of phenotypic characteristics with conventional and/or control maize. The phenotypic evaluations were based on laboratory experiments, to examine seed dormancy and germination, and replicated, multi-location field trials to collect data on representative characteristics that influence reproductive and survival biology. In each of these assessments, 4114 maize was compared to a near?isogenic control (i.e., ca. 98 percent similar) that did not go through the transformation process, and/or to commercial maize hybrids.

Germination rates of 4114 maize seed under warm, cold, and diurnal conditions were comparable to those of control maize under corresponding conditions. No potentially dormant seed were identified using a standard tetrazolium chloride test, which was applied to any non-germinated seed that were classified as hard or imbibed. Maize line 4114 can therefore be considered comparable to conventional maize with respect to seed germination and potential dormancy.
Comparisons of emergence and vegetative growth parameters between 4114 and control maize were based on assessments of early plant population, seedling vigour, plant height, ear height, stalk lodging, root lodging, final plant population, and stay green. There were no statistically significant differences in any of these parameters between 4114 and control maize.
Potential changes to the reproductive characteristics of 4114 maize were assessed through a combination of laboratory evaluations of seed germination and dormancy (previously described); evaluation of pollen viability, as correlated to pollen shape and colour; and collection of relevant field data on time to silking, time to pollen shed, and yield. In addition, visual estimates of foliar disease incidence and insect damage were collected for both 4114 and control maize at each location. There were no statistically significant differences in any of the parameters related to reproductive biology or disease and pest susceptibility between 4114 and control maize.

Food and/or Feed Safety Considerations Expand: For new varieties without purposefully altered nutritional properties, such as 4114 maize, the compositional assessment is part of the weight-of-evidence approach for evaluating whether there were any unanticipated consequences of the genetic modification.

Compositional analyses were performed on samples of maize forage and kernels (grain) obtained from hybrid plants of 4114 and near-isogenic control maize grown in side-by-side trials across six locations in the United States and Canada in 2010. The near-isogenic control plants had a genetic background that was ca. 98 percent similar to that of the 4114 maize generation used, but did not go through the transformation process.
Among the 82 compositional components that were analyzed in samples of 4114 and near-isogenic control maize grain, and nine components that were analyzed in forage samples, the only statistically significant differences observed were in concentrations of ash, phosphorus, potassium, and eicosenoic acid in grain samples. This number of statistically significant differences is within the range that would be expected purely by chance. The magnitudes of the differences in mean concentrations were small, less than 15 percent, and in every case the mean values from 4114 maize grain samples were within the ranges of natural variation as reported in the literature. Overall, no consistent patterns emerged to suggest that biologically meaningful changes in composition or nutritive value of the grain had occurred as a consequence of the genetic modification, or expression of the Cry1F, Cry34Ab1, Cry35Ab1, and PAT proteins in 4114 maize.
The conclusion based on these data was that grain and forage from 4114 maize were compositionally equivalent to these same products from unmodified near-isogenic control maize, and to other commercial maize hybrids. Processing is unlikely to alter the compositional components of maize grain, thus, products derived from 4114 grain will also be compositionally equivalent to their conventional counterparts.

Links to Further Information Expand

Canadian Food Inspection Agency

Decision Document DD 2013-98: Determination of the Safety of Pioneer Hi-Bred Production Ltd.'s Corn (Zea mays L.) Event 4114
[PDF Size: 227.09K bytes]

Food Safety Commission of Japan

Safety Assessment Report: Glyphosate herbicide tolerant and lepidopteran and coleopteran resistant maize containing event DP-004114-3
[PDF Size: 79.30K bytes]

Food Standards Australia New Zealand (FSANZ)

Approval Report – Application 1106 Food derived from Herbicide-tolerant & Insect-protected Corn Line 4114
[PDF Size: 1.14M bytes]

US Environment Protection Agency

Notice of Pesticide Registration for 4114 Maize

US Food and Drug Administration

Biotechnology Consultation - Note to the File No. 000136 Event 4114 insect-resistant, herbicide tolerant corn

