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Maize Varieties and Quality Seeds
Dr. Bhagya Rani Banik
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Importance of maizeImportance of maize1.1. HIGH YIELDHIGH YIELD
2.2. Year round productionYear round production
3.3. C4 crop, the crop of global warmingC4 crop, the crop of global warming
4.4. Less disease and pestsLess disease and pests
5.5. Versatile use;Versatile use;1. Food (flour, flakes, soup)
2. Feed (poultry, dairy, fish)
3. Baby corn, green corn, pop corn
4. Starch, oil5. Fodder, fuel
6. Green manure
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Maize Area, Production and Yield in Bangladesh
0.00
500.00
1000.00
1500.00
2000.00
2500.00
1 9 8 9 - 9 0
1 9 8 9 - 9 1
1 9 9 1 - 9 2
1 9 9 1 - 9 3
1 9 9 3 - 9 4
1 9 9 3 - 9 5
1 9 9 5 - 9 6
1 9 9 5 - 9 7
1 9 9 7 - 9 8
1 9 9 7 - 9 9
1 9 9 9 - 0 0
1 9 9 9 - 0 1
2 0 0 1 - 0 2
2 0 0 1 - 0 3
2 0 0 3 - 0 4
2 0 0 4 - 0 5
2 0 0 5 - 0 6
2 0 0 6 - 0 7
2 0 0 7 - 0 8
2 0 0 8 - 0 9
2 0 0 9 - 1 0
Year
A r e a
( 0 0 0 h a ) a n d
P r o d u c t i o n
( 0 0 0 t o n )
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
Y i e l d
( t o n h a
- 1 )
Area (000 ha)
Production (000) ton
Yield (t/ha)
Fig 1. Area, production and grain yield of maize in Bangladesh (1990-2010)
Source: BBS and DAE, 2010
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Table 3. Production target in 2010, 2015, 2020, 2030 and 2050
(as far as available)
Projected population/
Demand/ Production
target of maize
Projected Year
2010 2015 2020 2030
Projected pop. (mil.) 148.0 156.7 166.9 190.6
Demand (mil. ton) 1.88 2.25 3.00 3.50
Target area (m ha) 0.20 0.30 0.35 0.40
Target avg. yield (t/ha) 6.5 7.5 8.0 8.5Prodn, target (mil. ton) 1.30 2.25 2.80 2.97
Source: BBS andMoA
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Farmers field, ComillaFarmers field, Comilla (22 May 2009)(22 May 2009)
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Reasons for popularityReasons for popularity::
1. High grain yield
2. Two cropping seasons per year
3. Flexibility in planting time4. Fits well in cropping pattern
5. Low risk of complete crop damage
6. Can be used as fresh, boiled, dried & fried
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ProblemsProblems
1. Pollination control2. Inbreeding depression
3. Maintenance of inbred lines
4. Maintenance of hybrid variety ?
5. Short viability of seed
6. Shelling
7. Drying
8. Milling9. Eating
10. Selling
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ProblemsProblems
1. Pollination control2. Inbreeding depression
3. Maintenance of inbred lines
4. Maintenance of hybrid variety ?
5. Short viability of seed
6. Shelling
7. Drying
8. Milling9. Eating
10. Selling
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VarietyVariety developmentdevelopment
1. Composite/Synthetic/OP
2. Hybrid: Single, 3-way, double cross
3. Top cross/Double top cross hybrid
4. Sweet corn
5. Pop corn
6. Baby corn (vegetable)
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Classification
�Dent maize
�Flint maize
�Sweet corn
�Flour corn
�Pop corn
�Pod maize
�Waxy maize
� Baby corn
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List of composite maize varieties developed by BARI
Variety Yield (t/ha) Year of
release
Suitable area
1. Barnali 4.0-5.0 t/ha 1986T
he crop can be cultivated all over Bangladesh
2. Shuvra 4.5-5.5 t/ha 1986 The crop can be cultivated all over Bangladesh
3.Mohar 4.5-5.6 t/ha 1986 The crop can be cultivated all over Bangladesh
4. BARIMaize 5 5.5-6.0 t/ha 1997 The crop can be cultivated all over Bangladesh
5. BARIMaize 6 5.7-6.2 t/ha 1998 The crop can be cultivated all over Bangladesh
6. BARIMaize 7 5.5-6.5 t/ha 1998 The crop can be cultivated all over Bangladesh
7. Khoibhutta 4.5-5.0 t/ha 1986 The crop can be cultivated all over Bangladesh
8. BARI Sweet corn 1 10-10.5 t/ha 2002 Homestead areas
Achievement of maize improvement at BARI
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Achievement of BARI
List of hybrid maize varieties developed during 2000-2010
Hybrid Variety Yield
(t/ha)
Maturity Year of
release
Grain colour and texture
BARI hybrid maize 1 7.5 - 8.5 140-145 2000 Orange-yellow, flint
BARI hybrid maize 2 8.0 -9.0 138-142 2002 Orange-yellow, semi-flint
BARI hybrid maize 3 9.0 -9.5 144-150 2002 Yellow, dentBARI hybrid maize 4 7.5 - 8.5 142-146 2002 Orange-yellow, flint
BARI hybrid maize 5 9.0 - 10.0 140-145 2004 Orange-yellow, flint
BARI hybrid maize 6 9.8 - 10.0 141-145 2006 Yellow, flint
BARI hybrid maize 7 10.5-11.2 141-145 2006 Yellow, flint
BARI hybrid maize 8 9.7 -11.5 142-146 2007 Yellow, dent
BARI hybrid maize 9 10.2 -12.0 145-150 2007 Orange-yellow, dent
BARI hybrid maize 10 9.0 -11.5 145-150 2008 Yellow, flint
