The rising interest of consumers for avocado has skyrocketed the global demand for this fruit, and as a result, new areas are planted with avocado every year.
I planted my orchards 25 years ago in different fields (in 15 different locations) in the Chania region in Crete (Greece), where the microclimate is highly favorable for growing avocados. I selected to cultivate Zutano, Fuerte, and Hass due to their excellent adaptation to local conditions and the medium to high yields. As a farmer, I prefer Zutano because it can offer the highest yields.
As a trader (and exporter) myself, I prefer Fuerte for its better storability and prolonged harvesting period. The fruits can be harvested from the trees from November until May in Crete, allowing a more consistent market supply. Fuerte is also the number one choice of Greek consumers. On the other hand, Hass is the most popular among European consumers due to the higher quality and better taste of its fruits. As a result, all production of Hass avocados is exported.
Advice
I advise fellow farmers to cultivate more than one variety with different maturity times in order to spread the risk of losses and the workload during harvest. Since the plants start producing fruits after 3-4 years from their planting, the farmer needs to take into account many factors to make an informed choice regarding the avocado variety selection. Ideally, he/she can plant some "test" trees from different varieties to see their response to the local conditions.
What to consider when selecting an avocado variety
All varieties are classified into three horticultural races: the West Indian (Persea americana Miller var. americana), Guatemalan (Persea nubigena L. Wins var. guatemalensis), and Mexican (Persea americana Miller var. drymifolia). However, a large number of commercially interesting varieties are hybrids.
Some of the most important avocado hybrids are the result of crosses between:
- Mexican x Guatemalan varieties: Ettinger, Pinkerton, Fuerte, Bacon
- Guatemalan X West Indian varieties: Choquette, Beta, Lula, Semil 34, Monroe
Over the years, other important commercial varieties have emerged as the results of other crosses between the above races.
The choice should be made by considering the following:
- The environmental conditions of the area where the trees will be planted. Many varieties in the market can perform well in climatic conditions ranging from true tropical to warmer parts of the temperate zone. If the main limiting factor in the area of interest is the temperature, you should try to find a relatively tolerant variety. Avocados are generally sensitive to extreme temperatures and do not react well to fluctuations or abrupt changes.
The varieties that are tolerant to lower temperatures are described as "cold-hardy" avocados. These varieties usually can withstand temperatures ranging from -1oC-4.4oC (30-40oF). Among the most popular varieties, the following seem to have some degree of cold tolerance: Bacon, Duke, Puebla, Lula, Reed, Mexicola, Taylor, Tonnage, Choquette, Fuerte, Ryan, Stewart, Zutano, and Sharwill. In general, avocado varieties of the Mexican race are the most cold-tolerant. As a result, Mexican rootstocks are preferred to be used for grafted seedlings in colder areas. However, avocado farmer should not choose them if their field has salinity problems. West Indian avocados are the most sensitive to low temperatures (1).
Varieties that belong to the West Indian race are suitable for warm tropical climates. They are widely cultivated in different areas of India (Maharashtra, Tamil Nadu, and Karnataka) and the lowlands of Tropical America. In general, these varieties have been reported to be more heat tolerant. Some of them are Fuchsia (Fuchs), Simmonds, and Waldin. Despite its popularity, Fuerte is not the best option for cultivation in the tropics. A suitable alternative could be the hybrids of the race with Guatemalan varieties (see above). However, the Mexicola variety is well adapted both in warm and cold conditions.
At the same time, avocado is generally sensitive to high salinity, drought, and saturated soils. In fields with known history, the farmer should choose a variety (or rootstock) with high tolerance to such limiting factors.
- The market demand. This can reflect both the customers' preferences for specific varieties and the seasonal demand for the product. Suppose the farmers want to export their product to other countries. In that case, they must also consider the preferences of the local consumers and, of course, the resistance of the fruits to transportation and more extended storage.
Quality characteristics and morphology of the most popular avocado varieties
- Mexican race
In general, the varieties of the Mexican race produce small (250 g) fruits that ripen 6 to 8 months after flowering (end of fall-start of spring). The fruit has a thin green smooth skin that keeps its color even when ripe and the highest oil content (up to 30%). Especially in Mediterranean climates, one of the most popular varieties belonging to this race is Zutano.
