* Petrobras shares slide 6% as CEO resists pressure to resign * Mexican peso lags regional peers this week * Chile"s peso sole weekly gainer in Latam (Adds details, updates prices) By Susan Mathew and Ambar Warrick Feb 19 (Reuters) - Brazil"s Bovespa slid on Friday as oil major Petrobras slumped on concerns about top management, while Mexico"s peso lagged its peers for the week as the effects of a deep freeze in the neighboring state of Texas disrupted activity in the country. Shares of Petroleo Brasileiro slid more than 6%, on course for their worst session in 11 months as its chief executive resisted pressure from Brazil"s President Jair Bolsonaro to resign following tensions over rising fuel prices. While Bolsonaro has expressed sympathy for truckers threatening to strike over higher diesel prices, Castello Branco said their complaints were not the company"s problem and insisted that Petrobras will set prices independent of political pressure. Underperforming most regional peers, the Bovespa index slipped 0.8%, putting it on track for a 1% weekly decline. Brazil"s real, meanwhile rose 0.6% against a softer dollar, but as is the case with most emerging market currencies, looked to post declines on the week as rising U.S. Treasury yields squeezed risk assets. Brazil"s Congress will next week analyze a constitutional amendment that aims to revive emergency cash transfers to millions, while examining cuts elsewhere to stop from breaching a spending cap. The country"s stretched fiscal status has weighed on interest in Brazil"s financial markets. Mexico"s peso weakened 1% as investors worried about a hit to the country"s manufacturing sector. More companies halted production in Mexico due to power blackouts caused by Texas limiting fuel supply owing to the cold wave there. The peso was set to lose about 2.7% this week, much more than its regional peers. Meanwhile, Reuters exclusively reported that Mexico"s government is planning to inject a total of about $5 billion into state oil company Petroleos Mexicanos (Pemex) this year. But market experts were less than enthused. "This is in line with our expectations as well as the long-standing government approach of offering ad hoc assistance to Pemex without fixing the core problems," said Citigroup strategists. Concerns about the weight of bailing out the firm on Mexico"s economy have led to downgrades by rating agencies of both the firm and Mexico"s sovereign credit rating. Copper prices rallied and top producer Chile"s peso firmed to six-week highs. The currency was the sole weekly gainer among its peers as expectations of a recovery in industrial demand drove up copper prices. Key Latin American stock indexes and currencies: Latest Daily % change MSCI Emerging Markets 1428.25 0.22 MSCI LatAm 2388.66 0.32 Brazil Bovespa 118179.22 -0.86 Mexico IPC 44896.37 0.87 Chile IPSA 4599.84 1.8 Argentina MerVal 51008.71 -1.579 Colombia COLCAP 1349.86 -0.28 Currencies Latest Daily % change Brazil real 5.4088 0.58 Mexico peso 20.5003 -1.03 Chile peso 708 0.34 Colombia peso 3569.3 -0.69 Peru sol 3.6517 -0.02 Argentina peso 89.1400 -0.09 (interbank) (Reporting by Susan Mathew in Bengaluru; editing by Jonathan Oatis)