BARI hybrid maize 11 9.5 -11.5 147-153 2008 Yellow, flint
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Dent maize
Flint maize
Flint and Dent Maize
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Dehusked Sweet CornSweet cob corn with husk
Sweet corn
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Mature pop corn Popped corn
Pop corn
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Baby corn with husk
Baby corn without husk
Baby corn to harvest
Baby Corn
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Estimation of heterosis
� Mid parent heterosis %
= F1-Mean of parents (MP)--------------------------------------X 100Mean of parents (MP)
� Heterobeltiosis %
F1-Mean of better parent (BP)
--------------------------------------X 100
Mean of better parents
� Standard heterosis %
F1-Mean of standard check
--------------------------------------X 100
Standard check
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Concept of hybrid maize
development
�
Source materials� Development and evaluation
of parent materials
� Development of hybrids
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Development and evaluation of
parent materials
� By enforced selfing followed by
selection
� Sibbing whenever necessity will
arise
� Evaluation by combining ability
test
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� Ter minology related to hybrid technology
� Inbred line : A nearly homozygous line developed by
continued inbreeding, usually self ing,accompanied by selection.
� Inbreeding : Mating between individuals related by descent or
ancestry.
� Inbreeding Depression : Loss in vigour due to inbreeding.
� Heter osis : Superiority of F1over the parents (or even
inf eriority to both the parents).
� Hybrid Vigour : Synonymous to Heter osis.
� Hybrid : Pr ogeny f r om hybridization between two or more strains.
� Hybrid variety : A hybrid variety is the F1 generation f r om a
cr oss between two diff erent strains.
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Types of hybridsTypes of hybrids
� a) Single cr oss: A single cross hybrid is the product of a cross
between two unrelated inbreds.
� Seed parent X Pollen parent
(Inbred A) (Inbred B)
�
� Single cross ( AB)
� b) Modif ied single cr oss : A modified single cross is a
cross of the type ( A x A1) X C where A and A1 are sister lines.
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� c) Three way cr oss : A Threeway cross hybrid is produced
by crossing a single cross and another unrelated inbred
� Seed parent X Pollen parent
�(Single cross
AB) (Inbred C)
�
� Threeway way cross
� ( ABC)
� d) Double cr oss : A double cross hybrid involves 4 unrelated
inbreds. At first two single crosses are produced. The two single
crosses are mated to produce the double cross.
� Seed parent X Pollen parent
� (Single cross AB) (Single cross CD)
�
� Double cross
� ( ABCD)
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� Sequential steps in hybrid seed pr oduction
� Commercial hybrid maize seed production broadly involvethe following steps :
� 1. Maintenance and breeder¶s seed production of the parental lines
� 2. Multiplication/production of breeders seed, foundation seed
certified seed
� 3. Production of hybrid seed i.e. single cross, threeway cross anddouble cross
� 4.Processing of the hybrid seed
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eren ec n ques n y r seeeren ec n ques n y r see
pr oduction of maizepr oduction of maize
Site selectionSite selection
Land typeLand typeIsolated f ield requirementIsolated f ield requirement
Table 1. Showing number of isolated plots/f ields necessary for diff erentTable 1. Showing number of isolated plots/f ields necessary for diff erent
types of conventional hybridstypes of conventional hybridsTypes of hybrid Inbred
parents
SC
parent
Hybrid Total
Single cross 2 - 1 3
Three-way cross 3 1 1 5
Double cross 4 2 1 7
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� Time of sowing� Plant population densities
� Avoiding mixtures of males and
f emales� Female : Male ratios
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IsolationIsolation
1. Isolation Distance - The greatest contamination occurs within 50 to 75 m
of the contaminating source. Minimum isolation
distances for hybrid maize as foundation and
certified seeds are 400 m and 200 m, respectively
- Certainly, the greater the distance and number of male border rows, the less chance of contaminate pollen
entering in the field.
2. Time Isolation - Using time isolation, it is best to have a minimum of
25 days to one month difference between the
planting of seed crop and potential contaminatesources. This time may slightly vary with different
varieties.
