Maize: Multipurpose Edible Crop with Multi-nutrients

Maize is the leading grain and multipurpose edible crop in the world. It constitutes staple foods for large groups of people in Latin America, Africa, and Asia. Maize production has increased the most because of certain aspects. It has greater adaptation to different ecological systems. There is strong demand of maize for bioethanol, animal feed, production of sweeteners and other non-food industrial products. Its production is more than one billion tons. It is also known as corn. It is cereal plant of Gramineae family of grass. The main structures of the plant are the coleoptile, leaves, stalk, roots, ear and tassel.

Scientific Classification

• Kingdom: Plantae
• Clade: Tracheophytes
• Clade: Angiosperms
• Clade: Monocots
• Clade: Commelinids
• Order: Poales
• Family: Poaceae
• Subfamily: Panicoideae
• Genus: Zea
• Species: Z. mays

Types of Maize

Dent maize is the primary type of maize grown in the US Corn Belt as well as in Europe, South Africa, and China. Dent varieties have been adapted through hybridization and selection to provide a wide range of agronomic and kernel characteristics.

Flint maize is genetically different in ancestry from dent maize and is characterized by hard, round kernels. Flint maize endosperms consist predominantly of the hard or vitreous endosperms. The agronomic characteristics of flint maize differ from dent maize, primarily due to the unique needs of the historical growing regions.

Popcorn is flint-type maize that has been genetically selected for its ability to expand or ‘pop’ when heated. Popping occurs when the kernels are rapidly heated to ∼240 °C. As the protein matrix cools, it becomes rigid.

Sweetcorn is dent-type maize that is harvested while still immature for canning, freezing, and direct consumption as a vegetable. Sweetcorn hybrids contain a gene that retards the conversion of glucose to starch in the endosperm.

Cultivation – Life Cycle of Maize

Growth and development of the maize plant are complex processes. During the life cycle of the plant, many of the growth stages overlap. One part of the plant may be developing and another part may be dying. Growth of a maize plant is defined as the accumulation of dry matter. Development is concerned with the plant’s progression from being vegetative (i.e. growing) to reproductive.

Factors affecting reproductive development

Factor	Affect
Moisture stress	Moisture stress at flowering reduces the number of kernels per plant and grain yield. When moisture stress coincides with flowering than at other growth stages, grain yield is reduced two or three-fold more. It will reduce yields by 6% to 8% a day. If it is combined with nutrient stress, yields can be reduced by 13% a day.
Temperature	When temperature reaches 38°C or higher, it is difficult to maintain adequate water movement through the plant, even under irrigation. Hot and dry weather conditions interfere with pollination than wet weather. Pollen grains contain about 80% water when first shed. These pollen grains die when the water content decreases to about 40%.
Competition from other plant parts	During flowering, ear growth is susceptible to competition from other plant parts. The ear is competing for the limited supply of assimilates from photosynthesis. The result can be low grain number per ear and occasionally barren ears.
Assimilate supply	Lack of sugars and proteins may result from lack of water and nutrient deficiencies. It would reduce photosynthesis due to very cloudy weather or damage leaves from insects or disease.

Difference between Maize and Corn

The word “corn” has various meanings regarding different geographical regions. In Scotland and Ireland, it relates to oats. In the Bible, corn is considered as wheat and barley. In the USA and Canada, corn and maize are same as they are meant for the plant that produces kernels used for cooking.  However, the term corn is preferred over maize for food products that are made from it, such as corn flour, corn starch, cornmeal, etc. Corn is used as general term and Maize is used in specific meaning.

Maize is used to refer the food crop, especially prior to harvesting. A farmer is growing maize and will eventually harvest maize to sell on the market as corn. Maize can refer to what is grown in the field, whereas corn refers to the harvested product or the food at the market. All maize is corn, but not all corn is maize. 

Diseases of Maize

• Nitrogen Deficiency:  The typical symptom of nitrogen deficiency is the plant turns pale green. This pattern starts from leaf end to leaf collar, and symptom begins from lower to upper leaves.
• Phosphorous Deficiency: The deficient plants are dark green and lower leaves show reddish-purple discoloration.
• Potassium Deficiency: Margins of leaves turn yellow and brown which appears like firing or drying. The symptoms progress from lower leaves to upper leaves.
• Sulfur Deficiency: Symptom appears on younger leaves where we will see yellow color striping (interveinal chlorosis).
• Zinc Deficiency: Upper leaves shows broad bands of yellow coloration and later turn pale brown or gray necrosis(dead-spots). The symptom first appears in the middle of leaves and progresses outward.

Products and Uses

Food and nutrition

 Corn is high in dietary fibre and rich in antioxidants. Corn flour is gluten-free and cannot be used alone to make rising breads. It is widely used in Latin American cuisine to make masa, a kind of dough used in such staple foods as tortillas, arepas, and tamales. Sweet corn is boiled or roasted on the cob, creamed, converted into hominy or meal. It is also cooked in corn puddings, mush, polenta, griddle cakes, cornbread, and scrapple. It is also used for popcorn, confections, and various manufactured breakfast cereal preparations.

Corn is also fermented into a number of alcoholic beverages, especially bourbon and other corn whiskeys. Corn oil is used primarily for food. It is favored as a salad oil and frying oil because it contains little cholesterol. Corn oil can be converted into margarine by hydrogenation, a process in which the oil is combined with hydrogen at high temperature and pressure in the presence of a catalyst.

Biofuel

Corn is also used to produce ethanol (ethyl alcohol) that is a first-generation liquid biofuel. Corn ethanol is typically blended with gasoline to produce “gasohol,” an automotive fuel that is 10 percent ethanol. Although corn-based biofuels were initially touted as environmentally friendly alternatives to petroleum. Their production diverts arable land and feedstock from the human food chain, sparking a “food versus fuel” debate. In addition, crops grown for biofuel can compete for the world’s natural habitats. It emphasises on ethanol derived from corn has shifted grasslands and brushlands to corn monocultures in some places, impacting biodiversity. Beyond land-use changes, the process of growing corn to produce ethanol consumes fossil fuels in farming equipment, fertilizer manufacturing, corn transportation, and ethanol distillation.

Conclusion

Maize is a healthy food due to the presence of nutrients and phytochemicals. These nutrients play very crucial role in preventing from chronic diseases. Based on the health benefits of maize, it can be recommended and made a part of our daily diet. Maize stands as a multipurpose crop serving nutritional, medical, pharmaceutical, industrial and other economic uses. Hence, more land area is advice to be put into maize cultivation as the demand for corn, its by-product and corn-related products will continue to increase as human population increases, and as science further explores the crop for more beneficial uses.

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