HISTORY, DISCRIPTION, CLASSIFICATION, ORIGIN AND PHYLOGENETIC RELATIONSHIP GENOME STATUS IN CULTIVATED AND ALIEN SPECIES OF MAIZE.

1. Welcom

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Presented byPresented by
PAWAR VINOD SHRIPATIPAWAR VINOD SHRIPATI
Reg.No.2017/07Reg.No.2017/07
PRESENTATION ON
..
HISTORY, DISCRIPTION, CLASSIFICATION, ORIGIN ANDHISTORY, DISCRIPTION, CLASSIFICATION, ORIGIN AND
PHYLOGENETIC RELATIONSHIP GENOME STATUS INPHYLOGENETIC RELATIONSHIP GENOME STATUS IN
CULTIVATED AND ALIEN SPECIES OF MAIZE.CULTIVATED AND ALIEN SPECIES OF MAIZE.

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History
Guila Naquitz Cave in Oaxaca, Mexico is the
site of early domestication of several food crops,
including teosinte (an ancestor of maize)
Cultivation of maize in an
illustration from the
16th c. Florentine Codex
Maize domesticated in the Tehuacan Valley of Mexico.
21st
century has modified this view somewhat; scholars now indicate Balsas River
Valley of south-central Mexico as the centre of domestication.
2002 study by Matsuoka et al. all maize arose from a single domestication in the
southern Mexico about 9000 years ago.
After arrival of Europeans in 1942, Spanish settlers consumed maize and explorers
and traders carried it back to Europe and introduced it to other countries.
Maize spread to the rest of the world because of its ability to grow in diverse climates.
16th
century maize introduced in India by portuges.

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DISCRIPTION
Height: Maize plant is often 3 -5 m in height.
Stem: is commonly composed of 20 internodes of 18 cm (7.1 in)
length.
Leaf: which grown from each node, generally 9 cm in width and
120 cm in length.
Mature in 60 to 330 days
Ears: develop above a few of the leaves in the midsection of the
plant, between the stem and leaf sheath, elongating by around 3 mm
per day, to a length of 18 cm.
It is a female inflorescences, tightly involved by several layers of ear
leaves commonly called husks.
Tassel: the apex of the stem ends in the tassel, an inflorescence of
male flowers.
WC Galinat

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Classification
Flint corn : Zea mays induratas
Dent corn : Zea mays indentata
Pop corn : Zea mays aveta
Sweet corn: Zea mays saccharata
Flour corn: Zea mays amylaceae
Pod corn : Zea mays tunicata
Waxy corn: Zea mays cerabina

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Origin and Evolution of Maize
Place of origin : Mexico
Origin of cultivated maize : Teosinte
Another wild relative is Tripsacum (gamma grass)
Three views or hypothesis about origin :
1.Tripartial hypothesis
2. From Teosinte it arose.
3. Recombination hypothesis

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plantsciences.ucdavis.edu
http://hila.webcentre.ca/research/teosinte/
http://teosinte.wisc.edu/images.html
Teosinte hypothesis
Ancient people cultivated teosinte because it
provided a useful food source
During cultivation, mutations that improved
teosinte’s usefulness to humans arose and were
selected.
Over the course of time, humans selected
additional major mutations plus many minor
ones.
One form of Teosinte (Zea mays ssp
parviglumis) shares close genetic relationship
with maize (isozyme and microsatelite evidence)
Cytological evidence:
same chromosome numbers, complete
chromosome paring, full fertility (Emerson &
Beadle 1932) . Chromosome arm length,
centromere position, sizes in annual teosintes are
identical to those in maize Longley 1941).
Longley (1941) & Kato (1976) later suggested that
from all teosintes, mexican were the more similar
As stated by Beadle (1939)

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Maize genome
•The maize genome is a medium sized plant genome
•Genome size : 2500 Mb
•US based researcher who decoded the genome of an B37 inbred line
of maize
www. PGSB. website

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Breeding objectives
1. Yield
2. Breeding for pest and disease resistance : shoot fly, stem borer are the major
pests. Mexican varieties are resistant.
Downy mildews, leaf blight and helminthosporiun are major diseases.
Taiwan line are resistant to downey mildew.
3. Breeding for high protein : composed of two fraction
a. protein in endosperm (80%) known as Zein which is nutritionally not balanced
since it is lesser in lysine and tryptophane.
b. protein in germ (embryo) 20%
4. Breeding for increased oil content. : 12 – 15 % in germ
5. Alternate sources of cytoplasm : CMS-T suceptible to helminthosporiun,C and
S Resistant
6. High yielding baby corn : Zea mays var sachharata, sweet corn. The cobs can
harvested 45 days after sowing. CoBc 1 is latest variety of baby corn.

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Breeding methods:
1. Introduction : Mexican line were first introduced during 16th
century by portugeese
2. Mass selection: Prior to 1945 mass selection was the only method used for maize
improvement. By adopting mass selection technique it is possible to get yield increase by
19 % per cycle.
3. Ear to row selection: first proposed by Hopkins for improving oil and protein content of
maize. This method involved selection of number of phonotypical desirable ears harvested
separately on single plant basis and keeping part of the seeds and remaining sown in rows.
based on the performing rows during next season the reserve seeds are sown. This method
suitable for characters having high heritability like oil content and protein content. But it
not helpful to get increased yield.
4. Modified ear to row : proposed by Lonquist.
5. Hybridization and selection:
6. Heterosis breeding: instead of using CGMS lines, detasseling the female inbred line is
followed in India. Crossing the inbred of indigenous X exotic origin resulted in release of
best hybrids. Indian x Indian : 24-43% yield increase Indian X US - dent : 58%, Indian
dent X Caribbean Flint : 47-54%
7. Population improvement: recurrent selection technique was initiated by Dhawan in
1963. kisan, jawahar, sona

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1. Single cross hybrids: (A X B) Eg. CoH1, CoH2
2. Three way cross hybrids : [(A x B) x C] Eg. Ganga-5
3. Double cross hybrids: [(A x B)x (C x D)] Eg. CoH 3
4. Top cross hybrid : one of the parents is an open-pollinated variety and other is
single cross hybrid or an inbred line. Eg. Ganga Safed 2, Ganga 4.

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National and International Institutes:
Institute Germplasm collection
1. Directorates/project directorates of Maize, New Delhi. 2500 accessions
2. CIMMYT, Mexico 2700
3. NBPGR, New Delhi. 6912
Mutants
1.Opaque-2 : High lysine and tryptophane contents
2.Floury-2 : Increased protein,lysine,tryptophane and methionine content
3.Illinois High Protein: High protein
Transgene
Cry gene incorporated resistant to corn borerr.

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