---

Maize Cultivation: One-Liners & Important Facts 🌽

📌 1. General Introduction & Botany

• Botanical Name: Zea mays.
• Family: Poaceae (also known as Gramineae).
• Chromosome Number: 2n = 20 (it is a simple diploid crop).
• Origin: Mexico or South America.
• "Queen of Cereals": Maize has the highest yield potential among all cereal crops, which is why it is crowned the "Queen of Cereal Crops".
• Plant Type: It is a C4 plant (Fun fact: the C4 cycle was originally discovered in maize and sugarcane).

🌽 2. Nutritional Value & Floral Biology

• Nutritional Content: Contains around 70% carbohydrates and about 10% protein. The specific protein found in maize is known as Zein.
• Monoecious Nature: Maize is a monoecious plant, meaning the male and female flowers are separate, but they are present on the same plant.
• Inflorescence (Flowers):
  • Male Flower: Known as the Tassel.
  • Female Flower: Known as the Silk or Cob.
• Pollination: Even though both male and female flowers are on the same plant, maize is a cross-pollinated crop. This is due to Protandry (the male flower/tassel matures earlier than the female flower), preventing self-pollination.

🌾 3. Classification of Maize (7 Sub-Species)

Maize is classified into 7 distinct sub-species based on grain size, shape, and chemical composition:

1. Flint Corn (Zea mays indurata): Cultivated mainly in India; also known as "Indian Corn".
2. Dent Corn (Zea mays indentata): The grain has a slight depression/dent. It accounts for 95% of cultivation in the USA and is also called "Field Corn".
3. Popcorn (Zea mays everta): Has a very hard seed coat and dense endosperm, allowing it to pop when heated.
4. Sweet Corn (Zea mays saccharata): Contains more sugar than starch. It must always be harvested at an immature stage to retain its sweetness.
5. Flour Corn (Zea mays amylacea): Primarily used for making maize flour.
6. Pod Corn (Zea mays tunicata): Each grain is enclosed in a husk. Currently has no major commercial use.
7. Waxy Corn (Zea mays ceratina): Features a highly waxy endosperm.

🌱 4. Genetics & Important Varieties

• QPM (Quality Protein Maize): Normal maize is deficient in the amino acid Lysine. QPM was developed to be rich in Lysine using the Opaque-2 gene.
• Important Hybrids: HQPM-1, HQPM-5, and Vivek.
• Composite Varieties: The Shaktiman series (Shaktiman-1, 2, 3, and 4) are highly popular composite varieties.
• First AICRP & Hybrid: The very first All India Coordinated Research Project (AICRP) was started on Maize in 1959. This led to the development of India's first maize hybrid, Ganga-1, in 1961, created using the double-cross hybrid technique.

🌦️ 5. Climate, Soil, & Sowing Time

• Soil: Dark loamy soil is considered excellent for maize cultivation.
• Season: Maize can be cultivated in all three seasons (Kharif, Rabi, and Zaid/Summer). However, its main commercial season is Kharif.
  • Note: In the state of Bihar, maize is predominantly cultivated as a Rabi crop.
• Temperature: Optimum for germination is 21°C, and optimum for growth is 32°C.
• Sowing Time:
  • Kharif: Last week of June to the first fortnight of July.
  • Rabi: Last week of October (for intercropping) or up to 15th November (for solo cropping).
  • Zaid/Spring: First week of February.

📏 6. Agronomy: Seed Rate, Spacing & Population

(Highly important for objective exams!)

• Normal / Hybrid Maize: 20 to 25 kg/ha.
• Composite Maize: 18 to 20 kg/ha.
• Sweet Corn: 8 kg/ha (Spacing: 75 x 25 cm).
• Baby Corn: 25 kg/ha (Spacing: 60 x 20 cm).
• Fodder Maize: 50 kg/ha (Spacing: 30 x 20 cm).
• Standard Spacing: Generally 60 x 20 cm or 75 x 20 cm.
• Plant Population:
  • Kharif: 65,000 to 70,000 plants/ha.
  • Rabi: 85,000 to 90,000 plants/ha.

💧 7. Fertilizers & Water Management

• NPK Ratio: 120 : 60 : 40 kg/ha.
• Fertilizer Application: Full doses of P & K and half of N are applied as a basal dose. The remaining half of Nitrogen is applied as a top dressing during the Knee-high stage. Maize is considered a heavy nitrogen feeder.
• Critical Stages for Irrigation:
  1. Silking Stage: This is the most critical stage. Moisture stress here must be avoided at all costs.
  2. Tasseling Stage.
  3. Knee-high Stage.
  4. Grain-filling Stage.
• Sensitivities: Maize is highly sensitive to both waterlogging and drought.

🌿 8. Weed Management

• Critical Weed-Free Period: The first 15 to 45 Days After Sowing (DAS) is the most crucial time to prevent weed competition.
• Chemical Control: The pre-emergence herbicide Atrazine is the most commonly used and effective chemical for weed control in maize.

🐛 9. Major Diseases & Pests

Make sure to memorize the scientific names of these specific pests and pathogens:

• Major Insect Pests:
  • Shoot Fly: Atherigona orientalis.
  • Stem Borer: Chilo partellus.
  • Pink Stem Borer: Sesamia inferens.
• Major Diseases:
  • Downy Mildew: Peronosclerospora maydis (or P. sorghi).
  • Leaf Blight: Helminthosporium maydis.
  • Charcoal Rot: Macrophomina phaseolina.
• Physiological Disorder:
  • White Bud Disease: Caused by Zinc deficiency (A frequently asked exam question!).

🚜 10. Harvesting

• Maize should be harvested when the cob turns completely yellow.
• The ideal grain moisture content at the time of harvesting should be around 20%. Delayed harvesting can lead to lodging and pest damage.