Oct. 16 (Bloomberg) -- Voters in Botswana cast their ballots in an election that will probably extend the ruling party’s more than four-decade hold on power, even as the country faces its worst economic crisis.

The Botswana Democratic Party is expected to benefit from the fragmented opposition’s failure to capitalize on an economic recession triggered by plunging demand for diamonds, the mainstay of the economy. A BDP victory will automatically lead to the retention of Ian Khama, 56, as the southern African nation’s president.

“The BDP will win because it has the advantage of incumbency,” David Sebudubudu, a political scientist at the University of Botswana in Gaborone, said in a phone interview today from the city. “The opposition has also failed to challenge the BDP as a united force so they have gone into this election divided.”

Botswana is the world’s largest producer of diamonds, which have helped the BDP transform the country from a poor, cattle- ranging society into the success story of Africa with a per capita gross domestic product close to that of Mexico and Argentina. The party also presided over this year’s slump, when the closure of the diamond mines because of tumbling global demand will knock about 10.3 percent off GDP, according to the International Monetary Fund.

Queues at Dawn

Voters gathered at polling stations before dawn and queues were still evident by midday in and around Gaborone, where temperatures reached at least 32 Celsius (90 Fahrenheit). Some who had waited for more than four hours to vote complained about the slowness of the process, which involves marking two separate ballot papers for parliamentary and council candidates.

“We’ve been here since before the polling station opened, but we haven’t moved,” Mkosho Mpete, an 86-year-old resident of Mabalane, said in an interview under the shade of a syringa tree at Mabalane Primary School. “The process is too slow for our age. We wish it could be faster so we could go home and rest.”

Khama cast his vote in Serowe, about 250 kilometers (150 miles) northeast of Gaborone, and called for a strong voter turnout, according to images broadcast on Botswana Television, the state-owned broadcaster.

The BDP has the support of 44.4 percent of the electorate, compared with 27.4 percent for the opposition Botswana Congress Party and 20.7 percent for the Botswana National Front, according to the results of a survey conducted by Probe Market Intelligence published in the Botswana Gazette on Oct. 14. It didn’t provide a margin of error.

Prosperity

“We have seen economic prosperity, civil liberties and good governance because of what the BDP stands for as a party,” Esther Norris, a BDP member, said while waiting to vote at a polling station in Block 8 on the outskirts of Gaborone. “If you look at the division within the opposition it reflects disorganization that will take the country nowhere.”

Botswana’s per capita GDP rose to $13,900 last year from $13,400 two years earlier, according to the U.S. Central Intelligence Agency’s Web site. The international watchdog Transparency International ranks Botswana as the least corrupt nation in Africa, ahead of countries such as Italy and South Korea.

The country’s economy will contract this year after Debswana Diamond Co., the joint venture between Johannesburg- based De Beers and Botswana’s government, suspended operations in February as the worst global recession since World War II hurt jewelry sales. The company resumed production at most of the operations in April.

‘Massive Shock’

“Botswana has never really had such a massive shock to its economy,” said Jan Duvenage, Africa analyst at Johannesburg- based Standard Bank Group Ltd., the continent’s biggest lender. “This has brought home the importance of diversifying the economy. It should be the main focus of the incoming administration.”

Mining generates about a third of economic output in Botswana and diamonds account for about 70 percent of exports. The government has previously announced measures to diversify the economy, including developing “high-end” tourism destinations, expanding its power-generation industry and establishing an international financial-services center in Gaborone.

Diversification is needed to help find work for the almost one in four people who are unemployed, according to the IMF.

Polling stations in the nation of 1.8 million people closed at 7 p.m. local time and final results are scheduled to be announced tomorrow.

To contact the reporters on this story: Paul Richardson in Johannesburg at pmrichardson@bloomberg.net; Jerry Bungu in Gaborone via Johannesburg at pmrichardson@bloomberg.net.

Last Updated: October 16, 2009 16:29 EDT