Hybrid Seed Production Technology of Maize

تکنالوژی تولید تخم دورگه در جواری

1. By:
MOHAMMAD SAFAR ALIZADAH
NOORI

2. Scientificname:Zeamaysand
Family:Poaceae
Maize(Zeamays)isoneofthemostimportant
cerealcropintheworldgrownoveranareaof132
Mhawithaproductionof570m.t.Itisthecropwith
thehighestproductivity.
Maizeisservingasstaplefoodforvulnerable
segmentofthepopulationanditrankfirstin
importanceasfeedcropandalsoimportant
sourceofrawmaterialusedinnumerousindustrial
materials.
Introduction

3. Dent corn : It is characterized
by a depression or dent in the
crown of the seed. The starch
at the sides of the seeds is
corneous while the soft starch
extends to the narrow base or
tip
Flint corn: The seeds of flint
maize are hard and smooth
and contain little soft starch
Sweet corn: Contain is
sweetish starch and is
characterize by a translucent,
horneyappearance when
immature, and a wrinkled
condition when dry.
Classification maize kernels

4. Flourcorn:Floursoftmaizeaskernels,whichare
composeentirelyofsoftstarch
Popcorn:Thegrainsunusuallysmallpointedand
containanevenhigherpercentofhardstarchthanflint
maize
Podmaize:Itisanunusualtypeofmaizeeachkernel
ofwhichenclosedwithinthelemmaandpaleawhichare
welldevelop
Waxymaize:Waxymaizeissonamedbecauseofthe
somewhatwaxyappearanceofthekernels

5. Floral biology
The monoecious corn
plant has female flowers
that develop on the side of
the plant and emerge from
the leaf node.
The inflorescence is
unisexual and monoecious.
Staminate
inflorescenceis
terminal and known as
tassel and pistillateis
axillary and called as cob

6. Anthesis and Pollination
Maize is an example for protandry.
Pollen shedding begins 1-3days before the silks
emerge from the cob.
It is estimated that a normal tassel produces
2,50,00,000 pollen grains.
Pollen is viable for 12-18 hours. Silk remains receptive
for8-10days.
Anthesis continues up to 2weeks

7. b.Open pollinated varieties
c.Synthetics
d.Composites

8. Hybrid seed production
Hybrid seed of maize may generally be produced from following
different cross combinations
Single cross hybrid: (AXB)
e.g. DMH-2(CI-4 X KDMI-10)
NAH-2049(147-F2#89 X MAI-105)
(Nithyashree)
Double cross: (AXB) X (CXD)
e.g. Deccan (CM 104 x CM 105) x (CM 202 x CM 201)
Ganga-1 (CM 101 x CM 102) x (CM 200 x CM 202)
Three way cross: (AXB) X C
e.g. Ganga -5 (CM 202 x CM 111) x CM 500
Double top cross: (AXB) X Composite
e.g. Ganga safed, Histarch, Ganga 4.

9. Factors affecting hybrid maize seed
production
•Planting ratio
•Non-synchronization of flowering
•Genetic drift
•Detasseling
•Mechanical admixtures
•Rouging
•Physiological maturity of the crop
•Harvest seed crop
•Post harvest operation

10. Plantingratio:
Maizehybridsvaryconsiderablyinrespectofplantheight,Panicle
size,theamountofpollenproducedanddurationofpollen
availability.
Single cross hybrid : 4:2
Double cross : 6:2
Three way cross: 6:2
Non-synchronizationofflowering:
Goodseedsetinseedparentcanbeachievedbychronological
adjustmentofpollensheddingandsilkingrespectively.
Prolongationofeffectivefloweringperiod,plantingdesign,efficient
alterationofrowsplantingratio,staggeredplantingaresomeof
measureswhichareeffectivelyusedtoensuremaximum
synchronizationandgoodseedset.

11. Geneticdrift:
Itisrecognisedasaimportantfactoraffecting
qualityofseed.
Thedangerofgeneticchangeinrespectofcross
pollinatedcropslikemaizeisprominent.
Detasselling:Removalofmaleinflorescencefrom
themonoeciouscrop.
Thetimetakenforsheddingofpollenfromthetassel
in1-2daysafteremergence.Hencethetasselshould
beremovedbeforethesheddingofpollen.

