Argentine soy prices track Chicago gains

* Soy prices in Rosario closed up at between 1,170 and 1,200 pesos per tonne ($273-$280), lifted by gains in the influential Chicago futures market, traders said. Soy closed at 1,184 pesos in the previous session.

* Trade volume swelled to 13,000 tonnes from the scant 3,500 tonnes a day earlier.

* Soybean futures on the Chicago Board of Trade ended firm on mounting concern about pockets of dryness in South American crop areas and spillover support from gains in soybeans.

* The La Nina weather phenomenon is expected to reduce rainfall in Argentina's main crop belt until at least mid-January, hitting corn and soy yields and preventing some plantings, forecasters said this week.

* In Rosario, soybeans for May 2012 delivery, priced in US dollars, closed up $5 at $270 per tonne.

Following is a list of grains and oilseed prices in Argentina's main ports. Values from the previous session are in parentheses. All figures listed are in pesos per tonne.