There were dozens of other worthwhile hybrids produced, with beautiful skin and pulp colors, and for those of us who like "reticulata" flavors, delicious.  Many also had profitable seasonalities in-between other Annonaceous crops.  These were Atemoyas (sugar-apple x cherimoya;  and cherimoya x sugar-apple) using 'Red Sugar' and 'Kampong Mauve' and 'M-2' and 'Purple' sugar-apples; Temoylatas  (atemoya x reticulata); Cherilatas (cherimoya x reticulata); and atemoya x 'M-1' hybrids ('M-1' = one of the "Giant Mexican Sugar-Apples"). 

[Mother plant should always be listed first.  Annona reticulata generally refused to mother seeds fathered by squamosa or cherimola or their hybrids.]

Low productivity, gritty and/or rubbery texture, some persons' dislike for "reticulata" flavors and aromas, high maintenance requirements, and long seed-to-fruit juvenility periods, were the stumbling blocks.

Some types of crosses produced only worthless offspring, at least among the few dozen plants of each which were evaluated:  atemoya back-crossed to green sugar-apple to get greater productivity, and atemoya back-crossed to pretty sugar-apples for skin color.

Viable plants of many other types of hybrids were produced which involved the above species and Ilama (ilama = Annona diversifolia), Cawesh (or Cahuex =Annona scleroderma), and the dwarf Annona globiflora.   None of these ripened any fruit.  Ilama and globiflora hybrids died out under poor growing conditions.  Cawesh hybrids grew large and hadn't flowerd yet after a dozen or so years of waiting, so were cut down to make way for mango hybrids.

At the time we thought the main issues for the plants were

1) "Green LeafHoppers" = Potato LeafHoppers
2) the arrival of Annona seedborers
3) pollenation issues
4) unevenness of cultural attention ("Waxing hot and cold"), some years great care, other years near zero care with weeds higher than the trees.

In retrospect, as atemoya / cherimoya, sugar-apple nutritional requirements had not yet been established --- the Australians later did a good job of that --- our trees were seriously deficient in Zinc and Boron, and probably deficient in Calcium.  If this had not been the case, plant viability, hardiness, precocity, pollination, fruit set, fruit size and color and flavor and texture, would all have been far better.

Hybrids still in existence that probably are worth having, but are not currently available, include the temoylatas '4---5' [pronounced "Four Dash Five"] and '47---18'.  [The first number was the row in the experimental field;  the second number was plant position in the row.]

Crafon Clift topworked one of his Asimina hybrids onto a large Guanabanus montanus (Annona montana) at the Kampong, south of Miami.  The graft grew 4-5 feet, maybe more, and lasted at least two years.  Eventually something happened to it, got shaded out or snapped in a hurricane, perhaps.

Note that this was a large tree used as a rootstock, with the tree allowed to keep most of its own branches, fully leafed out all year.  Such a rootstock wouldn't "care" if one small branch were leafless a couple of months.

Theoretically a fully-leafed-out scion would "care" if the roots under it went dormant;  but maybe growth regulators sent down from healthy leaves would prevent the roots from going dormant.  Or maybe a normally-evergreen scion, knocked leafless by bad weather, would be awakened better in the spring by roots used to not being fed for months.

It sounds worth trying.  I have no idea if the true Annonas (Sugar-Apples, Cherimoyas, Custard-Apples, etc.) would be graft compatible with Asimina.

DMSO  BY ITSELF is not very scary.  One of our late past presidents of the Palm Beach County Rare Fruit Council used to buy it by the gallon and drink it for his back and leg pains.  He did this for years.

It is said that two pest control applicators in Broward County mixed DMSO with a pesticide that they were very used to working with--- and both promptly died from it.
It can work too well.

You need to obtain a spray suit of some material rated for DMSO--- I don't know about it.   Or just don't mix it with anything that you don't want to raise your blood concentration of.

I have seen someone run his fingers over the male flower, check to see pollen sticking on his fingers, then very lightly running his hand over a female flower.   I didn't check back to see if it actually worked.

I'm one of those who pants well into the easements.   

I also know that the foraging rights of wayfarers have been codified at least since the Books of Moshé--- but with convenience stores every mile or two I don't see the need in suburbs.   

I still yell, "Hey!  That's not your tree, is it?!"  "This isn't a public park!"  "I work Hard to take care of that tree so that I and my family and friends can eat those fruits."  "Why are you destroying my food so that you can have green fruit fights on the street?!"  "If you like those fruits, ask your daddy to plant a tree of it in your yard--- then watch it all the time so that nobody steals the fruits!"

On the other hand, I do do often field requests for "star fruits."  "I will pick some for you.  Meet me by the street." 

On New Year's Day I took about a dozen carambolas to each of 20 neighboring houses:  a few each of 'Sri Kembangan' , 'Kari' , 'Missy', 'HEW-1',  'B-10.'

El Bumpo and Selma and Spain are ones that I remember liking some twenty-five years ago.

It is great to know that Rollinia deliciosa (mucosa) is so cold-hardy.  I have long known that it is nothing like soursop in that regard.  And I knew that large Rollinia trees in Boynton Beach (at Zill's) survived the freezes of 1984 and 1987, about 28F for an hour or so.

As to Argentina, Rollinia deliciosa/mucosa is not listed there--- not surprizing, as even Iguazú Falls, in the northernmost tip of Argentina, has a record low of -4.9C.

The Annonacea listed by Catálogo de las Plantas Vasculares de la Argentina:  Annona nutans, Rollinia emarginata, Rollinia rugulosa, Rollinia salicifolia, and Xylopia brasiliensis.

When you visit the lovely plantations at Akil, be sure to visit Oxkutzcab near by, and look for Vivero Marín, which probably was the source of a lot of those trees.

Bigger with MORE seeds and more flavor, when hand-pollinated with unadulterated pollen.  No talcum, etc.  I gather pollen early evening and use same evening.

The elaborate flower-removal-to-gather-pollen techniques, accomodate governmental 8AM-4:30PM strict employee schedules.

Very impressive.

Salt man,
I hope your "weird wasps" aren't Annona Seed Borers.

I don't remember the new growth's color of the Guapomó.  This fruit from the Salacia genus of the Hippocrateaceae family was introduced from Bolívia to Florida in 1988 by Crafton Clift.  The stiff opposite leaves and opposite branches and fruit all resemble mangosteens and bacurís, but are not related.  I have one from seed of the one that fruited at Zill's back in the late 1990's--- very slow growing with my neglect to water it.  I haven't seen new growth for a long time, and my old photo album done for Dr Al Will's class doesn't show new growth.