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Cold-hardy avocado breeding for the PNW

Seeking to find the hardiest Mexican-race avocado cultivars and landraces available, then interbreed them in a greenhouse and trial their seedlings in zones 8-9 in the Pacific NW.

Currently we have ~20 cultivars on multi-graft greenhouse trees, ~50 seedlings, and we are looking for new cultivars and volunteers to grow seedlings and grafted trees in this region. Cultivars that reliably produce hardy seedlings will be hand-crossed in our greenhouse to provide seeds for the project, and any seedlings that flourish will be grafted back onto the greenhouse trees to be included in the breeding pool. High mortality is expected initially, but hopefully as the project progresses that will decline in future years.

Researcher background
I have no formal horticultural training, but have spent the last three years reading avocado research papers, collecting and grafting specimens, collecting and germinating seeds, and visiting marginal areas where avocados are grown in backyard settings to learn what the greatest challenges will be in our cool & wet climate.
Are you seeking volunteer growers or other types of volunteers?
Yes, seeking volunteer growers
How many volunteers do you need?
What will you ask volunteers to do?
Volunteers who live in other marginal climates where avocados are occasionally grown will be asked to locate hardy specimens and provide cuttings. Volunteers in this region will be asked to plant seedlings or grafted trees and provide updates on their health periodically, as well as cuttings from any especially successful seedlings.
Is this a multi-year project?
Can volunteers expect to be able to keep some germplasm (seeds, bulbs, cuttings, spores, etc) at the close of the project?
Yes, of course
Researcher Location

United States

Project Updates

Timeline for tree distribution

project update by
Friday, August 12, 2022 - 03:20

I've had a few questions recently about when volunteers should expect to receive trees.

In short, a link will be sent to all participants during the fall or early winter (November-ish 2022), allowing volunteers to provide details about their rough geographic location and the number of trees they hope to adopt/host. That link will also be added to this profile once it goes live.

In order of registration, volunteers in our research area should expect to be contacted over the winter to coordinate delivery of their tree(s). The first trees will be distributed in late spring of 2023, and new trees will be distributed each year thereafter around that time of year. The number of trees available should increase each year as our breeding trees grow larger and produce more seed, but the first distribution (2023) will include only a couple dozen trees.

As casualties are expected to be high in early years, priority will be given in later years to those who need to replace dead trees.

Please direct questions to info(at) drymifolia(dot)org.


project update by
Thursday, August 11, 2022 - 07:42

I am interested in following this project in order to maybe learn more. I don't know if i will be of much practical help because i live in brittany, france. I am trying to grow avocadoes outdoors where i live. The climate where i live is comparable to the pacific northwest. I have one mexicola and one fantastic seedling growing outdoors.
My findings for now are that they die back down in winter but regrow from the roots the following year.
Only by protecting them can they be prevented from dying in winter. I don't fully understand the exact reasons but temperature is only one, and not the most important, factor.
I have another fantastic seedling that i planted in my polytunnel and it survived the winter just fine despite having been exposed to the same temperatures, but protected by the polytunnel.
Young avocado plants seem to really dislike the long weeks and months of cold moisture descending down and freezing on their leaves if grown outdoors