USDA APHIS

This record was last modified on Tuesday, September 6, 2016

Product Related Info

Biology Documents

Biology Info
Biology of Maize L.
General Description

Maize is a tall, monoecious, annual grass varying in height from 1 to 4 meters (Watson & Dallwitz 1992). The main stem is made up of clearly defined nodes and internodes. Internodes are wide at the base and gradually taper to the terminal inflorescence at the top of the plant. Leaf blades are found in an alternating pattern along the stem. Maize is a unique grass as both male and female flowers are borne on the same plant but are located separately. The tassels or staminate (male) inflorescence form large spreading terminal panicles that resemble spike-like racemes. Pollen is shed from the tassel and is viable for approximately 10 to 30 minutes as it is rapidly desiccated in the air (Kiesselbach 1980). Maize plants shed pollen for up to 14 days. The reproductive phase begins when one or two auxiliary buds, present in the leaf axils, develop and form the pistillate inflorescence or female flower (Purseglove 1972). The auxiliary bud starts the transformation to form a long ‘cob’ on which the flowers will be borne. From each flower a style begins to elongate towards the tip of the cob in preparation for fertilization. These styles form long threads, known as silks. The base of the silk is unique, as it elongates continuously until fertilization occurs (Purseglove 1972). Styles may reach a length of 30 cm, the longest known in the plant kingdom. Individual maize kernels, or fruit, are unique in that mature seed is not covered by floral bracts (glumes, lemmas, and paleas) as in most other grasses, but rather the entire structure is enclosed and protected by large modified leaf bracts, collectively referred to as the ear (Hitchcock and Chase 1951). The mature female flowers will remain ready for fertilization for up to two weeks, at which point if fertilization has not occurred, the nucleus will de-organize and fertilization will no longer be possible (Hitchcock & Chase 1951). The pollen of maize, a protandrous plant, matures before the female flower is receptive (Purseglove 1972). This may have been an ancient mechanism to ensure cross-pollination, but is no longer considered conducive to modern agricultural practices. However, decades of conventional selection and improvement have produced many maize varieties with similar maturities for both male and female flowers, to ensure seed set for agricultural proposes.

Reproduction

Under natural conditions, maize reproduces only by seed production. Pollination occurs with the transfer of pollen from the tassels to the silks of the ear. About 95% of the ovules are cross-pollinated and about 5% are self-pollinated (Poehlman 1959), although plants are completely self-compatible. Maize, as a thoroughly domesticated plant, has lost all ability to disseminate its seeds and relies entirely on the aid of man for its distribution (Stoskopf 1985). The kernels are tightly held on the cobs and if ears fall to the ground, so many competing seedlings emerge that the likelihood that any will grow to maturity is extremely low. Maize cannot reproduce asexually by natural means. It is possible to reproduce maize using tissue culture techniques, however, it has proven extremely difficult with a low rate of success (Hoisington et al. 1998).

Classification and Phylogeny of Maize

Zea is a genus belonging to the grass family, Poaceae, in the Andropogoneae tribe, but is commonly cited in literature to belong to the tribe Maydeae. Zea (zeia) was derived from an old Greek name for a food grass. The genus Zea consists of four species of which only Zea mays ssp. mays L. is economically important. The other Zea species, referred to as teosintes, are largely wild grasses native to Mexico and Central America (Doebley 1990). The number of chromosomes in Zea mays is 2n=20, 21, 22, 24 (FAO 2000c). The tribe Maydeae consists of seven genera: two of American origin, Zea and Tripsacum; and five of Eastern origin which extend from India through Southeastern Asia to Australia and include Coix, Sclerachne, Polytoca, Chionachne and Trilobachne (Watson & Dallwitz 1992). It is generally agreed that maize phylogeny was largely determined by the American genera Zea and Tripsacum, however it is accepted that the genus Coix contributed to the phylogenetic development of the species Z. mays (Radu et al. 1997). The genus Manisuris, from the tribe Andropogoneae, may also have contributed to the evolution of Zea mays (Eubanks 1997a; Radu et al. 1997).

