Mango Alternate bearing: 

Causes, Symptoms and Practical Control Methods for Farmers

Mango is known as the “King of Fruits”, but many mango growers face a serious problem called alternate bearing. In some years, the tree produces heavy flowering and fruiting, while the next year it produces very few or no fruits. This irregular production affects farmers' income and orchard productivity.

Understanding this problem and managing it effectively can help farmers achieve more consistent mango production year-round.

What is Alternate Bearing in Mango?

Alternate bearing is a physiological disorder in mango trees where the tree produces a heavy crop in one year (On Year) and very little or no crop in the following year (Off Year).

Because of this pattern, mango production becomes irregular and unpredictable.

This condition is also known as:

Biennial bearing

Irregular bearing

Erratic bearing

Many traditional mango varieties, such as Dashehari, Langra, Chausa, and Alphonso commonly show this problem. 

Symptoms of Alternate Bearing

Farmers can identify alternate bearing by observing the following signs:

• Heavy flowering and fruit set in one season

• Very poor flowering in the next season

• Reduced number of new vegetative shoots

• Poor fruit yield after a heavy crop year

• Uneven productivity in the orchard

Causes of Alternate Bearing in Mango

Several physiological and environmental factors contribute to alternate bearing.

1. Adverse Climatic Conditions

Unfavourable weather conditions, such as high temperature, drought, frost, or unseasonal rainfall during flowering and fruit development, can disturb normal flowering cycles.

2. Improper Orchard Management

Poor cultural practices such as:

Improper pruning

Nutrient deficiency

Poor irrigation management

Lack of canopy management, etc., can affect the tree's ability to produce regular flowers.

3. Genetic or Varietal Characteristics

Some mango varieties are naturally prone to alternate bearing because of their genetic makeup.

4. Age and Maturity of Shoots

Only mature shoots can produce flowers. If the tree produces excessive vegetative growth after a heavy crop year, flowering may be reduced in the next year.

5. Carbon to Nitrogen Ratio (C:N Ratio)

A higher C:N ratio promotes flowering, whereas excessive nitrogen leads to vegetative growth instead of flowering.

6. Pest and Disease Incidence

Serious attacks of pests and diseases, such as:

Mango hopper

Powdery mildew

Anthracnose can reduce flowering and fruit set.

7. Hormonal Imbalance

Plant hormones regulate flowering. Hormonal imbalances, such as gibberellins and cytokinins, can disrupt the flowering cycle.

Practical Methods to Control Alternate Bearing in Mango

Although alternate bearing cannot be completely eliminated, it can be significantly reduced through proper orchard management.

1. Selection of Regular Bearing Varieties

Planting varieties that show regular fruiting behaviour is the most effective long-term solution.

Examples include: Bangalora, Neelum, Rumani, Mallika, Amrapali, Ratna, Sindhu

These varieties are known for more consistent yields.

2. Proper Orchard Management

Maintaining healthy tree growth is essential.

Important practices include:

• Regular pruning

• Balanced fertilizer application

• Weed control

• Proper irrigation management

• Canopy management

Balanced nutrition is especially important to maintain proper vegetative and reproductive growth.

3. Deblossoming in the On Year

During heavy flowering years, partial removal of flowers (deblossoming) helps reduce excessive fruit load.

This allows the tree to conserve energy and promotes better flowering in the next year.

4. Smudging (Traditional Method)

In some regions (Philippines), farmers practice smudging or smoking under mango trees.

This traditional technique creates mild stress and can help induce off-season flowering in certain conditions.

5. Use of Growth Regulators

Plant growth regulators can help manage alternate bearing.

Commonly used chemicals include:

• TIBA (Triiodobenzoic Acid)

• Cycocel (CCC)

• Alar (Daminozide)

These are applied during flower bud differentiation or after harvesting in the on year.

6. Paclobutrazol Application

Paclobutrazol is widely used to regulate mango flowering.

Application method:

• Soil drenching around the tree basin

• Dose: about 5 g per plant

• Time: August to October

Paclobutrazol suppresses excessive vegetative growth and promotes more regular flowering and fruiting.

Alternate bearing is one of the major productivity challenges in mango cultivation. However, with proper variety selection, good orchard management, and the use of growth regulators, farmers can significantly reduce irregular fruiting.

Adopting these practices helps maintain stable mango production and better farm income.

Frequently Asked Questions (FAQ)

1. Why do mango trees produce fruit only every alternate year?

Because the tree exhausts its resources during a heavy fruiting year and requires time to recover, it results in reduced flowering in the following year.

2. Which mango varieties show less alternate bearing?

Varieties such as Neelum, Amrapali, Mallika, Ratna, and Sindhu are known for more regular fruiting.

3. Which chemical helps control alternate bearing in mango?

Paclobutrazol is widely used to regulate vegetative growth and promote regular flowering.