WI: 'Papuan Rice' Domesticated?

[SinghSong]

A little thing I previously brought up in my last post on the AHC/PC: Could New Guinea believably be the most populous island on Earth? thread (which I would've liked to hear back from @Jared about, but c'est la vie)- there are 19 recognized species of rice in the Orzya genus, of which 6 (including Orzya rufipogon, the closest evolutionary relation and likeliest progenitor of Oryza sativa), are native to New Guinea.

And whilst the dominant New Guinean rice species may also be the most divergent from Oryza sativa (to the extent where crosses between it and them are near-impossible to accomplish), the species of the Oryza ridleyi complex (constituted of the O. longiglumis and O. ridleyi species, both of which are indigenous to New Guinea, along with the other islands east of the Weber Line) offer higher yields and larger grains even in their wild, uncultivated state than Oryza barthii (the progenitor of African rice, Oryza glaberrima), without O. barthii's tendency for its seedheads to shatter, and being similarly hardier, more pest-resistant and low-labour than Asian rice.

And both these species are also relatively unique, among those members of the rice family which produce edible grains in relative abundance, in so far as they prefer moderate to deep shade; growing readily in the understoreys of peat swamp forests and flooded freshwater rainforest thickets. This is in stark contrast to the two species of rice which were historically cultivated IOTL, O. sativa and O. barthii; both of which require at least six to eight hours of full sunlight per day, which necessitated the labor and maintenance-intensive practice of clearing forests to create suitably open rice paddies, and still renders make them incapable of providing decent harvests any more than 45 degrees north or south of the equator, as is the case with African and Asian cultivated species of rice).

So then, let's say that ITTL, Oryza ridleyi, aka 'Papuan rice' gets domesticated and starts being grown (either on New Guinea, or one of the Moluccas/'Spice Islands'- where its characteristics would have allowed it to be readily grown and harvested even in the shade of the nutmeg and clove trees) c.3,000 years ago; coinciding with the Austronesian peoples' migration through Maritime Southeast Asia to settle in the area, and their introduction of pigs and dogs, as well as the first domestication of O. barthii/'African rice' in the inland delta of the Upper Niger River in present-day Mali.

How much larger a population might the region be able to support as a result, and how might the balance of power be altered? And if/when this third domesticated rice species does inevitably spread beyond this region ITTL, as a domesticated rice species which requires no more sunlight than cabbages, spinach, broccoli, carrots or beets do (thus theoretically allowing it to be grown in far cloudier and more overcast environments, as well as those farther from the equator, provided they're sufficiently warm and wet), how much of an impact might its potential introduction, adoption, and cultivation have across the world?

 

[Roger II]

well THIS could be interesting.

 

[Ganesha]

How well does OTL rice grow in New Guinea today? From what I can see they barely grow any at all. This is a very interesting scenario; thanks for sharing it!

Cheers,
Ganesha

 

[SinghSong]

How well does OTL rice grow in New Guinea today? From what I can see they barely grow any at all. This is a very interesting scenario; thanks for sharing it!

Cheers,
Ganesha

It purportedly grows very well in the wild; especially in wetter, more humid conditions. Just hasn't ever really been domesticated, since the indigenous tribes favored other crops instead, and those who introduced rice cultivation to the wider region (incl. islands in the Moluccas that indisputably 'reached a higher level of civilization', like Halmahera, Ternate, Tidore, Ambon, Seram and Buru, where the rice was also endemic), the Makassar of Sulawesi, had also acquired their own cultivars of wetland japonica rice from mainland Asia, which had been introduced to them as well as to the natives of Java and Bali c.2,500-3,000 yrs ago by way of Mindanao.
https://upload.wikimedia.org/wikipedia/commons/9/9c/Likely_routes_of_early_rice_transfer,_and_possible_language_family_homelands_(archaeological_sites_in_China_and_SE_Asia_shown).png

IOTL, the Austronesian Bugis' ancestors settled on Sulawesi around 2500 BC, from South China and Taiwan, and over the next couple of thousand years, proceeded to take over the island in its entirety from its original native inhabitants, the 'Toaleans' (the DNA of whom's been sequenced, with about half of their genetic makeup shared with present-day Indigenous Australians and people in New Guinea and the Western Pacific, and the other half coming from a previously unknown divergent human lineage that branched off approximately 37,000 years ago, with the closest affinity to the Aeta and Andamanese; and similarly to the Aeta, having a higher level of Denisovan ancestry than any other peoples in the world), who they rendered extinct in the process. A large part of this was attributed to the Austronesians' superior package of crops (incl. japonica rice, millet and adlay) and domesticates (incl. pigs, dogs and water buffalo), as well as their slash-and-burn agricultural practices and superior technologies.