Center of Origin and Progenitors of Maize

The center of origin for Zea mays ssp. mays has been established as the Mesoamerican region, now Mexico and Central America (Watson & Dallwitz 1992). The exact period of domestication and the ancestors from which maize arose are unclear. Archaeological records suggest that domestication of maize began at least 6000 years ago, occurring independently in regions of the southwestern United States, Mexico, and Central America (Mangelsdorf 1974). The origins of domesticated maize have been difficult to trace as hybridization events in its evolution are thought to have involved a now extinct wild maize ancestor of which little evidence has been found (Eubanks 1997a).

Germplasm Diversity

A study in 1992 concluded that maize landraces occupied 42% of the land under production in less developed countries (México 1994). Mexico and Central America are the only regions where ancient maize lines, such as pod corn, are found (Mink & Dorosh 1985). The survival of maize landraces has been attributed to the integral role maize sustains in small communities where it has very specific uses for food and other special functions. These landraces have been well characterized in Latin America, and germplasm not yet evaluated is known to be present in the region. There is a growing trend in developing countries to adopt improved maize varieties, primarily to meet market demand. In Mexico, only 20% of the corn varieties grown 50 years ago remain in cultivation (World Watch Institute 2000). The narrowing of genetic diversity in modern maize varieties emphasizes the importance of conserving genetic traits for future plant breeding. Leading the way in preserving maize germplasm is CIMMYT (International Maize and Wheat Improvement Centre), which has the world’s largest collection of maize accessions, with over 17,000 lines (CIMMYT 2000). Collections of distant maize relatives native to Asia have been recommended by conservation experts to ensure their preservation for future research (Sharma 1998).

Relatives of Maize

The closest wild relatives of maize are the teosintes which all belong to the genus Zea. The teosintes are wild grasses native to Mexico and Central America and have limited distribution (Mangelsdorf et al. 1981). Teosinte species show little tendency to spread beyond their natural range and distribution is restricted to North, Central and South America (Watson & Dallwitz 1992). The nearest teosinte relative to Z. mays ssp. mays is Z. mays ssp. mexicana (Schrader) Iltis (previously classified as Euchlaena mexicana, Zea mexicana) (2n = 20). This Central Mexican annual teosinte is a large flowered, mostly weedy grass with a broad distribution across the central highlands of Mexico. It does not spread readily. It has limited use as a forage and green fodder crop, but can be problematic due to weedy tendencies (Doebley 1990, Watson & Dallwitz 1992). The closest wild relatives to maize outside the Zea genus are from the genus Tripsacum. The genus Tripsacum is comprised of about 12 species that are mostly native to Mexico and Guatemala but are widely distributed throughout warm regions in the USA and South America, with some species present in Asia and Southeast Asia (Watson & Dallwitz 1992). All species are perennial, warm season grasses.

Outcrossing

Gene flow from maize can occur by two means: pollen transfer and seed dispersal. Seed dispersal can be readily controlled in maize as domestication has all but eliminated any seed dispersal mechanisms that ancestral maize may have previously used (Purseglove 1972). The kernels are held tightly on the cobs and if the ear falls to the ground, competing seedlings limit growth to maturity (Gould 1968). Pollen movement is the only effective means of gene escape from maize plants. Pollen is released from the tassels at the top of the plant and transported by wind to the female flowers located on the stalk. Pollen shed occurs over a 14 day period, with a peak during the first 5 days of shed (Sears 2000). The stigmas are receptive for a large part of this two week interval (Kiesselbach 1980). Insects, such as bees, have been observed to collect pollen from maize tassels, but they do not play a significant role in cross-pollination as there is no incentive to visit the female flowers (Rayor et al. 1972).

