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Pre-Harvest Treatments

• Pre-harvest treatments significantly affect the physical and chemical properties of fruits, impacting their marketability and storage potential.
• Key factors influencing fruit quality include:

Fertilization

• Provides essential nutrients for tree and fruit growth, increasing fruit size, weight, and chemical content.
• Timing is crucial; nitrogen fertilization late in fruit development can delay ripening, prevent color change, and increase skin thickness (especially in citrus fruits). Insufficient fertilization or nutrient deficiencies can slow fruit growth and cause issues.

Irrigation

• Increased irrigation leads to softer fruits due to faster growth and thinner walls.
• Conversely, reduced irrigation results in harder fruits and smaller cell sizes. Increased water also increases cell size.

Pruning

• Reduces the number of fruits, improving fruit quality and directing resources to fruit development instead of foliage.
• Enhances fruit exposure to light for improved color.
• Prevents excessive tree height, facilitating easier harvest and reducing fruit damage.

Fruit Thinning

• Reduces the number of fruits, increasing fruit size, better color, and improved organic compound (sugars) content.
• Hand thinning or hormone treatments can be used.
• Avoid excessive thinning, as it may lead to overly large fruit with soft tissues, increasing physiological decay and reducing market value.

Pesticide Application

• Chemical applications can damage fruit by burning or degrading tissues, impacting shape and flavor.
• Some applications can alter chemical content, such as increasing sugars with certain compounds.

Training and Canopy Management

• Directs nutrients to fruit development, increasing fruit size and weight.

Planting Spacing

• Affects the absorption of minerals and organic matter impacting fruit development, shape, and appropriate color and vitamin production.
• Can influence light interception.

Rootstocks

• Fruit characteristics (size, color, taste, chemical composition) are influenced by rootstocks used in grafting.
• For example, vigorous rootstocks like sour orange tend to increase fruit size, while dwarfing ones like mandarin reduce fruit size.
• Rootstock can affect the final shape and color. For example, certain citrus grafted onto a particular rootstock may have different colors than same varieties grafted onto different rootstock.

Yield

• Increased fruit number leads to competition for resources, negatively affecting fruit characteristics, especially fruit size. Higher yields result in smaller fruit; conversely, lower yields result in larger and softer fruits.

Environmental Factors

• Climatic Factors (Temperature & Humidity): Low temperatures slow fruit growth; high temperatures can produce smaller, denser fruit. Coastal climates may have elongated fruit shapes, while hotter inland climates produce rounder ones due to cell size and internal tissue differences. High humidity may lead to softer fruit due to cell expansion.
• Wind: Wind can mechanically damage fruits by causing abrasion or friction.
• Soil Factors: Soil type, fertility, and drainage influence tree growth and consequently fruit development, size, color, ripening rate, and overall quality. Poor soil yields smaller, more rapidly ripening, and colored fruits. Rich soil generally yields bigger, and slower ripening, fruits that retain color longer.