Factors affecting the severity of sunburn in pistachio Iranian Pistachio fruit are:

Intensity and duration of sunlight and increase in ambient temperature.

All the factors that increase the reflection of solar radiation increase the intensity of sunburn, for example, in cases where the soil surface is due to salinity, shiny and white, due to the almost complete reflection of solar radiation energy, sunburn on the fruits of the branches. High pistachios are formed.

The lighter (sandy) the soil texture, the lower its moisture storage. On the other hand, the reflection of sunlight in sandy textures is more. Therefore, more sunburn occurs in sandy tissues.

Low relative humidity and low vegetation on the garden surface.

Thick green skin and green skin and bony skin due to genetic and nutritional factors.

Severe pruning of a part of the tree to expose some of the fruits that were previously in the shade to strong sunlight.

Lack of proper direction of planting rows due to climatic conditions and latitude.

Pest damage such as age, skin-eating moth and fruit-eating moth damage green skin and bony skin and increase fruit sensitivity to sunburn.

Gonorrhea and nematode diseases of pistachio root glands increase sensitivity to sunburn due to reduced leaf cover and impaired absorption and movement of nutrients.

Increasing the length of irrigation cycle, especially in the hot months of the year, intensifies sunburn.

Irregular irrigation and water stress reduce the moisture of green skin and intensify sunburn.

Rainfall and spraying and untimely spraying on fruits during intense sunlight in July and August, causes water droplets on green skin. These water droplets act like a magnifying glass and intensify sunburn.

Damage to the green skin of pistachio fruit due to factors such as foliar spraying, improper spraying and hail causes stains on green skin and sunburn intensifies. It is more common, because alkalinity is also seen as a spot, sunburn is also seen as a spot in the garden.

Calcium deficiency due to too much magnesium in the soil solution increases the fruit's sensitivity to sunburn. Pistachio fruit needs a lot of calcium due to its bone tissue. Calcium deficiency may not be observed in the leaves, but the amount of calcium is not enough for proper fruit growth.

Nitrogen poisoning in pistachio fruit is similar to sunburn, except that gum comes out of the tips of some seeds.