But it's becoming increasingly apparent that the civilization struggle between the proto-Makassar and Toaleans was a far closer-run and more protracted affair than previously thought, enduring for over a millennia. The Toaleans appear to have had an established trade network of their own, pre-dating the Austronesians' arrival in southern Sulawesi, which extended across the Moluccas as far as Timor and the western coast of New Guinea, as well as several crops and domesticates of their own; the Sulawesi Pig (the only other pig species to have been domesticated apart from the wild boar) appears to have been domesticated by them c.7-6,000 years ago, preceding the Austronesians' introduction of pigs from China by about 2,000-3,000 years, and unconfirmed records of the localized survival of the last Stegodons, purportedly as recently as c.4,100 yrs ago on Flores and southern Sulawesi, revolve around the accounts of their semi-domestication by the Toalean culture, only to be ultimately rendered extinct predominantly due to the destruction of their habitats by the slash-and-burn agricultural policies introduced by the Austronesians, clearing the forests to make way for rice paddies (not sure how plausible or realistic this may be, but rule-of-cool).

Archaeological evidence also indicates that it was they, and not the Austronesians, who first introduced several other plants from the Moluccas, Timor and New Guinea to the Sunda islands, including candlenuts, breadfruit, jackfruit and coconuts (the latter two of which appear to have been domesticated by themselves first), with the later forest-dwelling Austronesians of southern Sulawesi having acquired these crops from them. ITTL, you'd expect the Toaleans to be the first in the Sunda Islands to acquire O. ridleyi, and disseminate the crop westwards. If they did adopt it as a staple crop, and it did confer comparable or superior yields to the contemporary basal javanica variant of japonica rice (fairly plausible, with the rice diversification into Maritime Southeast Asia only taking place between 2,500 and 1,500 yrs ago IOTL), then there's every chance that they could come out on top over the ancestral Buginese and Makassar peoples' common ancestors ITTL, whose growth and eventual rise to total dominance was supported by a rapid increase in wet Asian rice cultivation.

IOTL, a genetic study concluded that the origin of the Sama-Bajau people was here, in southern Sulawesi, with their ethnogenesis estimated to have dated back to around the 4th century CE by an admixture event between the Bugis people and the Papuans who would've been the last remnants of the Toalean culture; with this study suggesting that the Sama moved to eastern Borneo at around the 11th century CE, and then towards northern Borneo and the southern Philippines at around the 13th to 14th centuries CE, hypothesizing that they were driven to migrate during the increase of influence and trading activities of the Srivijaya Empire. Genetically, the Sama-Bajau are highly diverse, indicating heavy admixture with the locals, along with language and cultural adoption by coastal groups in all the areas they settled. But just last year, in 2021, a genetic study discovered a unique genetic signal among the Sama-Bajau of the Philippines and Indonesia, dubbed the "Sama ancestry"; which matches that 'previously unknown divergent human lineage' found in the sequenced DNA of the Toalean hunter-gatherer 17-18yo female from c.5,200 BCE, and scientifically verifies that the 'Sea Gypsies' are the the sole extant group who can trace their lineage back to the Toalean culture.

So then, if the Toalean culture did adopt O. ridleyi ITTL in this era, with the crop enabling them to hold their own against or even come out on top over the Austronesians, then things could get even more interesting, especially if they continued to expand their seafaring trade network and embark upon successful overseas explorations to the same extent (or to an even greater extent in some directions, particularly to the south and south-east) that OTL's Makassar did. With this rice species' preference for moderate or deep shade, it'd have enabled the rainforests to be conversed and maintained, rather than being cleared via slash-and-burn agriculture to make way for open rice paddies; and in so doing, would have potentially enabled the last surviving stegodons, along with other endemic extinct species like the south Sulawesi babirusas and anoas, to survive and be at least semi-domesticated ITTL, as well as the historically endemic population of the island's original apex predators, Komodo dragons (with South Sulawesi thought to have been their primary habitat, and the Komodo dragons there estimated to have been c.30-50% larger than the extant Komodo dragon populations on Flores and Komodo).

I'm currently revising a 'Papualand'/New Guinean civilization building ATL I'd started writing on The Other Place back in the day, which starts to diverge from OTL c.5,000yrs ago, and the Toaleans of Southern Sulawesi are set to play a big role; with their maritime trade network having been established over a millennia before that of the Kingdom of Gowa IOTL (which was purportedly founded c.1300 CE, in a marriage between a local woman and a chieftain of the Sama-Bajau, with the early agrarian chiefdom of Gowa having previously had no direct access to the coastline nor interest in maritime trade), and thus providing the launchpad to propel them to the stage of kingdom-building similarly earlier than the Sultanate of Gowa did, as contemporaries of the Kutai Martadipura Kingdom and Salakanagara Kingdoms. Combining all these factors together, Sulawesi's set to wind up with a peak projected population density ITTL somewhere between those of OTL's Mindanao & Luzon (equating to a peak population of 47.2-86.7M); with New Guinea's peak population density set to be somewhere between those of OTL's Sulawesi & Sumatra (equating to a peak population of 82.9-97M), and mainland Australia's (with TTL's equivalent of Makassar contact coming over a millennia earlier, accompanied by widespread colonial coastal settlement, vaguely paralleling that of pre-colonial Timor IOTL) set to be comparable to that of OTL's New Guinea (equating to a peak population of c.106-115M). All of which is set to make Greater Sahul/'Papualand' (incl. the islands east of the Wallace Line) a far bigger deal ITTL than it was/is IOTL...

