Domesticating grasses

There are some six or seven hundred genera of grasses, and God only knows how many species. Of these, something like six or seven are eaten as cereals. Is there some botanical reason why these are the only grains widely eaten, or could any grass be bred into food, so a PoD of 9999 BC ATL may have krikittle, moophes and chisanno instead of rice, corn and wheat?
 
I suppose it would be possible if the prehistoric folks were willing to take the time to do it. According to the ever-popular "Guns, Germs, and Steel", corn went through a long process of being selectively bred to be larger, from a really tiny cob to the large 'ears' we have today. Wheat and barley were selected early on because they have seeds larger than other grasses. I suppose it would depend on how 'easy' it is to domesticate them too; you have to get grains to do the entirely illogical process of all ripening at the same time and not scattering their seeds in the process. Apparently, wheat, barley, and rice were fairly 'easy' in this process, other grasses may not be.
 
With thousands of years you could domesticate any of the grasses. The problem is that there's no incentive to do so. The vast majority are only marginally useful and would be extremely difficult to grow in any kind of controlled setting for the first few hundred years. The wild forms of the grains we eat today had the advantage of large easily harvested seeds that made gathering and eating them worthwhile and growing fairly easy. One of the current theories is that people gathered the largest most easily harvested grains and ate and replanted those leading to each generation being easier and larger. Most grasses are going to be an absolute nightmare to harvest and really no use once you have. Far more energy would be expended in raising it than you'd ever get from eating it.
 
I suppose it would be possible if the prehistoric folks were willing to take the time to do it. According to the ever-popular "Guns, Germs, and Steel", corn went through a long process of being selectively bred to be larger, from a really tiny cob to the large 'ears' we have today. Wheat and barley were selected early on because they have seeds larger than other grasses. I suppose it would depend on how 'easy' it is to domesticate them too; you have to get grains to do the entirely illogical process of all ripening at the same time and not scattering their seeds in the process. Apparently, wheat, barley, and rice were fairly 'easy' in this process, other grasses may not be.
Don't forget that grasses are in many ways inferior to other types of staple crops, especially in certain climates.

For example, a native to the American Tropics, peach palm not only more productive than rice or maize but also gives a greater variety of products than any grass (as do many palms): Starch and flour from the fruit, excellent wood for making tools and houses, cooking oil and even its fibres are now being considered for use in plastic composites.

Or, to give another example, look at a more well-known plant - the banana. A native of New Guinea, the banana plant not only provides a source of a staple food but also provides a soft and silky fibre: Indeed, banana "silk" is so soft as to now be becoming very popular with vegans.

For that matter, amaranth and quinoa are complete proteins (which I greatly enjoy on a regular basis), unlike any grass; both also can both be used to make vegetable oils and both have leaves that can be used as green vegetables, unlike any grass I know of.
 
There are some six or seven hundred genera of grasses, and God only knows how many species. Of these, something like six or seven are eaten as cereals. Is there some botanical reason why these are the only grains widely eaten, or could any grass be bred into food, so a PoD of 9999 BC ATL may have krikittle, moophes and chisanno instead of rice, corn and wheat?

Yes. Because these were the grasses that were:

(a) easiest to domesticate; and
(b) give the highest yield.

Wheat and barley were easiest to domesticate, as were (in different climates) plants like sorghum in Africa.

Once a plant is domesticated, it tends to inhibit the domestication of closely related plants unless it offers some special advantage. Why bother going to the effort of domesticating a wheat relative when you have an already domesticated wheat right here? So there's a real first-mover advantage for domesticated grasses.

However, there's more to the story than that. Thanks to modern genetics, when can now domesticate just about any grass we choose (with perhaps the occasional specialised exception). But that doesn't mean that the plants will yield any better than existing crops.

The existing domesticates have thousands of years of selective breeding to increase their yield, and in many cases they already were the best-yielding crops to start with (e.g. wheat, barley). So a new domesticate can't really compete with the existing major staple crops, except sometimes in niche roles.

Mind you, it has been possible historically for some new domesticates to replace older domesticates, if their yield is higher. The classic example is rice. In early East Asian farming, millets (small-seeded grains) were the early domesticates. But they were largely replaced by wheat and rice as those crops gave higher yield.

There are also examples of domesticated cereals which were abandoned entirely (in both North and South America) with the arrival of better-yielding domesticates.
 
There are some six or seven hundred genera of grasses, and God only knows how many species. Of these, something like six or seven are eaten as cereals. Is there some botanical reason why these are the only grains widely eaten, or could any grass be bred into food, so a PoD of 9999 BC ATL may have krikittle, moophes and chisanno instead of rice, corn and wheat?

There are multiple species of wheat domesticated.Triticum, Rye.Secale, Oats.Avena, Barley.Hodeum, rice.Oryza, several millets (Wiki lists 10 genera of millets), mais.Zea, teff (dont remember the genus).

Wild rice.Zizannia is harvested historically, but is only now being cultivated.

In addition, you have sugarcane and multiple sorghums, although not as grain. And multiple bamboos, although they are only secondarily used as food.

So, its a BIT richer than you suggest.
 
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