Wind speed and direction affect pollen distribution

Differences in flowering dates among commercial maize varieties are small. Cross-pollination between varieties may occur if grown in adjacent fields. The limited viability of maize pollen reduces the risk of cross-pollination, as a receptive host must be found within the 30 minutes that the pollen remains biologically active. Cross-pollination is also affected by the concentration of maize pollen released; pollen produced by a maize crop will successfully compete with foreign pollen sources when present in higher concentrations (Rayor et al. 1972). The isolation of crops using separation distances and physical barriers are common techniques for restricting gene flow and ensuring seed purity for maize seed production. Cross-pollination is controlled in seed lots by separating different lines. The OECD standards require a minimum 200 m (660 ft) isolation distance for maize seed production. This distance has been estimated to maintain inbred lines at 99.9% purity. Physical barriers, such as trees or barrier rows, are also effective in reducing cross-pollination. Detasseling or bagging the tassel effectively prevents pollen movement and limits gene flow.

Intraspecific hybidization

All forms of Zea mays spp mays, such as dent, sweet, and pop corn, freely cross pollinate forming fertile hybrids (Pursglove 1972).

Interspecific hybridization

All teosintes can be crossed to maize and form fertile hybrids, except for the tetraploid Z. perennis. Maize-teosinte hybrids exhibit low fitness and have little impact on gene introgression in subsequent generations (Galinat 1988). The tendency to form natural hybrids differs among teosintes: Z. luxurians rarely hybridizes with maize, whereas Z. mays ssp. mexicana frequently forms hybrids (Wilkes 1977). Molecular data confirms that there is gene flow between maize and teosinte and suggests that introgression of maize and teosinte occurs in both directions but at low levels (Doebley 1990).

Intergeneric hybridization Tripsacum species (T. dactyloides, T. floridanum, T. lanceolatum, and T. pilosum) have been successfully hand crossed with maize to form hybrids. The hybrids generally have 28 chromosomes, 10 from maize and 18 from Tripsacum, and are pollen sterile with limited female fertility (Mangelsdorf & Reeves 1939, Mangelsdorf 1974). This infertility is common in such wide crosses because of differences in chromosome number and lack of pairing between chromosomes (Eubanks 1997b). Maize readily crosses with hexaploid wheat (Triticum aestivum) with high frequencies of fertilization and embryo formation (plant breeders use maize pollen to develop double haploids of hexaploid wheat). However, maize chromosomes are eliminated from the genome during the initial stages of meiosis and result in haploid embryos. There is little evidence to suggest fertile hybrids between maize and hexaploid wheat could be produced in nature. There have been unsubstantiated reports of hybridization between maize and sugar cane (Saccaharum sp.).

