Maize botany.pdf
- 1. Maize Kumari Shikha Assistant Professor DDU Gorakhpur University
- 2. Maize (Corn) - Zea mays (2n=20) • Maize plant belongs to the tribe Maydeae of 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: Zea mexicana • Three general theories regarding the origin of maize: i. Some authors reviewed that it originated from pod-corn, Zea mays var. tunicata. ii. Maize originated from teosinte, Euchlaena mexicana, which is a wild grass native to Guatemala and Mexico, by direct selection, mutations or by the hybridization of Euchlaena with a grass which is presently unknown. iii. Zea, Euchlaena and Tripsacum all 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. Vegetative growth stage 2. Reproductive growth stages Seedling Emergence, Leaf and Tasseling stage Silking, blister, milk, dough and maturity stage
- 9. Habitat • Tropical and sub-tropical
- 10. Habit • Herbaceous annual, tall and C4 plant with determinate growth. • It is protoandrous crop.
- 11. Stem • Stem: Stout, solid with distinct nodes and internodes. It consist of sheath surrounding the stalk.
- 12. Roots • It consist of fibrous root system. • Brace roots are formed at the bottom of the stalk and provide support to the plant and scavenge top levels of soil for moisture and nutrients. • Seminal roots or nodal roots originate from scutellar node and sustain seedling development by virtue water intake.
- 13. Leaves • Leaves are broad and a single leaf at each node. • Leaves are arranged in two vertical rows on the opposite sides of an axis (distichous). • Long, large, alternate with parallel venation.
- 14. Inflorescence • Unisexual or Monoecious- Male and female inflorescence located at different parts of the plant. • Male inflorescence is terminal staminate compound raceme called tassel. • Female inflorescence is auxiliary pistillate spadix called ear. • Maize pollen dispersion by wind.
- 15. Tassel • Male reproductive part of the corn plant also known as androecium • Stalk Also known as filament, the part of the stamen the anther develop. • Anther is the terminal part of a stamen where the pollens are produced. • Male inflorescence consists of many spikelets. • The spikelets occur in pairs—the lower one is sessile and the upper one is stalked. • Each spikelet consist of two floret. They have four glumes. The first and the second glumes located at the base are sterile and the third one, called flowering glume and the last one, the two-nerved palea, enclose a flower. Flowers are obviously monoecious. Perianth is represented by a pair of fleshy scale-like bodies called lodicules. • Androecium is composed of three free stamens with long prominent linear anthers
- 16. Ear • The ear is the female reproductive part of a corn plant. • Ears develop from "shanks," which are stalk-like structures that grow from the plant's leaf nodes. • A corn plant may produce many ears, but the uppermost ear will grow to be the largest. • Ear is covered by the leaf like structures called husks (bracts) • The ear consists of a cob, eggs that eventually develop into kernels and silks.
- 17. Fruit • Caryopsis (79% starch and 9% protein)
- 18. Economic importance • Maize is not only an important food crop for human consumption, but also a basic element of animal feed and raw material for manufacturing of many industrial products. • It is also used in the production of biofuel, Gluten starch, ethanol, refined corn oil, sorbitol, maltodextrins, cake mixes, candies, beer, carbonated beverages, paper adhesives and cosmetics etc. Corn starch Corn Beer Corn Oil Bioplastic Yoghurt Spark plugs Rubber tyre
- 19. Selfing technique • Maize, being a cross-pollinated crop, various reproductive isolation methods are used by plant breeders and by seed producer to produce genetically pure seed. • Top portion of ear is removed before emergence of silk and bagged with butter paper bag. When silk arise from bagged ear, tassel of the same plant is covered with tassel paper in the evening hours. Pollen is collected in the bag by tapping it gently then dusted over silk of the same plant to ensure selfing. Plant is tagged with date of selfing.
- 20. Crossing technique • Top portion of the ear is removed before emergence of silk and covered with butter paper bag. When silk arise from bagged ear, tassel of the different plant from which pollen is to be taken, is covered with tassel bag in the evening hours. Pollen is collected in the bag by tapping it gently then dusted over silk of the bagged ear to ensure cross pollination. Plant is labelled with date of crossing and parent names.
- 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