Growing Avocados from Seed - Backyard Avocado Selection

This is one of a series of short articles I originally wrote on my avogene blog. Most of the articles will transferred to my website, perhaps with some editing on the way.

Author's motives

I am a ‘non-scientist’, retired, a home gardener on a ‘lifestyle block’, and my interest in avocados is a subset of a life-long general interest in food plants, particularly fruit and nuts.

I started out with the idea of growing and selling fruit of some of the ‘old school’ and some of the new avocado varieties (to cover some of the costs of my hobby when on a pension income), but in the end I decided it was too much work for too little reward – especially as the few good areas for avos here have increasingly been affected with phytopthora.

Anyway, ‘gardening’ for me is pretty much planting the tree and doing very little else thereafter. The results – or lack thereof – reflect my negligent style. Not a good attitude for a commercial avocado grower!

The non-monetary reward, really, is that it is quite interesting fiddling around with edible plants, and because I am a home gardener I can grow any ‘uneconomic’ plant I want.

As a result, we have a smattering of pecans, bags of macadamias, a variety of cherimoya, and so on. Usually bird pecked or possum-damaged, but it doesn’t matter that much, especially when my partner is a compulsive bottler and jam-maker.

I came to realize that ‘avocados’ are more than ‘just Hass’, so they excite my ‘huh, that’s interesting’ gland. Which, as my off-sider points out, tends to bouts of oversecretion.

Over the years a small number of avocado trees resulting from random seeds originally planted as rootstocks have fruited. Self sown seedlings have also popped up and fruited. It is always fun to see what the fruit are like, because the home gardener is not shackled by the tight requirements of commercial cultivars.

What I hope to achieve

The home gardener doesn’t give a toss if the fruit are small, big, thin skinned, subject to scarring, doesn’t keep, is a funny shape, the wrong color, crops only modestly etc.

But now that the average size home garden is not much bigger than a sheet of A4 paper, the home gardener does care a great deal about how big the tree is.

So, in retirement, I am throwing in a few seeds of whatever interesting (non restricted) avocado cultivars I can find in the hope – and it is a very faint hope indeed – that a small avocado tree with a small ‘footprint’ can be found for todays micro-garden. Yes, there is now VB33 (branded as 'Cleopatra') which is relatively small (3 meters high and wide). But I think a more slim-line small tree would be useful. But where to find interesting seed-parent trees?

The challenge of avocado seedling selection

Sadly, the ‘official’ New Zealand avocado variety collection (curated with 50% taxpayer funding) was mostly chainsawed in the late 1990’s. Wish I knew their plan before the deed was done. Still, as my mom-in-law used to say “if wishes were horses, beggars would ride”.

I am not an avocado breeder. Avocados are all but impossible to ‘breed’ in the conventional sense of controlled pollination, large numbers of progeny, re-selecting and re-crossing and so forth. In truth, the best you can do is stick in some seeds from an avocado cultivar you think is interesting, and hope for the best. And as seedlings take 5 to 20+ years to fruit (if they fruit at all) planting a few seeds late in life seems a little futile.

But it is interesting and fun.

And in the unlikely event a small tree was found, I would be very happy to have contributed to the dietary quality of the average householder. And if the tree was really small, it might fruit in a large pot, and become part of a mobile orchard. After all, dwarf apples and peaches will fruit in pots, so why not a dwarf avocado?

Will a dwarf avocado come from commercial programs? Doesn’t seem like it right now. Dwarf avocados were once bred in Mexico, but now seem to have fallen off the radar. Perhaps they weren’t ‘commercial’.

There is some hope - in the long term. To understand why there is hope, we need to take a small side trip. Into the revolution driving modern fruit breeding; and, unlikely as it might seem, and the introduction of contract law into plant breeding and orcharding.

A major problem for commercial growers is that avocados are now reaching the point of being a commodity, and therefore profitability is falling. Commercial success now depends on being a low-cost producer, and not too far from your market. These conditions are found in only a limited number of countries with ideal climates, cheap labor, political stability, plentiful water, and good geographic location. So what’s the ‘fix’ for the rest, who don’t have these advantages?

Well, in the kiwifruit, stonefruit, and pipfruit industries the unstoppable trend is to breed unique and desirable fruit varieties that are exclusively licensed under contract law to a small ‘club’ of limited number of growers worldwide. The idea is to limit supply and keep up the prices for these elite varieties. These 'special' varieties are differentiated in the market place by branding. And, of course, they promoted as a being ‘a cut above the rest’.

The 'club' trees don’t make it to the home gardener unless they fall dramatically from commercial favor. If the ‘club’ no longer uses them, they may (or may not) allow them to be released under plant patent law (as the breeder is then entitled to a royalty for each plant sold).

Before the so-called ‘club fruit’ concept caught on, home gardeners used to receive the commercial ‘cast-off’ varieties of the horticultural industry. That now seems to be coming to an end.

As a result, for the most part, we only have the ‘old school’ avocado varieties that were available decades ago – if they still exist. So where will new avocado varieties for the home garden comne from? Maybe from you! That seedling growing from the compost in your back yard may be the only source of a new avocado variety for the home garden – as long as it has some fault that disqualifies it from becoming a commercial cultivar! And chance seedlings do have a small history of making ‘the big time’.

After all, today’s commercially dominant Hass variety grew from an ungrafted rootstock tree grown from seed of the Lyon cultivar. Lyon, very likely the seed parent of Hass, was in turn a home garden tree growing in Mrs.Lyon’s front yard in – yes – Sunset Boulevard, Hollywood!

The irony is that as commercial cultivars improve – in part maybe due to application of gene technology – every home gardener who plants an avocado seed has a better and better chance of coming across a good quality avocado. Whether it is small enough for the backyard is a different matter. We have to wait for the few commercial breeders in the world to once again look for this specific characteristic.

Small trees for climate change

As human induced climate change pumps more and more energy into the weather system we may have much higher energy winds. This may drive an effort to develop smaller trees capable of withstanding wind damage.

'Marker assisted selection' might accelerate the hunt for smaller trees with leaves that don’t snap or shred in high winds. This is a genetic screening technique that can pick out indivduals seedlings likely to contain the characteristic (or characteristics) of interest. This means seedlings without the character can be thrown out, a huge saving in money, and, ultimately, time.

My guess is that eventually, fruitful small trees will be bred for the commercial orchardist, and finally appear on your supermarket shelves. Chance seedlings from these small varieties will, in turn, be more likely to be be smaller – suiting the home gardener. I see this process as all but inevitable, but it may take a rather long time.

Motives

So there you are, my main motive is fun, and, if I am lucky, to make a contribution to the interests of the home gardener, and by extension, to peoples health.

It’s a tremendous lot of fun cheer-leading from the sidelines of a commercially-funded ‘science-game’ in which the average person barely understands the rules, and can only ever be a spectator. But genetic science has a necessary language of its own, and many complex concepts describing the behaviour of genes. Learning just a little about the behaviour of genes is not particularly fun, but it is certainly interesting.

My efforts to gain a level of understanding of the rules of the ‘molecular game’ is also an important reason for this blog, even when the molecular work is of no direct importance to my interests.

But complexity of genetics or not, from my home gardeners perspective it’s simply fun to throw a few seeds in the ground and see what you might get. E v e n t u a l l y…!