(Corrects story originally published on April 9 to say measure expires, instead of takes effect, on July 31 in bullet points, paragraph 2)
* Non-Mercosur wheat quota rises to 2 mln tonnes
* Zero cotton tariff to ease inter-harvest shortfall
* Rule changes expire on July 31
* Most new supply seen coming from U.S.
SAO PAULO, April 9 (Reuters) - Brazil will double its wheat-import quota for purchases outside a regional free trade bloc and cut to zero its tariff on cotton imports to help industries expected to be hurt by high prices and low stocks.
The country's foreign trade commission (Camex) on Tuesday bumped the wheat quota up to 2 million tonnes from 1 million tonnes. The zero tariff on cotton applies to purchases of up to 80,000 tonnes. Both decisions expire on July 31.
Prices of wheat, cotton and other crops generally rise as stocks fall in the inter-harvest period that comes with the advent of the Southern Hemisphere winter beginning in June. Production from farms in the Mercosur free trade bloc, comprising Argentina, Brazil, Paraguay, Uruguay and Venezuela, is below normal this year, raising concerns stocks will be especially hard hit.
In the first eight days of April the price of wheat in Brazil was 50 percent above the average April price a year ago, according to a report from the University of Sao Paulo's Advanced Center for Applied Economic Studies (Cepea).
On Monday wheat traded at $7.125 a bushel in Chicago, up around 7 percent from a week earlier.
The quota increase comes a month after Camex cut the tariff on wheat to zero from 10 percent with the warning that it could raise the quota if Argentine production appeared to be insufficient to cover Brazil's needs.
The wheat harvest in Argentina, Brazil's main supplier, fell 29 percent to 11 million tonnes in 2013 compared with 15.5 million in 2012, according to the U.S. Department of Agriculture (USDA).
Brazil has already begun to buy wheat from outside Mercosur, primarily from the United States, from where most of Brazil's new supply is likely to come, market participants said.
The new cotton import tariff is aimed at helping garment and other textile industries avoid shortfalls of cotton fiber during the inter-harvest period of May, June and July, Camex said in a statement. (Reporting by Roberto Samora and Tiago Pariz; Writing by Jeb Blount; Editing by Joseph Radford)