SAO PAULO- Farmers in Brazil's key center-south region collected an estimated 20% of their second corn crop, up from 12% in the week before, as dry weather allowed harvesting to advance, consultancy AgRural said on Monday.

Due to planting delays, however, the pace of the work is behind that of last year, when 35% of the second corn crop had been harvested in the region, AgRural said a statement.

Farmers in Mato Grosso have harvested the most second corn fields, with the work in Goi?s, S?o Paulo and Minas Gerais also advancing, according to the consultancy.

In Paran? and Mato Grosso do Sul, harvesting kicked off slowly on some farms. But with only a small portion of the crop actually ready, farmers in those states remained focused on evaluating the losses caused by frost at the end of June and early July.

In both Paran? and Mato Grosso do Sul, expected rainfall in the second half of July may worsen corn quality problems, AgRural said.

AgRural forecasts Brazilian farmers will harvest 59.1 million tonnes of the second corn crop, down from 75.1 million tonnes last season.

(Reporting by Ana Mano Editing by Paul Simao) ((ana.mano@thomsonreuters.com; Tel: +55-11-5644-7704; Mob: +55-119-4470-4529; Reuters Messaging: ana.mano.thomsonreuters.com@reuters.net))