Mango (Mangifera indica) is one of the most important tropical fruit in India. Mango flowering is a critical stage as it directly affects the yield of the fruit. Flowering in mango is highly dependent on the variety and environmental conditions. Thus, proper management strategies taken during the mango flowering stage can improve the potential number of fruit production.

Floral biology

Pollination and Flower initiation

Fruit drop in mango is a serious problem causing heavy yield losses. About 99 % of the crop is lost due to drop of bisexual flowers and immature fruits. The intensity is maximum within 15 days after pollination/anthesis, in which about 60-70 % bisexual flowers and immature fruit drop within a short period of time. In general, only 0.01 % of the pollinated perfect flowers set fruit.

Factors governing flowering:

1. Physiological and Environmental factors

• Vegetative growth & flushing episodes
• Florigen promoter: A substance that is synthesized in leaves, moved through phloem to the buds and are induced to flower
• Number of leaves
• Temperature

Low temperatures around 15-18°C and 6-8 months old, matured shoots have a strong possibility for floral growth initiation.

2. Phytohormones and carbohydrates

Consistent decline in gibberellins with increase in cytokinins and abscisic acid in combination with sufficient build-up of carbohydrates in the buds approaching bud burst stage ensures floral inductions in mango.

3. Pest and Disease incidence:

• High humidity, frost or rain, cloudy weather during the flowering period increases pest and disease infestation leading to risk of losing flowers and premature fruits, hampering mango growth and flowering.
• Mango hoppers, gall midge, mealy bug and leaf webber are the major pests and powdery mildew, mango malformation and anthracnose are the diseases.

Methods to overcome flower drop and improve fruit setting:

1. Growth Regulators (PGRs)

• Flower induction, apply Paclobutrazol to the soil 90 days before the expected flowering (typically August or September)
• Fruit retention, spray GA3 (Gibberellic Acid) at 20 ppm during later development stages.
• Fruit drop: Foliar spray with Multiplex Nagamruta (Naphthalene Acetic Acid) at 0.25 ml/L should be done when the fruits reaches the pea or marble stage
• Potassium Nitrate (KNO3) at 3-5 gm/L has potential for inducing flowering. Use twice, at first flower bud differentiation, another spray during the full bloom stage.

2. Nutrient Management

• Pollen vitality and successful pollination: Spraying of Multiplex Allborich at 1 ml/L or Multiplex Borax at 2 g/L before flowering and after fruit.
• Fruit set and retention: Multiplex Twin at 3 g/L when fruits are at the mustard or pea size.
• Strengthen cell walls and prevent fruit drop: Multiplex Pranam Ca at 3 ml/L during flowering & fruit development.
• Foliar spray with Multiplex Mango Special at 2.5 g/L before flowering, during flowering and after fruit set will provide secondary nutrients and micronutrients.

3. Pest and disease management

• Use Multiplex Nagmida 0.5 ml/L and Multiplex Vishesh 2 gm/L, Tecozo 1 ml/L, Duo-care 1 ml/L

For improving mango yield, one should focus on