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� Techniques applied for synchr onization
of f lowering*Delayed planting
*Double planting of male rows
*Clipping or mowing - It is effectively used to save a maize
crop when inclement weather occurred after the first
parent was planted but before the second parent was
sown. It is best to mow when plants are about 25 to30cm tall, cutting away half of the plant material.
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Table 2. Showing the amount of delay based on different treatment times
Treatment Delay in flowering*
20 cm cutback to 10 cm 4 days
60 cm cutback to 30 cm 7 days
90 cm cutback to 45 cm 7 days
Proc. of the Third Ann. Seed Tech. Conf., Iowa State University, 1980.
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� Impr oving pollendistribution and seed set
� Collect pollen f r om male r ows and
hand pollinate
� Physically shake male lines.
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� Roguing
� There are three basic types of
rogues
� Volunteer corn : These are corn plants grown in the
field from previous year outside the production field but
within the isolation limit.
� Off types: Any corn plants in the seed production field
other than the designated parents.
� Plants out of place : Females in male rows and
vice versa. Some plants may be displaced during
irrigation and other cultural operation.
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� Two types of contamination can
occur in the field
� Genetic contamination - Caused by cross-
pollination with other maize plants growing in the
field or in the isolation area. It can also be causedby accidental self-pollination of female parents of
hybrids due to improper detasseling.
� Mechanical contamination - Caused by mixing
seed or transplanting of undesirable plants
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WhenWhen toto roguerogueRoguingRoguing shouldshould bebe donedone duringduring thethe followingfollowing stagesstages of of plantplant growthgrowth ::
Post emergence
: Rogue off-type plants that are often
easily identified due to their
difference in size and their position
out of the rows.
Vegetative
development
: Rogue off-type plants, which differ
from the given genotypes in respectto stalk development, plant type,
pigmentation, leaf and stem
pubescence.
Flowering : Rogue off-type plants, which differ inagronomic and morphological
characteristics, before pollen
shedding starts.
Post flowering:
Rouge off-type and diseased plants.
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� Pr ocedures for r oguing
� Select responsible people and pr ovidepr oper training on the identif ication and
removal of off types.
� Each member of the r oguing team should
have a narr ow zone to observe. One member considers a maximum of 2 r ows.
� Short r oguing in a corner of the f ield and
wo
rk thr o
ugh it slo
wly, walkingp
arallel andin the same direction down the r ows.
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� Detasseling� A detasseling team comprised of sincere, eff icient workers
should be employed for this work.
� The detasseling team has to work in the f ield everyday, rain
or shine.
� Tassel should be pulled when they are well out of the
³boot´. This of ten occurs 1-2 days af ter the tassels are f irst
visible.� If the detasseling is done before optimum stage, 1 or 2
leaves may be removed with the tassel, or the tassel may
break off and not completely removed. Removal of tassel
along with leaves may reduce the seed yield.
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� Mechanical detasseling
� Pollination� It is estimated that an average tassel may produce as
many as 25 million grains to pollinate 300-600 kernels
in any given ear. Thus for every seed to be pollinated,
at least 25,000 pollen grains are available.
� Harvesting
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Operations/ Steps Followed in Harvesting
and Post-harvest pr ocessing of Maize
Time Of Harvesting
Husking, Sorting And Harvesting method
Drying
Shelling
Cleaning
SeedTreatment
GerminationTests Weighing, Bagging, Tagging And Sewing Seed
Storage
Carry-over Seed
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HarvestHarvest -- TimingTiming
� Seed should be harvested when
physiological or functionalmaturity is attained. This generally
coincides with the maximum
accumulation of dry matter and is
know as physiological maturity.
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Indications of seed reaching maturityIndications of seed reaching maturity
Milk layer Dry husks
Black layer
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HarvestHarvest ± ± TimingTiming -- EarlyEarly
� At physiological maturity (30 ± 35%
moisture)
� Advantages
a) best seed quality
b) market seed earlier
c) land availability for subsequent crop
� Disadvantages
a) Requires mechanical drying facilities
b) Cost
c) Risk of heat damage
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HarvestHarvest ± ± TimingTiming -- LateLate
� At 12 ± 16% moisture
� Advantage - lower cost
� Disadvantage ± exposure of seed toundesireable elements such astemperature and moisture extremes,diseases, insects, birds, theft, etc.
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Male line harvest before hybrid seed harvest
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Sorting/Selection
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Drying the Seed CropDrying the Seed CropDefined ± process through which moisture is
removed from the seed until the moisture
content is low enough to permit storage of
the seed for relatively long periods of time
without deteriorationRecommended seed moisture
± Harvest = 30-35%
± Shelling = 14-16% ± Storage = 12%
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Drying the Seed CropDrying the Seed Crop
Sun drying
Usually done before shelling on a patio
with a concrete f loor or on black
plastic sheeting
Labor is required to spread and turn
cobs (or grain) to evenly expose
them to sun
Long drying time where seed may be
exposed to rain, insects, etc.