 

[JesterBL]

One item I feel should be clarified is that there are upland rice landraces of o. sativa- they just aren't particularly productive (rule of thumb from what I remember- 50% production compared to paddies, although modern breeding has some very promising results). Paddies also assist in weed control- do we know how o. ridleyi would compare to o. sativa in terms of growth rates against weeds? If it's shade tolerant but still requires extensive weeding then it has less comparative advantage against o. sativa.

 

[SinghSong]

One item I feel should be clarified is that there are upland rice landraces of o. sativa- they just aren't particularly productive (rule of thumb from what I remember- 50% production compared to paddies, although modern breeding has some very promising results). Paddies also assist in weed control- do we know how o. ridleyi would compare to o. sativa in terms of growth rates against weeds? If it's shade tolerant but still requires extensive weeding then it has less comparative advantage against o. sativa.

So far as I understand it, from my investigation into the crop, O. ridelyi's actually significantly better than O. sativa in that regard, with a significantly greater ability to compete with weeds, comparable to that of O. glaberrima. It's also hardier and more pest-resistant (though in the case of the later, O sativa's something of a victim of its own success in that regard; in an ATL where O. ridleyi was more widely cultivated, of course you'd inevitably get more pests emerging to specialize in feeding on it eventually).

The members of the O. ridelyi complex (incl. O. schlechteri and O. longiglumis, which can be hybridized with one another- and also loosely including O. coarctata) have been identified as having the largest genome size of any rice species, possessing various agronomically important genes; they're the most resistant rice species to bacterial blight, stem borer and blast, as well as being the best adapted to aerobic soils- which actually makes it moderately more productive in upland regions' more aerobic soils as it is in the lowlands, with this rice species found in several areas of the New Guinean Highlands, such as the Upper Sepik River and around the Chambri Lakes. And they're also the most tolerant of salinity by far- with this being especially true of the most loosely related member of the complex, O. coarctata.

This wild rice species is native to the coastal regions of the Indian subcontinent (incl. Bangladesh, Myanmar & Pakistan) where it's eked out a niche for itself in the lunar tidal regions where it's submerged with saline seawater every 12 hours. O. coarctata's unique among wild rice species insofar as it possesses 'salt hairs', outgrowths of the epidermis that increase their number under high salinity and secrete excessive salt, just like other halophyte grasses (including Nipa, the only wild halophyte grain IOTL, which was harvested and consumed by the Cocopah of the Colorado River basin). Thanks to this, and to other adaptations including decreased root-to-shoot translocation and increased compartmentalization in the vacuole, it possesses extreme salt and submergence tolerance, O. coarctata's the only halophyte rice species, capable of tolerating an upper salinity limit for long-term irrigation of 30-40ppt salt.

Whilst O. ridleyi's salinity tolerance is nowhere near that, it's still good enough to grow in brackish water, tolerating concentrations of up to 10-12ppt. And while O. coarctata's more distantly related to O. ridleyi than any other members of the complex, its genome type is still close enough to be counted as an outlying part of the complex (or vice versa), and thus hypothetically be borderline capable of hybridizing with O. ridelyi in the wild. Which, if/when it happened ITTL (most likely, shortly after 'Papuan rice' gets introduced to the Indian subcontinent), would give rise to a hybrid 'Papuan Tidal Rice' variety, which should hypothetically be capable of being grown using saltwater agriculture (comparable to the hybrid varieties currently being developed between O. coarctata & O. sativa, only facilitated via intensive genetic engineering efforts)- which would undoubtedly be a massive game-changer, not just for India, but the entire world. Whilst O. ridleyi's not the absolute best at coping with heat stress (with African rice being marginally superior in this regard), the decline in rice production caused by heat stress to it's still fairly small, and less than that suffered by O. sativa. But there are still a few other aspects where O. sativa does have a comparative advantage over it.

It's even worse than African rice at coping with cold stress, with low temperatures negatively affecting their growth and development to an extreme degree, stymieing any prospects of growing it outside of the tropics in spite of its shade tolerance (for at least a millennia or so at any rate, however long it takes for a Ridleyi japonica equivalent to arise, similarly adapted to colder and more temperate climates in a process driven by domestication). And ironically, it's also poorer than either Asian or African rice at tolerating flooding and waterlogging (being wholly reliant on the 'escape strategy', whereby shoot elongation is stimulated by progressive flooding, keeping leaves in contact with the air and escaping the increasing water levels; if it can't manage this, and gets completely submerged to the extent it can't elongate its leaves fast enough, then rather than being able to fall back upon the 'quiscient strategy' whereby hypoxia reduces elongation, represses carbohydrate degradation and stimulates anaerobic metabolism, it'll simply die), as well as being drought intolerant.