13. Precautions to be taken while detasseling
 Hold the stem below the boot leaf in left hand and the base of
the tassel in right hand and pull it in a single pull.
 No part should be left on the plant as it causes
contamination.
 It should be uniform process done daily in the morning in a
particular direction.
 Donotbreak the top leaves as the field may be reduced due
to the earning of source material to accumulate in sink (seed) as
removal of one leaf course 1.5% loss 2 leaves 5.9% loss and three
leaves 14% loss in yield.
Detasselonly after the entire tassel has come out and immature
detasselingmay lead to reduced yield and contamination.
Mark the male rows with marker to avoid mistake in detasseling.
Look out for shedders (shedding tassel) in female rows as they may
cause contamination.

14. Afterpullingoutthetasseldropitthereitselfandburiedinsoil.
Otherwiselateemergingpollenfromdetasseledtasselmaycause
contamination.
Donotcarrythetasselthroughthefieldasanyfallofpollenmayleadto
contamination.
Donotpractice,improper,immatureandincompletedetasseling.
Improperdetasseling:aportionofthetasselisremainingintheplant
whiledetasseling.
Immaturedetasseling:carryingoutdetasselingworkwhenthetasselis
withintheleaves.
Incompletedetasseling:thetasselisremaininginlowerorunseenor
unaccountedinwithinthewholeofleaves.
Sheddingtassel:eitherfullorpartoftasselremaininfemalelineafter
detasselingandsheddingpollenwhichmaycontaminatethegenetic
purityofthecrop.
Contd…..

15. Mechanicaladmixtures:Thesecanbeavoidedtaking
dueprecautionatharvesting,seedsetting,baggingand
storingoperationsetc.
Rouging:Basedondistinctanddiagnosticcharacters
furnishedbythebreeder,rouginghastobeperformed
inseedlingstagefloweringstageandatthetimeof
harvesting(PlantandEarCharacters).
Physiologicalmaturityofthecrop:Thecropshouldbe
harvestedatproperstageofmaturitytominimize
qualitative&quantitativelosses.
Thesymptomsofphysiologicalmaturityarethe
degeneration,formationofdunkenlayer,moisture
contentofseed35%andcobsheathturnstrawyellow
colour.

16. Harvestseedcrop:theseedcropshouldbeharvested
whenmoisturecontentfallsto20-25%andharvestthe
malerowfirstandremovefromthefieldandthen
harvestthefemalerows.
Cobssorting:Removesheathandcheckforkernelcolour,
shankcolour,diseasecobs,kernelarrangementetc.
Shelling:moisturecontent15%andmechanicalcob
shellersandalsomanualrubbingagainststoneareused.
Impropershellingleadsto48%damagetokernel,
growthofstoragefungiandalsopericarpdamage,to
identifythepericarpdamageacrackonthepericarpand
alsobyferrichloridetestorTztest.

17. Seed production technology

18. Maize is grown in wide range of climatic conditions.
About 85% of the total acreage under maize is grown during
monsoon because of the fact that the crop stops growing if the
night temperature falls below 15.6
0
C or 60
0
F.
Maize crop needs more than 50% of its total water
requirements in about 30 to 35 days after tasseling and
inadequate soil moisture at seed filling stage results in a poor
yield of shriveled seeds.
Maize needs bright sunny days for its accelerated
photosynthetic activity and rapid growth of plants.
Prolonged cloudy period is harmful for the crop but an
intermittent sunlight and cloud of rain is the most ideal for its
growth.
Climate

19. Deep fertile soils rich in organic matter
well-drained soils are the most preferred
ones however maize can be grown on
variety of soils.
Soil should be medium textured with good
water holding capacity.
The pH should be between 6.5 to 7.
Soil

20. Seed source
Certifiedorfoundationseeds
aretobeprocuredfromthe
approvedcertifiedagencies

21. A plant population density of 50-55 thousands/ha is
ideal to attain maximum yield.
Hybrids: Female 10kg/ha
Male 4 kg/ha
Spacing : 60 -75cm row spacing and plant to
plant 25 -30cm.
Seed rate and Spacing

