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Date:
Tuesday April 23, 2024

Categories:
Blog

Avocado and Plant Breeding: Advances in Avocado Breeding for Improved Traits

Introduction to Avocado Breeding

The avocado (Persea americana) is a tree native to South Central Mexico, classified as a member of the flowering plant family Lauraceae. The fruit of the plant, also called an avocado, is botanically a large berry containing a single large seed. Avocados are commercially valuable and are cultivated in tropical and Mediterranean climates throughout the world. They have a green-skinned, fleshy body that may be pear-shaped, egg-shaped, or spherical.

Avocado Breeding

Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. In the case of avocados, plant breeding is crucial for improving the quality and yield of the fruit.

Challenges in Avocado Breeding

Despite the potential benefits, avocado breeding presents several challenges. One of the primary challenges is the long juvenile period of avocado trees. It means that it takes several years for a newly planted tree to bear fruit, which slows down the breeding process. Another challenge is the large size of avocado trees, which makes them difficult to manage in a breeding program. Additionally, avocados have a unique flowering behaviour known as ‘synchronous dichogamy’. In this, the male and female flower parts open at different times, which makes cross-pollination challenging.

Advances in Breeding Techniques

Despite these challenges, significant advances have been made in avocado breeding techniques. Marker-assisted selection (MAS) is a process where a trait of interest is selected based on a marker (morphological, biochemical or DNA/RNA variation) linked to a trait of interest (e.g., productivity, disease resistance, and quality), rather than on the trait itself. This process has been used to select for disease-resistant avocado varieties.

Genomic selection, another advanced technique, uses genome-wide marker data to predict the genetic value of individuals in a breeding population. It has been used to improve the efficiency of avocado breeding programs.

Speed breeding, a method that uses extended daylight conditions to accelerate plant growth and development, has also been applied to avocado breeding to shorten the long juvenile period of the tree.

Improved Traits

 The primary goal of plant breeding is to improve the traits of the plant species. In the case of avocados, several traits have been targeted for improvement. One of the most important traits is disease resistance. Avocado trees are susceptible to several diseases such as root rot and sunblotch. Through breeding, varieties have been developed that show increased resistance to these diseases. Another important trait is fruit quality. This includes the taste, texture, colour, and shelf life of the fruit. Breeding has led to the development of varieties with superior fruit quality. Yield is another trait that has been improved. High-yielding varieties are more profitable for growers and can meet the increasing demand for avocados. Lastly, adaptability is a crucial trait, especially in the face of climate change. Varieties have been developed that can thrive in a range of climatic conditions.

Case Studies

There are several successful avocado breeding programs that serve as excellent case studies. For instance, the University of California’s avocado breeding program has been instrumental in developing disease-resistant varieties that are now widely grown. ‘Gwen’ is one such variety that is resistant to root rot and boasts excellent fruit quality. Another variety, ‘Lamb Hass’, is known for its high yield and is popular among growers. These case studies demonstrate the potential of plant breeding in improving the traits of avocados.

Future Prospects

The future of avocado breeding is promising. With the advent of biotechnology tools like CRISPR for genome editing, breeders will be able to make precise changes to the avocado genome. This could potentially open up new possibilities for trait improvement. For instance, it could become possible to develop avocado varieties that are resistant to a wider range of diseases, or varieties that can thrive in a wider range of climatic conditions. The use of these advanced tools could revolutionize avocado breeding and have a significant impact on the avocado industry.

Conclusion

In conclusion, advances in avocado breeding have led to significant improvements in traits such as disease resistance, fruit quality, yield, and adaptability. These advances hold great promise for the future of avocado production, ensuring that this delicious and nutritious fruit continues to be available for consumers around the world.