Fuerte avocado tree: male flower dominance as the cause of poor fruiting?

Hello,

Fuerte is my favorite avocado, but I know it has a reputation for bearing inadequate crops. There are some theories as to why that is true:

  1. Alternate bearing. But most find it is not always on alternate years.

  2. Cold temperature. That makes sense to me.
    Avocado Fuerte

  3. Bee preference for other flowers. But mine love it as much as citrus. The tree is closer to their hive, maybe that is why, but they have always covered the tree.

  4. Early flowering. If it flowers before the A type cultivar you have then you don’t really have a pollinator (though most say you don’t need one in my area). I have seen Fuerte flower long before anything else so I was trying to find a good pollinator that blooms that early, when I noticed something on the flowers. So I am going to add theory #5:

  5. Male dominance flowering (at least for me, at least this year)

Fuerte is a B flower, so it is male in the morning and female in the afternoon. But tell that to my 2 Fuerte trees. When it was cold a month ago it had nice overlap, with male and female at the same time for the middle of the day. But just as that started we got pounded with a week and a half of rainy weather. Since then I have watched the flowers closely and they remain male almost all the time. A couple times later in the afternoon and into the early evening there were some female flowers but still way less than half of them, and way less than half the day. And most days there are no female flowers at all.

Could this problem explain Fuerte’s poor cropping? I have never read this before so maybe I am misinterpreting something but the flowers definitely look male all day long most days. Maybe this does not matter and the bees can knock around enough pollen to pollinate the female parts of an avocado flower during the male phase? If that is not the case then I think I might know why I get light crops. My fuerte is in male phase 90% of the time during the key pollination season right now.

Thanks for your thoughts.

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I have posted it a couple of times elsewhere, but I found this a plausible hypothesis why “B” type avocados (other than Bacon and Zutano) produce poorly in cooler areas

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Great article! Great insights from people who were intellectually curious, determined, and subject to adversity (garden adversity, anyway, from pushing limits on climate).

After a warm week and some lag time my fuerte went back to the paradigm of male in the morning and female in the afternoon. It varied by the day. One day it was completely female the whole afternoon. Another day it was only the last couple hours of the day. Another day it was half male and half female. The bees are on to other things now. I hope I get a good crop. That article helps me have lower expectations from fuerte and B types. But at the local farmers markets the same people have fuerte every year so maybe this will improve with time here.

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You can also graft some A (or reliable Bs) varieties to your tree

2022 update on Fuerte:
Flowers from November to early March were male every time I checked, morning or evening. Extensive flowering. No fruit set thus far.

Just this week they showed female in the afternoon. Not as many flowers left. But the bees are active so maybe I will get some fruit….

And they are complementing hass and reed nicely, which are coming into bloom.

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I had a chance to go down to Epicenter Nursery - really the owner’s home - and got a two hour tour and quite a few lessons, both on grafting and on which trees do well in the Bay Area. The owner is adamant that A type avocado trees are much better suited to cooler, milder climates. I was able to get a few unusual scions to graft - unfortunately I am an Avocado killer - murdered quite a few, yet still keep trying.

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First female stage flowers on Fuerte I have seen this season.

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They are amazing, aren’t they? Their nursery/home is so picturesque when I visited them on a cloudy evening in May. You can feel their enthusiasm in growing avocados in chilly coastal Santa Cruz and sharing the knowledge with others. What varieties did you get scions for?

I went there again in fall to get an Apple tasting box of different varieties.

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Relevant to this thread, the Western Australia ag ministry has some really good info online about growing avocados in cool temperatures, including both data they have collected when looking for a Hass pollenizer and also publications that summarize other studies, like this:

Research by Sedgley and Grant (1983) into other varieties, both type A and B, has shown similar effects to different temperature regimes, though with some differences between varieties.

The delaying effect to type B varieties is so pronounced at low temperatures that the functionally female stage was often not recorded. This has a dual effect:

If there are few functionally female flowers then the cropping potential of the type B varieties will be severely affected.
Delaying of flower opening has been recorded to result in the peak pollen release period occurring during the night (Sedgley and Annells 1981).

Source:
https://www.agric.wa.gov.au/spring/challenges-growing-hass-avocado-cool-regions

The three cultivars flowering in my relatively cool Seattle greenhouse (Duke, Royal-Wright, Aravaipa) have definitely also had extended male phases and only brief female ones, often only very early in the morning or overnight. Those grafts are just over a year old, though, so that fact could be impacting mine as well.

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Their hypothesis about B types is interesting. But that logic fails to apply with Bacon and Zutano. There’s a Bacon tree in my San Jose neighborhood that produces consistently every year. Either their reasoning is not applicable to San Jose(due to it being much warmer than Santa Cruz County) or there is something specific to Bacon and Zutano that’s letting them thrive despite them being B types.

Also saw a mature Fuerte tree in a different part of San Jose (Evergreen). The owner said that it does alternate bear. But not as bad. 400 a year, 50 the next year. It never has years with zero production.

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Fuerte was introduced as a pollen source for the original Hass. However it is no longer needed with newer cultivars of the Hass produce grade.

The A and B type distinction is important for young trees in climates where all blossoms open on the same day. As the trees mature this occurs over a several day period, providing more opportunities for pollination.

Some avocado cultivar specimens have been observed to reverse their A, B tendency with maturity depending on climate. Stewart is one example.