Zutano
Zutano is characterized as a "season opener" since its harvesting period starts in early fall and can supply the market until early winter (2). It is a type-B variety and is preferred by the farmers due to its high and consistent yield and good cold tolerance. The fruit has a pear shape, is medium to large (0.168 to 0.400 kg), and has shiny, bright green skin. It is less rich, creamy, and tasty compared to many other avocado varieties. The tree can reach up to 12 m (40 feet) in height. The trees start to produce fruits at a young age (2-3 years from seed).
Other important varieties of the Mexican race (or crossed with it) are: Duke, Mexicola, (Ettinger, Pinkerton, Fuerte, and Bacon)
- Guatemalan race
The varieties of the Guatemalan race are the most important and widely cultivated in California. The trees bloom in mid-late spring, and the fruits ripen and stay on the trees up to 9-12 months later. The fruits are relatively large, weigh up to 600 g, and have thick, warty skin. The oil content in fruits ranges between 8 and 15%.
Hass and Fuerte are the most widely used varieties of the Guatemalan race. However, both carry important genes (characteristics) of the Mexican race (Bender, 2012). Furthermore, these two varieties are usually combined in the same field since they offer a good level of cross-pollination. Despite their excellent characteristics, the farmer, before selecting them, needs to take into consideration that neither are very heat-resistant (1).
Fuerte
Fuerte is one of the most loved varieties for exports. It can survive low temperatures making it an important cold-hardy variety. The fruit has the shape of a pear (pyriform) and weighs between 200 and 400 g. It has a good quality and oil content (up to 26%) and is tastier than Zutano but less tastier compared to Hass. Like a "classical" Guatemalan race, Fuerte offers a large window for harvesting that can allow a consistent supply to the market, but depending on the size of the orchard could be time-consuming for the farmer. The trees become pretty large, requiring more space to grow compared to other varieties. Its sensitivity to anthracnose and scab may limit its cultivation in regions-fields with a known history (3). Regarding flowering, Fuerte blooms early in the season and is a type B variety.
Hass
The Hass variety of avocados is the most commercially interesting in the world, mainly due to its superior quality, taste, and long shelf-life. In the United States of America, the Hass variety accounts for 80% of the production, while in California, America, and Greece this percentage varies. Hass is predominantly Guatemalan but also has some Mexican genes (1). The trees can become very tall and require cutting back, while the canopy looks like an umbrella (3). For the North hemisphere, Hass has type A flowers and is characterized as a summer avocado, with the harvest to take place during June-August. The fruit has a medium size and an oval shape. One of the most distinctive characteristics of the variety is the change of the fruit's skin color from green to dark purple when ripe and its hard, thick, and rough skin texture. Extra attention is needed because Hass is susceptible to Persea mites and thrips.
Other important varieties of the Guatemalan race (or crossed with it) are: Nabal, Taylor, Tonnage, Dickinson, (Ettinger, Pinkerton, Fuerte, Bacon, Choquette, Beta, Lula, Semil 34, and Monroe).
- West Indian race
Finally, the West Indian race varieties are primarily cultivated in South America and Asia (India, Indonesia, etc.) and need warm climates to grow. The fruit is medium to large, varies in form, and the skin is usually smooth, leathery, and glossy. It has the lowest oil content compared to the fruits of the previous two groups. They bloom at the end of the fall-start of spring (February to May for the North hemisphere) and require 6-7 (sometimes up to 9 months) from flowering to ripe.
Some of the most popular varieties of this race are Booth, Waldin, Simmonds, and Fuchsia, while as a result of crosses with Guatemalan race varieties are the Choquette, Beta, Lula, Semil 34, Monroe.
References
- https://link.springer.com/content/pdf/10.1007%2F978-3-319-06904-3.pdf
- https://californiaavocado.com/avocado101/avocado-varieties/
- https://www.jica.go.jp/project/english/kenya/015/materials/c8h0vm0000f7o8cj-att/materialspdf
Bender GS (2012) Avocado production in California. A cultural handbook for growers, 2nd edn. Univ Calif Exp Program, Ch. 2 pp 1–32
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