Question: What type of rice might Native Americans have extensively cultivated?
About the article "Rice", section "Caribbean and Latin America".

Candidate passages:
Cultivated extensively. 
Patna rice, a variety of the species "Oryza sativa", and one of the varieties of long-grain white rice, is extensively cultivated in the Indo-gangetic plains, in and around Patna, capital of Bihar state, India.
Patna rice is known for its elongated kernel with grain length greater than 6 mm, and has been used as staple food by the local people for thousands of years.
Sometimes, Patna rice is also called "Parimal" rice locally.
This mildly flavoured rice comes from the Bihar region of the Ganges plains.
It has a robust, long and narrow, opaque grain that keeps its shape well for curries.
Basmati rice is closely related to the Patna rice but has a stronger aroma.
The Mughal chronicler Abul Fazal who collected the various types of rice grown in the Gangetic belt has described the rice cultivated in Patna in glowing terms.
William Fullarton of Skeldon UK made his fortune by dealing in Patna rice.
He chose Patna as the name of the coal-miners' hamlet he built in East Ayrshire, Scotland.
Since most of the rice sold in Europe came from this region at one time, the term "Patna rice" also sometimes loosely designates any long-grain aromatic rice.
Another example of long-grain rice is American long-grain rice which include Carolina rice.
It is believed that Patna rice was the first type of rice cultivated in America [http://www.dailybread.co.uk/food/rice.htm], and acquired the name Carolina rice.
The seeds of Patna rice were taken to America, grown in Carolina and exported to Britain before the American Civil War.
Thus the term Carolina rice is also sometimes used to denote this variety of rice. 
In bushels per acre, except cotton in kilograms.
In Chientao or Yenki Manchu district the Korean Colony extensively cultivated rice. 
Rice is not native to the Americas but was introduced to Latin America and the Caribbean by European colonizers at an early date with Spanish colonizers introducing Asian rice to Mexico in the 1520s at Veracruz and the Portuguese and their African slaves introducing it at about the same time to Colonial Brazil.
Recent scholarship suggests that enslaved Africans played an active role in the establishment of rice in the New World and that African rice was an important crop from an early period.
Varieties of rice and bean dishes that were a staple dish along the peoples of West Africa remained a staple among their descendants subjected to slavery in the Spanish New World colonies, Brazil and elsewhere in the Americas.
The Native Americans of what is now the Eastern United States may have practiced extensive agriculture with forms of wild rice.
In northern China, the Nanzhuangtou culture on the middle Yellow River around Hebei (–7700 BC) had grinding tools.
The Xinglongwa culture in eastern Inner Mongolia (–5400 BC) ate millet, possibly from agriculture.
The Dadiwan culture along the upper Yellow River (–5400 BC) also ate millet.
By the Yangshao culture (–3000 BC), the peoples of the Yellow River were growing millet extensively, along with some barley, rice, and vegetables; wove hemp and silk, which indicates some form of sericulture; but may have been limited to migratory slash and burn farming methods.
The Longshan culture (–2000 BC) displays more advanced sericulture and definite cities.
In southern China, the Pengtoushan culture on the Yangtze River (–6100 BC) has left rice farming tools at some locations, though not at the type site.
The Hemudu culture around Hangzhou Bay south of the Yangtze (–4500 BC) certainly cultivated rice.
The various people (such as Baiyue) who succeeded to these areas were later conquered and culturally assimilated by the northern Chinese dynasties during the historical period.
The Karuo culture (–2000 BC) may have introduced agriculture into Tibet, where they cultivated foxtail millet.