There are also advanced cultivars in the Hass grade which blossom A & B simultaneously in ~60/40 ratio. The need for two different trees only arises with older cultivars which unfortunately still dominate the retail nursery offerings. Part of this is due to consumer confusion between the original Hass and the Hass grade cultivars sold in produce stores and utilized by restaurants. Many commercial orchards top-worked their trees years ago, although there are a couple here locally who have been too lazy to do so.

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It might be no longer needed for that purpose, but the OP of this thread says Fuerte is one of their favorite avocados, and many many other people share that opinion, so there’s still a good reason to grow Fuerte (for its own fruit), if not as a commercial pollenizer.

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In my opinion, Fuerte beats Hass hands down when it comes to nuttiness and complexity. It also ripens in 6 months and produces fruit in the Winter. Hass takes 16 months to ripen on the tree. It also takes salinity and cold weather much better than Hass.

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This might be true in your climate when comparing Fuerte to the original Hass. However, 70 years ago Fuerte was considered inferior to the original Hass when grown in the southern CA (esp. northern San Diego county) climate.

And yet, there seem to be tons of people who think the opposite is (and has always been) true, as Greg Alder has written about:

I used to think that I was alone in still finding the Fuerte a notch tastier compared to all of the other excellent avocados available in the year 2020. Yet I continue to meet people like Jan, the farmer from South Africa, who have eaten many kinds of avocados and also still find the taste of Fuerte unsurpassed. Writes Gary Bender in Avocado Production in California, “The Fuerte is still thought by many in the avocado industry to be the best tasting.”

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I believe Hass won due it it being less alternate bearing and more compact and having a longer hang time. Peak Fuerte season is between Nov- Feb. While Hass can hang from March to September. Fuerte was the leading cultivar for the better part of the century. Many avocado connoisseurs rate it much higher than Hass. Even the ones in Socal.

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By Hass, I meant Lamb, GEM and the like. We have our microclimates. North San Jose by the bay is zone 10A. There used to be Citrus orchards here. Here is the last surviving one.

https://www.villageharvest.org/blog/2020-north-san-jose-giant-orange-orchard-recap

Branham Lane is way down south. Far from the Bay. Gets like 5 degrees colder on average.
And many avocado growers in the "Socal Avocado growers " group on Facebook rate it higher than Hass. So its not just me. Greg Alder , who is also from Socal rates it way better than anything he’s tasted. Go to timestamp 3:08 in this video

These are old cultivars.

GEM isnt. Compared to the rest. And so what if they are old ? We are talking about Fuerte vs Hass like cultivars in terms of taste. Not old vs new.

Proof is in the pudding I guess. They get commercial yields of really delicious oranges here :). Orange County doesnt have any orange orchards left. But San Jose does. I am talking about commercial farmers here. You won’t see apricot groves here. They are further inland where you get a good amount of chill.

A

As @swincher quoted, and i re-quote…this opinion about Fuerte being the best in terms of taste is shared by farmers too. Consider reading everything before you type out your response :slight_smile:

"I used to think that I was alone in still finding the Fuerte a notch tastier compared to all of the other excellent avocados available in the year 2020. Yet I continue to meet people like Jan, the farmer from South Africa, who have eaten many kinds of avocados and also still find the taste of Fuerte unsurpassed. Writes Gary Bender in Avocado Production in California, “The Fuerte is still thought by many in the avocado industry to be the best tasting.”

@californication
I can understand someone having a preference for one fruit flavor over another. After all, I know some folks who feel perfectly ripe peaches are sour and will not eat peaches, period. And I do appreciate that the Fuerte is the earliest ripening and for your tastes the best quality avocado that can be grown at your site. But your claim that Fuerte is generally the best available avocado does not match my experience. For example, consider the lower price paid by packing houses for Fuerte in comparison to other cultivars since inception. Consider also what is taught about avocado grades by culinary institutes. So I think you should enjoy those Fuertes more and over-generalize about them less.

@californication thanks for the comparative information about San Jose and other cultivars. I would be curious to know what the temperatures are when you see B cultivars set fruit in N Cal. My hypothesis is that it is probably when things are warming up? April?

In the hopes that these observations will help someone troubleshoot Fuerte production… Today was the first day this year that Fuerte was in female stage at all. So its bloom from late November to now was exclusively male, the entire day… and actually, even today it was male until later in the afternoon. The nice thing about Fuerte though is that it keeps trying. It is often in bloom nearly half the year. I have a colleague at work who has a mature Fuerte tree. She lives closer to the coast. Her tree is always loaded. I wonder if in areas where it is not as cold at night, Fuerte sets better.

The traditional view is that the switch to female stage flowers is driven by daylight and time of day, but I do not see that where I am. It seems to be temperature. When it is cold, it “aint” switching. And then, typically in April, it begins to behave according to dogma (female stage in the afternoon). The high was 75 today and the low was 50 at night. That is typical of what I have read, it does not set well when it is colder than that. Fuerte might be famously cold hardy in its origin story but it does not seem to set fruit when it is cold.

I hope for a good crop but there are ants all over the tree, taking nectar from the flowers. This not only robs the flowers of the attraction to bees, they also have potential to harass the bees. I did set out bait when I realized the problem recently. I had noticed a similar issue with my cherries and ridding the ants did seem to help pollination/production/bee density. It is just anecdote but something to at least consider for those in marginal areas for Fuerte production.

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