22. FYM / compost: 8-10 t /ha
NPK: 200:100:100kg /ha
Micronutrients : If deficiency is
found, apply 20 kg of zinc sulphate /
ha , boron @ 5kg /ha and Fe @12.5
kg/ha
Manures, Fertilizers and Micro
nutrients

23. Table 1: Plant height, number of days taken for 50% flowering and number of barren plants
(without cob) as influenced by spacing and fertilizer levels in African tall fodder maize.
Treatments Plantheight(cm)No.daystakenfor
50%flowering
No.barren
plants
Seed yield
(q/ha)
Spacings(cm)
S
1:45X30 208.63 63.11 15 25.35
S
2:45X45 208.101 62.22 8.50 28.93
S
3:60X30 206.97 62.77 1.44 39.48
S
4:60X45 214.52 62.25 0.22 47.55
S
5:75X30 209.93 62.77 0.22 51.67
S
6:75X45 210.28 62.55 0.00 53.27
SEm 3.91 0.30 0.28 0.19
CDat5% NS NS 0.79 0.62
Fertilizerlevels
F
1:100:50:25 202.74 64.11 4.83 39.38
F
2:150:75:50 208.90 62.50 4.11 41.22
F
3:200:100:75 215.04 61.38 3.77 42.55
SEm 2.75 0.21 0.20 0.13
CDat5% 7.66 0.59 0.56 0.37
Channakeshava B.C (1998)

24. Sowing depth (3-5cm) must be uniform to get a
uniform emergence.
The planting may be done as follows
1.Planting on the ridge
2.Planting in furrows
3.Planting on flat bed with no earthingup
4.Planting on flat bed.
Earthing up after 40-45 days of days of planting
Methods of planting and Earthingup

25. Isolation Distance
Field standards for isolation
Samekernelcolour 400m
Differentkernelcolour 600m
Sameinbrednotconfirmingtovarietalpurity 400m
ForFoundationsinglecrossesandhybridofcertifiedclass
Particulars
Foundation
seed (m)
Certified
seed (m)
Samekernelcolour 400 200
Differentkernelcolour 600 300
Fieldofsinglecrossnotconfirmingtovarietalpurity 400 200
Singlecrosswithsamemaleparentconfirmingto
varietalpurity
5 5
Singlecrosswithothermaleparentnotconfirmingto
varietalpurity
400 200

26. Isolation distance depends on seed yield of the lines
and size of the plot.
The required minimum isolation distance is 200 m in
certified seed production from the contaminant source.
Four pollen parent border rows in the field is to be
inspected four ha or less in size.
The isolation distance may be decreased by 5 m for
each increment in 2 ha in size of the plot to a maximum
of 16 ha.
Here the isolation distance may be further decreased by
12.5 m for each additional border rows to a maximum of
16 pollen parent border rows.
Isolation distance

27. Bordersrowsmustbeplantedintheseedfieldoradjacenttoit,but
innocaseseparatedbymorethanfivemetersfromthefield.
Bordersrowsmustbeplantedallalongandoppositetothe
contaminatingmaize.
Thereshouldbeareasonablestandofborderrow,i.e.,theremust
notbegapesintheborderrows.Borderrowsmusthavebeenplanted
usingtheseedrateandspacingadoptedfortheseedcrop.
Theareaplantedundertheborderrowsistakenintoconsideration
whilemodifyingtheisolationdistance.
Border rows

28. Contd..
naturalbarrierssuchastallthicktrees,buildings…etcbetweenin
theseedandcontaminatingfieldsshallnotbeasubstitutetoborder
rows.
Borderrowsmustbeplantedwithseedusedforplantingmalerows
intheseedfield.Seedsavedfrommalerowsoftheprevious
productionofthesamecrosscannotbeusedforplantingofborder
orforplantingwithisolationdistance.

