🌾Wheat -- King of Cereals (Complete Cultivation Guide)

When Dr. Norman Borlaug’s Mexican dwarf wheat seeds arrived in India in 1963, the country was importing millions of tonnes of grain to feed its people. Within a decade, those seeds transformed India into a wheat-surplus nation. Today, wheat remains the second most important food crop after rice, and its story — from Norin-10 dwarfing genes to modern rust-resistant varieties — is one of the most examined topics in agriculture exams.

In the previous lesson, we covered Rice — India’s largest food crop. Wheat contrasts with rice in almost every way: it is a Rabi crop requiring cold weather, long days, and far less water.

This chapter covers:

1. Basics and global standing — Triticum species, ploidy, area, and production rankings
2. Climate and sowing — temperature requirements, sowing depth, FIRB, zero tillage
3. Green Revolution story — Norin-10, Borlaug, dwarf gene classification
4. Varieties — single, double, and triple gene dwarfs, mutant varieties
5. Weed and harvest management — Phalaris minor, harvest index, yield concepts

All sections are high-yield for IBPS AFO, NABARD, and RRB SO exams.

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Basics

• Botanical name: Triticum spp.
• Family: Poaceae (Gramineae)
• Origin: South West Asia (Turkey)
• Wheat is a self-pollinated, C3, and hexaploid (6n = 42) plant. Having six sets of chromosomes contributes to its genetic diversity and wide adaptability.
• In India, wheat is the second most important staple food crop after rice.
• Wheat is known as King of Cereals owing to its widespread cultivation and central role in global food security.

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Global Standing

• India’s share in global wheat production: 11.78% (2015-16).
• India’s share in global exports: about 0.40% (2015-16).

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India

• National average productivity: 26.5 q/ha.

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Botany

Triticum Species

• T. aestivum is the most important species, occupying >90% of wheat area and 87% of total production. It is the bread wheat used for chapatti and bread.
• Research stations:
  • Modern bread wheat: CIMMYT, Mexico — the centre that drove the Green Revolution.
  • Indian Institute of Wheat and Barley Research, Karnal.
  • AICRP on Wheat & Barley Improvement, Karnal.

Grain Composition

• Protein content: 10-11% (Gluten). Gluten gives dough its elasticity and binding quality.
• Chapatti/baking quality is mainly governed by Gluten strength.

Morphology

Root System

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Climate

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Sowing

• 90% seed germination occurs 4-8 days after sowing.
• Germination: Hypogeal — cotyledons remain below the soil.

Sowing Date

Sowing Depth

• Dwarf wheat must be sown at only 5-6 cm depth because they have shorter coleoptiles. Sowing at 8-10 cm results in poor germination.
• The coleoptile is the protective sheath over the emerging shoot; if it is shorter than sowing depth, the seedling cannot emerge.

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FIRB (Furrow Irrigated Raised Bed)

• Uses 25-40% less water than flatbed methods.
• Improves crop yields by >20%.
• Saves 30-50% wheat seed compared to flatbed planting.
• Particularly advantageous where groundwater levels are falling and herbicide-resistant weeds are increasing.

Zero Tillage

• Zero-till drill (seed-cum-fertiliser machine) developed at GBPUAT, Pantnagar (Uttarakhand) for the rice-wheat system — direct sowing without ploughing.
• Seed rate is 20-25% higher than conventional (optimum: 140-150 kg/ha).
• Rice stubble should not exceed 15 cm height.

Surface Seeded Technology

• In parts of North-Eastern India, soil stays wet too long after rice harvest for tillage. Dry or soaked wheat seeds are broadcast before or immediately after rice harvest.
• Reduces production cost to 70-75% of conventional methods.

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Seed Rate

• Test weight: 40 g (Phalaris minor test weight is only 2 g — a useful comparison for identifying this weed).

• Ug99 resistant varieties: DBW 17, PBW 550, Lok 1, Turja. Ug99 is a highly virulent race of stem rust posing a serious global threat.
• Most suitable cropping system: mixed cropping (Wheat + Mustard, Wheat + Chickpea).
• Intercrop: 4-5 rows of wheat in 2 rows of sugarcane.
• Relay cropping: Wheat in early-planted potato is a high-bonus system.
• Maximum yield requires 500 tillers per m2.

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Irrigation Management

Wheat requires 4-6 irrigations depending on soil type and rainfall. The most critical irrigation is at Crown Root Initiation (CRI) stage, approximately 20-25 days after sowing. Missing CRI irrigation can reduce yield by up to 30% because crown roots form the permanent root system that sustains the plant for the rest of its life.

• Critical stages for irrigation: CRI (most critical), Tillering, Late Jointing (Booting), Flowering, Milk, and Dough.
• IW/CPE ratio: 0.9 for irrigated wheat.
• Anti-lodging chemical: Cycocel (CCC / Chlormequat chloride) — a growth retardant that shortens internodes by inhibiting gibberellic acid synthesis, reducing lodging risk in heavily fertilised fields.

Fertiliser Management

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Wheat Varieties — The Green Revolution Story

The introduction of dwarfing genes was the cornerstone of the Green Revolution in wheat.

• Lerma Rojo is resistant to all three rusts (yellow, brown, and black).

Pusa Yashasvi (HD-3226)

• Released by IARI with the highest genetic yield potential among Indian wheat varieties: 79.6 q/ha.
• Higher content of zinc, protein, and gluten.
• Highly resistant against all major rust fungi: yellow/stripe, brown/leaf, and black/stem.
• HD-2967 (Pusa Borlaug) and Pusa-3086 (Pusa Gautami) together cover 40% of India’s wheat area (IARI).

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Weed Management

• Phalaris minor has developed herbicide resistance in many areas.
• Common herbicide: 2,4-D (post-emergence). The milking stage is sensitive to 2,4-D — spraying at this stage causes grain shrivelling and yield loss.

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Harvesting

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Important Wheat Varieties ^{Asked in AFO/NABARD}

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Key Wheat Growth and Yield Concepts

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Summary Table — Wheat at a Glance

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Wheat Cultivation: Practical Decision Guide

Sowing time is the single most critical factor for wheat yield.

Irrigation scheduling — 6 critical stages (Crown Root Initiation to Dough):

If only one irrigation is available, give it at CRI stage. If two, give at CRI + flowering. This is among the most frequently tested facts in AFO exams.

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Summary Cheat Sheet