Biology References
1. CIMMYT (International Maize and Wheat Improvement Centre) (2000). CGIAR Research, Areas of Research: Maize (Zea mays L.) http://www.cgiar.org/areas/maize.htm
2. Doebley, J. F. (1990). Molecular Evidence for Gene Flow among Zea species. BioScience 40, 443- 448.
3. Eubanks, M.W. (1997a). Further evidence for two progenitors in the origin of maize. Maize Newsletter 71, 35-35.
4. FAO (2000c). Species Description. Zea mays L. http://www.fao.org/WAICENT/faoinfo/agricult/agp/agpc/doc/gbase/data/pf000342.htm
5. Galinat, W.C. (1988). The origin of corn. In: Corn and Corn Improvement. Agronomy Monographs No.18. American Society of Agronomy, G.F Sprague and J.W. Dudley, (eds.). Madison, Wisconsin, pp. 1-31.
6. Gould, F.W. (1968). Grass Systematics. McGraw Hill, N.Y., USA.
7. Hitchcock, A.S. & A. Chase. (1951). Manual of the Grasses of the United States (Volume 2). Dover Publications: N.Y. p. 790-796.
8. Hoisington, D., Listman, G.M. & Morris, M.L. (1998). Varietal development: applied biotechnology. In: Maize Seed Industries in Developing Countries. M. L. Morris (ed). Lynne Rienner Publishers, Inc. pp. 77-102.
9. Kiesselbach, T.A. (1980). The structure and reproduction of corn. Reprint of: Research Bulletin No. 161. 1949. Agricultural Experiment Station, Lincoln, Nebraska. University of Nebraska Press. p. 93.
10. Laurie, D.A. & Bennett, M.D. (1986). Wheat x maize hybridization. Can. J. Genet. Cytol. 28, 313-316.
11. Mangelsdorf, P. C. & Reeves, R.G. (1939). The origin of Indian corn and its relatives. Texas Agric. Expt. Sta. Bull. 574.
12. Mangelsdorf, P. C. (1974). Corn: its Origin, Evolution and Improvement. Harvard Univ. Press, Cambridge, Mass.
13. Mangelsdorf, P. C., Roberts, L.M. & Rogers, J.S. (1981). The probable origin of annual teosintes. Bussey Inst., Harvard Univ. Publ. 10, 1- 69.
14. México, D.F. (1994). Maize seed industries revisited: emerging roles of the public and private sectors. World Maize Facts and Trends1993/94. CIMMYT.
15. Mink, S. D. & Dorosh, P.A. (1987). An overview of corn production. In: The Corn Economy of Indonesia. Cornell University Press, London.
16. Poehlman, J.M. (1959). Breeding Field Crops. Holt, New York, USA.
17. Purseglove, J.W. (1972). Tropical Crops: Monocotyledons 1. Longman Group Limited., London.
18. Radu, A, Urechean, V., Naidin, C. & Motorga, V. (1997). The theoretical significance of a mutant in the phylogeny of the species Zea mays L. Maize Newsletter 71, 77-78.
19. Rayor, G.S., Ogden, E.C. & Hayes, J.V. (1972). Dispersion and deposition of corn pollen from experimental sources. Agronomy Journal 64, 420-427.
20. Sears, M.K., Stanley-Horn, D.E. & Matilla, H.R. (2000). Ecological impact of Bt corn pollen on Monarch butterfly in Ontario. Canadian Food Inspection Agency (http://www.cfia-acia.agr.ca/english/ plaveg/pbo/btmone.shtml)
21. Sharma, A.B. (1998). Experts for conservation of wild crop varieties. The Financial Express. Indian Express Group.
22. Stoskopf, N.C. (1985). Cereal Grain Crops. Reston, Virginia: Reston Publishing Company, Inc., Prentice-Hall Company.
23. Watson, L. & Dallwitz, M.J. (1992). Grass Genera of the World: Descriptions, Illustrations, Identification, and Information Retrieval; including Synonyms, Morphology, Anatomy, Physiology, Phytochemistry, Cytology, Classification, Pathogens, World and Local Distribution, and References. Version:18th August 1999. http://biodiversity.uno.edu/delta
24. World Watch Institute (2000). Crop gene diversity declining. Trends in Plant Science 5, 7.
25. Wilkes, H.G. (1977). Hybridization of maize and teosinte, in Mexico and Guatemala and the improvement of maize. Economic Botany 31, 254-293.
LAST UPDATED: SEPTEMBER 2002

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GM Crop Database

Database Product Description

Summary of Regulatory Approvals

Introduction Expand

Summary of Introduced Genetic Elements Expand

Characteristics of Zea mays (Maize) Expand

Donor Organism Characteristics Expand

Modification Method Expand

Characteristics of the Modification Expand

Environmental Safety Considerations Expand

Food and/or Feed Safety Considerations Expand

Links to Further Information Expand

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GM Crop Database

Database Product Description

Summary of Regulatory Approvals

Introduction Expand

Summary of Introduced Genetic Elements Expand

Characteristics of Zea mays (Maize) Expand

Donor Organism Characteristics Expand

Modification Method Expand

Characteristics of the Modification Expand

Environmental Safety Considerations Expand

Food and/or Feed Safety Considerations Expand

Links to Further Information Expand

Output Options

Synopsis

Product Related Info

Biology Documents

Biology of Maize L.

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