AVOCADOS
AVOCADO PROPAGATION
Cultivars
Green-skinned Cultivar
Black-skinned Cultivar
Cultivars
There are 2 categories of avocado’s, green and black-skinned cultivars. This is some of the cultivars we use in South Africa and what we will decide on to use for the nursery. We will use one cultivar from each green and black skin avocado trees to begin with and to diversify. We will begin as a licensed nursery that uses cultivars (with premission) to propagate and get a income to then later begin to use more avocado cultivars.
Green-skinned Cultivar
- *FUERTE - It is green in colour with a thin waxy skin, which separates easily from the flesh. This fruit is available from March to July and is pear or ovoid shape. The Fuerte is an excellent quality fruit and has a rich creamy texture. The fruit stalk comes off easily when it is ripe.
- *PINKERTON - It has a thick rough green coloured skin that remains green when ripe. This fruit is available from April to July and has a definite thickish neck as opposed to the other varieties. The thick skin does not yield to pressure. The taste of the flesh is sometimes slightly sweet.
- *EDARNOL - It stays green coloured when ripe and the flesh has an excellent rich and nutty taste. The fruit is available from June to September and is characterised by a thick green coloured skin with small light brown speckles (lenticels). The skin shrivels at the stem end if picked when not fully mature.
Black-skinned Cultivar
- *HASS - The fruit is available from May to October in South Africa and is ovoid shape with a rough green skin, which turns blackish-purple when ripe. The flesh has a creamy texture with a slightly nutty taste. Medium-sized fruit with good shipping qualities. Popular taste, heavy production and a tendency towards alternate bearing. The thick skin is an advantage when serving half an avocado as the flesh can be easily scooped out.
- *GEM - The fruit is available from spring onwards, up to December/January. The Gem® is slightly ovoid in shape with a green skin, which turns blackish-purple when ripe. The flesh has a creamy texture with a superior taste. The relatively thick skin allows the flesh to be easily scooped out.
- *CARMEN-HASS - Carmen®-Hass has green fruit that turns purplish-black and produces fruit of similar size to the Hass variety, but that matures about 4 weeks earlier than normal Hass. The cultivar also has the ability to produce a big portion of its fruit outside the normal Hass season. Carmen®-Hass is available from November to March.
Cultivars We Use
There is a lot of research that goes into what cultivar is the best to use, but it differs because different cultivars grow better in different areas of the world. That's why it’s important to establish what market you want to propagate your product produce the best cultivar for. GrowNurs decided on a South African market to begin with and as the business grows to expand onto an oversees market.
The green-skinned cultivar we will use to propagate is the EDARNOL®.We have chosen this cultivar because it is highly preferred by the South African farmer market and it has a good resistance against disease.
We have chosen the GEM® cultivar for the black-skinned avocado that we propagate. It produces a great constant harvest and is also highly preferred by the farm-growers and the customers. It has a higher tolerance for low and high temperatures than other cultivars.
The technique we will use to propagate is grafting, the preferred cutting, as a scion, onto a already fully grown root system and root stock. We will grow out the root stock from a seed of the same cultivar, but it would be different in gene pools. We will inspect the growth and health of plants, if any root stock has diseases, illness or poor growing/rooting it will be discarded. Its discarded because we don’t want any disease to be carried onto the scion that will become the new tree. The scion that will be used comes from the same mother tree so that all the trees will have the same gene pools. When the scion has grown bigger and it has enough leaves, a vessel of nutrients (nitrogen, phosphorus, calcium) and hormones (auxin) will be placed above the root stock on the scion to stimulate root growth on the scion. When the scion has enough roots to survive on its own,it will be cut off at the bottom of the vessel. The root stock will be used again to put on the next cutting/scion to grow on.
