The apricot (Prunus armeniaca) is a stone fruit, as are plums, peaches, nectarines, cherries, and almonds. Stone fruit have a single seed covered by a hard, thick seed coat (or ‘shell’); together the seed (or ‘kernel’) and the seed coat are called a ‘pit’ or ‘stone’. Both the kernel and the shell have economic uses in addition to the food value of the fruit flesh.
Apricot blooms early in spring and has a short maturity period, so that it is ready for fresh market in early summer (May or June) in the plains or September to October in the highlands. Apricots are grown on trees that reach heights of 3 to 13 m. The fruit is 3.5 to 6.5 cm wide and require 3 to 6 months to develop and ripen. After harvest, the apricots have extremely short shelf life and need to be eaten fresh within a few days; otherwise, the fruit should be dried or processed for juice, jam, or canning. Flowers contain both male and female parts and most apricots are self-fertile, although they will set a better crop if another variety is available as a pollinizer. A few apricots are not self-fertile and require compatible pollinizers. Pollination is by insects, usually honey bees. The trees have separate buds for flowers and leaves and the flower buds are more susceptible to killing frosts or too little chilling, which can also kill the flower buds. Flowers and fruit form on both one year-old wood and on long-lived short shoots (spurs). Spurs are productive for 3 to 5 years and the highest quality fruit is borne on younger spurs. Most apricots begin fruiting in their second year, but substantial bearing does not begin until 3-5 years. Fruit require 3-6 months for development, depending on cultivar. The fruits vary in size from 30 to 120 grams. The pulp of the fruits is yellow, orange, or white. The pulp is dense, fleshy and of high quality. Sugars’ contents are 6.2–20%, acids’- 0.25–1.8%. An average crop from a 20–30 year-old tree reaches 150–600 kilograms, and 100-300 centers from a hectare. Varieties differ based on Cold-tolerance and chilling requirement, Precocity (how young a tree is when it starts blooming), Time of bloom and maturity, Fruit size, shape, skin and flesh color, firmness, freeness of pit, flesh texture and taste Crop load Disease resistance Planning the orchard.
When apricots are not grown on their own roots, the scion variety is grafted onto a rootstock which is produced from seed (then called a ‘seedling’), or produced from cuttings. The two forms of grafting used to produce apricots are (1) bud grafting and (2) whip and tongue grafting.
Diagram illustrating the bud grafting technique
- Cut a slice of bud and bark from the parent tree.
- Cut a similar sliver off the rootstock, making a little lip at the base to slot the scion into.
- Join the two together and bind.
- In time, the scion bud will grow into a shoot, which will develop into the desired tree.
Whip and tongue grafting
Diagram illustrating the whip and tongue grafting technique
- Make a sloping cut in the rootstock with a ‘tongue’ pointing up.
- Make a matching cut in the scion wood with a ‘tongue’ pointing downwards.
- Join the two and bind with tape, covering the graft well.
Site selection and preparation
Production depends on tree size, vigor and ability to crop. The factors most limiting tree size in Nangahar fruit-growing areas include:
- climate, especially lack of abundant water by rain or irrigation, and frost, where winter temperatures may be -5 to -15 oC. If frost occurs in spring just before or during bloom, the crop can be destroyed.
- soil—deep, fertile soils optimize growth; poor soils restrict growth.
- fertility—to be productive, trees do best with applied fertilizers.
Deep, well-drained sandy loams with good moisture and nutrient-holding capacity are the best soils for apricot growing. Do not plant in salty (saline) soils. Full sunlight nearly all day long is essential. Trees that do not receive at least 6-8 hours of direct sunlight each day will produce long thin branches with few flowers and fruits. Here’s a simple test to determine your soil’s internal drainage—to see if you have a good site for fruit trees. Dig a narrow hole 1 meter deep and fill it up with water. If the water is gone within 24 hours, you’ll have no trouble growing fruit and nut trees. If the water is gone within 48 hours, the soil is acceptable but can give problems. If water is still in the hole after 48 hours, grow vegetables or flowers instead.
Planning the orchard to reduce the danger of frost at bloom and young fruit stage: Trees planted in open areas and trees exposed to cold prevailing winds are most likely to suffer frost damage. Low areas will collect cold air; avoid planting in depressions or basins. Planting near structures or walls, especially those with a southwest exposure, will take advantage of heat absorbed by the structure.
- Do not plant in low areas where cold air is trapped by surrounding hills or vegetation.
- Make sure the ground is firm, moist and exposed to sunlight by removing ground cover or keeping it low and not cultivating the soil during the cold months.
- Plant on north-facing slopes to help trees bloom later. The best way to reduce cold damage is to maintain healthy trees. Use cultural practices that induce and maintain dormancy in winter. These methods include no late summer or fall fertilization or pruning. Vigorous trees may recover from cold injury. Weak trees that show disease, insect damage, or nutritional deficiencies are the most severely damaged and the slowest to recover. Grass, weeds, and straw mulches prevent heat from entering the soil during the day, so less energy is stored for release at night. Keep the ground around the tree as clean and free from mulch, weeds and ground cover as possible. Avoid planting a cover crop in the orchard, or follow the guidelines under the section ‘Cover crops’.