Maize botany.pdf

Agriculture maize botnay

1. Maize
KumariShikha
Assistant Professor
DDU Gorakhpur University

2. Maize (Corn) -Zeamays(2n=20)
•Maize plant belongs to the tribe Maydeaeof the grass family Poaceae.
•Zea(zela) word was derived from an old Greek name which refer to food
grass.
•It is cultivated globally being the third most important cereal crops
worldwide after rice and wheat.
•Corn has a life cycle of 120 to 150 days.
•Possess protein-Zein
•Maize deficient in lysine and tryptophan
•Opaque-2 gene (QPM)-rich in lysine and tryptophan
•People dependent on only maize as staple crop –suffer from Pellagra (due
to deficiency of niacin)

3. Taxonomy
Kingdom: Plantae
Division: Magnoliophyta(Flowering plants)
Class: Liliopsida(Monocotyledons)
Order: Poales
Family: Poaceae
Genus: Zea
Species: mays

4. Centre of origin
•Mexico and Central America

6. Evolution of maize:
•Probable ancestor of maize: Zeamexicana
•Three general theories regarding the origin of maize:
i.Some authors reviewed that it originated from pod-corn,Zeamays var.
tunicata.
ii.Maize originated from teosinte,Euchlaenamexicana, which is a wild
grass native to Guatemala and Mexico, by direct selection, mutations or
by the hybridization of Euchlaenawith a grass which is presently
unknown.
iii.Zea,Euchlaenaand Tripsacumall three have been descended from a
common ancestor through divergent evolution but the ancestor may
have lost.

7. Growth stages of corn
Growth stages of corn
1.Vegetativegrowthstage 2.Reproductivegrowthstages
Seedling Emergence, Leaf and Tasseling stage
Silking,blister,milk,doughandmaturitystage

8. Botanical description

9. Habitat
•Tropical and sub-tropical

10. Habit
•Herbaceous annual, tall and C
4plant with determinate growth.
•It is protoandrouscrop.

11. Stem
•Stem:Stout, solid with distinct nodes and internodes. It consist of
sheath surrounding the stalk.

12. Roots
•Itconsistoffibrousrootsystem.
•Bracerootsareformedatthebottomofthestalk
andprovidesupporttotheplantandscavengetop
levelsofsoilformoistureandnutrients.
•Seminalrootsornodalrootsoriginatefromscutellar
nodeandsustainseedlingdevelopmentbyvirtue
waterintake.

13. Leaves
•Leavesarebroadandasingleleafat
eachnode.
•Leavesarearrangedintwoverticalrows
ontheoppositesidesofanaxis
(distichous).
•Long,large,alternatewithparallel
venation.

14. Inflorescence
•UnisexualorMonoecious-Maleand
femaleinflorescencelocatedatdifferent
partsoftheplant.
•Maleinflorescenceisterminalstaminate
compoundracemecalledtassel.
•Femaleinflorescenceisauxiliarypistillate
spadixcalledear.
•Maizepollendispersionbywind.

15. Tassel
•Malereproductivepartofthecornplantalsoknownasandroecium
•StalkAlsoknownasfilament,thepartofthestamentheantherdevelop.
•Antheristheterminalpartofastamenwherethepollensareproduced.
•Maleinflorescenceconsistsofmanyspikelets.
•Thespikeletsoccurinpairs—theloweroneissessileandtheupperoneisstalked.
•Eachspikeletconsistoftwofloret.Theyhavefourglumes.Thefirstandthesecondglumes
locatedatthebasearesterileandthethirdone,calledfloweringglumeandthelastone,the
two-nervedpalea,encloseaflower.Flowersareobviouslymonoecious.Perianthis
representedbyapairoffleshyscale-likebodiescalledlodicules.
•Androeciumiscomposedofthreefreestamenswithlongprominentlinearanthers

16. Ear
•Theearisthefemalereproductivepartofacornplant.
•Earsdevelopfrom"shanks,"whicharestalk-likestructures
thatgrowfromtheplant'sleafnodes.
•Acornplantmayproducemanyears,buttheuppermost
earwillgrowtobethelargest.
•Eariscoveredbytheleaflikestructurescalledhusks
(bracts)
•Theearconsistsofacob,eggsthateventuallydevelopinto
kernelsandsilks.

17. Fruit
•Caryopsis (79% starch and 9% protein)

18. Economic importance
•Maizeisnotonlyanimportantfoodcropforhuman
consumption,butalsoabasicelementofanimalfeed
andrawmaterialformanufacturingofmany
industrialproducts.
•Itisalsousedintheproductionofbiofuel,Gluten
starch,ethanol,refinedcornoil,sorbitol,
maltodextrins,cakemixes,candies,beer,carbonated
beverages,paperadhesivesandcosmeticsetc.
Corn starch
Corn Beer
Corn Oil
Bioplastic
Yoghurt
Spark plugs
Rubber tyre

19. Selfing technique
•Maize,beingacross-pollinatedcrop,variousreproductiveisolation
methodsareusedbyplantbreedersandbyseedproducertoproduce
geneticallypureseed.
•Topportionofearisremovedbeforeemergenceofsilkandbaggedwith
butterpaperbag.Whensilkarisefrombaggedear,tasselofthesameplant
iscoveredwithtasselpaperintheeveninghours.Polleniscollectedinthe
bagbytappingitgentlythendustedoversilkofthesameplanttoensure
selfing.Plantistaggedwithdateofselfing.

20. Crossing technique
•Topportionoftheearisremovedbeforeemergenceofsilkand
coveredwithbutterpaperbag.Whensilkarisefrombaggedear,
tasselofthedifferentplantfromwhichpollenistobetaken,is
coveredwithtasselbagintheeveninghours.Polleniscollectedinthe
bagbytappingitgentlythendustedoversilkofthebaggedearto
ensurecrosspollination.Plantislabelledwithdateofcrossingand
parentnames.

21. 1. Cut the ear before emergence of silk

22. 2. Cover ear with silk bag

23. 3. Bagging of tassel to collect pollen

24. 4. Collect pollen next morning hours

25. 5. Dust the pollen over silk

26. 7. Bagging and tagging of pollinated ear