Aftercare: Soil, Filtration and Irrigation
There is a lot of research that goes into what cultivar is the best to use, but it differs because different cultivars grow better in different areas of the world. That's why it’s important to establish what market you want to propagate your product produce the best cultivar for. GrowNurs decided on a South African market to begin with and as the business grows to expand onto an oversees market.
We have chosen the GEM® cultivar for the black-skinned avocado that we propagate. It produces a great constant harvest and is also highly preferred by the farm-growers and the customers. It has a higher tolerance for low and high temperatures than other cultivars.
Technique To Propagate
We will use cuttings in the juvenile phase from our preferred cultivar, the mother tree of our avocados. The cuttings we use we get from the grown trees we planted near our nursery in the Paarl area. Paarl have a good climate for avocados to grow naturally. We will get our mother trees, healthy and grown, from Westfalia Nursery and with our preferred cultivar. Westfalia has already agreed to sell us some of there mother trees with healthy and high quality genes.
The technique we will use to propagate is grafting, the preferred cutting, as a scion, onto a already fully grown root system and root stock. We will grow out the root stock from a seed of the same cultivar, but it would be different in gene pools. We will inspect the growth and health of plants, if any root stock has diseases, illness or poor growing/rooting it will be discarded. Its discarded because we don’t want any disease to be carried onto the scion that will become the new tree. The scion that will be used comes from the same mother tree so that all the trees will have the same gene pools. When the scion has grown bigger and it has enough leaves, a vessel of nutrients (nitrogen, phosphorus, calcium) and hormones (auxin) will be placed above the root stock on the scion to stimulate root growth on the scion. When the scion has enough roots to survive on its own,it will be cut off at the bottom of the vessel. The root stock will be used again to put on the next cutting/scion to grow on.Aftercare: Soil, Filtration and Irrigation
After the scion is cut off of the root stock, the nutrient and hormone vessel will be opened and the small tree will be planted in a planting basin. Its important in this stage of the avocado trees life to be treated delicately and have the right mixture of soil, good filtration and the right amount of irrigation.
Soil
The soil must have good drainage properties, because avocado trees roots have a tendency to rot easily with stagnant water, but it also need a lot of water frequently. That's why loose soils is preferred. We will use a sandy loam, limestone and decomposed granite particle soil for our trees. Avocado trees can grow in both acidic and basic soils, but they prefer a acidic pH of 6-6,5. The loose soils is also good for the root growing, compacted soils hinder root spreed and which can stunt the tree's growth and contribute to
root rot.
root rot.
Filtration
Important nutrients for avocado plants and the filtration we use:
Fertilizer applications require the right balance of minerals because the amount of each mineral in leaves are different. Thus, some minerals are required in greater amounts than others. Very simply, avocados need the right amounts of Nitrogen and Phosphorous for healthy metabolism, Calcium for good structure, Magnesium for good photosynthesis capacity, and Boron, Iron, and Manganese for good health.
The soil we use have good amounts of each mineral named above. With regular soil and leaf tests for the value of minerals in the plant,will help us to know what mineral is needed and what the plant still requires. It is important to know that some minerals like magnesium can be harmful to the plant when given in to much quantity. We will use a 2:2:1 mix of LAN:MAP:KNO3 filtration applied at 20g/tree, without touching the stem, as a general filtration. When values of other minerals is to low it would be added separately with the right amount.
Irrigation
Irrigation is very important for young trees, but too much water can be more unhealthy then to little water. Tensiometers will be used to regulate the moist in the soil and will be irrigated according to what the tree needs. Micros are used to irrigate the soil and spreaders are used to limit the irrigation area. The trees need about 10 liters of water per week and must have a good drainage system so that the roots will not rot.
Irrigation is very important for young trees, but too much water can be more unhealthy then to little water. Tensiometers will be used to regulate the moist in the soil and will be irrigated according to what the tree needs. Micros are used to irrigate the soil and spreaders are used to limit the irrigation area. The trees need about 10 liters of water per week and must have a good drainage system so that the roots will not rot.
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