29. Itistheprocessofremovalofvoluntary
plants,off-types,othercropplants,
pollenshedders,andobjectionable
weedplantsfromtheseedfieldbefore
eitherofthecropscomestoflowering.
Rouging:

30. Firstinspection:Thefieldshouldbeinspectedtoverifythatitis
properlyisolatedandfreeofvolunteerplants.
Secondinspection:Duringthevegetativegrowthphase.Isolation
shouldbechecked,alongwiththepresenceofdisease,insect
pests,orweedinfestations.Atthisstage,off-typeanddisease
plantsmayberouged.
Thirdinspection:madejustpriortoandduringflowering.
Atthistimethemaizeseedfieldismostsusceptibletogenetic
contaminationfromwindblownpollencomingfromoff-typeplants
withinthefieldorothermaizevarietiesinsurroundingfields.
Plantsthatareoff-typeordiseased,alongwithharmfulweeds,
mustberemovedatthistime.
Fourthinspection:Apre-harvestorharvestinspectionmaybe
conductedasthecropreachesmaturityandtheseedhaslosta
significantportionofitsmoisturecontent.
Field Inspections

31. Ithasbeenestimatedthatthemaizecroprequiresabout
50percentofitstotalwaterrequirementinashortperiod
of30-35daysaftertasselling.
Themostcriticalstageofirrigationduringcropgrowthis
duringfloweringandpost-floweringparticularlyduring
thegrain-fillingperiod.
Twotothreeweedingmaybenecessary,followingwhichthe
cropiseartheduptoprovideforbetterstandability.
Noweedingisrequiredafterearthingup.Effectiveweed
controlcanbeobtainedbysprayingSimazineorAtrazine(@1-
1.25kg/haof50%W.P.)beforethecropgerminates.
Irrigation
Weeding:

32. Brownstripedownymildew,
Polysorarust,
Tropicalrust,
Blackkernelrot,
MaizemosaicvirusI(MMV),
Turcicumleafblight,
Commonsmutand
Headsmut.
Shootflyandcobboreraretheimportantinsects.
Controlmeasures:SprayMancozeb2.5g/litorDithaneM-45spray
canbetaken(0.4%)assoonasfirstsymptomsareobservedanditcan
berepeatedat10daysintervaltillflowering.
HybridslikeDeccan,Ganga-5,DeccanHybridMakka-103andDHM-
1whichareresistanttorotdiseasetominimizethediseaseintensity
Pests and Diseases

33. Harvesting:Harvestwhenthehuskcompletelyturnsinto
strawcolour.
Methodsofharvesting:Malelinesareharvestedfirst
followedbyfemalelines.
Threshing:Dehusking-Thehusksareremovedmanually,
Cobsorting-Removenonfilled,diseasedcobsandcobs
havingkernelcolourvariation.
Shelling:Thecobsareshelledeithermechanicallyor
manuallyat15-18%moisturecontent.
Drying:Seedsaredriedto12%moisturecontent.
Grading:Gradetheseedsusing18/64"(7.28mm)sieve.
Seedtreatment:Treattheseedseitherwithcaptanor
thiram75%W.P.@70g/100kg.
2.5to3.6tonnes/ha

34. Seedsstoredinhigh
densitypolythenebag
(700gauge)andpoly
linedgunnybagwith
reducedmoistureof8
percentretainedseed
qualityparametersupto
15monthscomparedto
seedsstoredinclothbag
andgunnybag.
Storage

35. Field standards
Particulars FS CS
Off types 0.2 0.5
Shedding tassel0.5 1.0 (when receptive silk is 5% or more)
Seed standards for hybrids:
Parameters FoundationseedCertifiedseed
Physicalpurity(%)(min) 98 98
Inertmatter(%)(max) 2 2
Othercropseed(max) 5 kg
-1
10 kg
-1
ODVseeds(max) 5 kg
-1
10 kg
-1
Germination%(min) 80 90
Moisturecontent(%)(max)
a.Moisturepervious 12 12
b.Moisturevapourproof 8 8

36. Requirements
Substrata Between paper
Temperature 20-30
o
c
First count 4
Final count 7
Moisture determination
Temperature
By oven method
130
0
Drying time 4 hrs
Grinding Fine grinding
Standards for Germination test