The stage is set for a battle of nerves Saturday between an upbeat Congress and a defensive Janata Dal-Secular (JD-S) in the first phase of Karnataka election where the fortunes of about 950 candidates will be decided by 17.3 million voters in 89 constituencies across 11 southern districts.

A traditional bastion of the Congress and the JD-S and a hostile territory for the Bharatiya Janata Party (BJP), a strong contender for power, the historically known old Mysore region holds key to the prospects of forming the new government this month-end.

In the 2004 assembly election, of the 89 assembly segments, the JD-S captured 36 while the Congress managed to win in 28 seats. The BJP sprung a surprise by bagging 15 seats, including five from Bangalore.

The presence of the Bahujan Samaj Party (BSP) in a big way this time spells trouble for the Congress and JD-S as it is set to play spoilsport by cornering a chunk of votes from Scheduled Castes, Scheduled Tribes and backward classes.

In the last election, the Congress claimed to have narrowly lost in about 20 constituencies in the region due to BSP.

Although the number of constituencies remains the same even after delimitation, he demographic profile of the electorate and the rigid caste combination in a predominant Vokkaliga region will define the voting patterns in semi-urban and rural areas.

The Congress has fielded candidates keeping in view the caste arithmetic in each constituency and the winnability criteria.

In contrast, the battle for urban votes in India's Silicon hub Bangalore, where the number of constituencies has shot up by a whopping 75 percent to 28 from 16 in the 224-member assembly after delimitation, is being waged on issues such as infrastructure development, civic amenities, stability and good governance.

'The first phase of the poll will be a testing time for the JD-S as well as Congress, with BJP and BSP snapping on their heels. In the absence of winnable candidates for BJP in many constituencies, barring in Mysore and Bangalore, the Congress and JD-S are betting on their traditional voters. Both the parties are, however, wary of BSP making a difference in winning and losing,' political analyst Trilochan Shastri told IANS.

A fractured verdict in 2004 and the collapse of three coalition governments in a span of 42 months leading to an early poll after a spell of President's Rule have been a blessing in disguise for the Congress to seek a vote on the stability plank.

The party has also flagged various socio-economic schemes of Prime Minister Manmohan Singh's government, including the farm loan-waiver scheme, the National Rural Employment Guarantee Act, the National Rural Health Mission and the Bharat Nirman for Rural Infrastructure Development to woo the electorate in the countryside.

In urban areas, especially Bangalore, it has highlighted the failure of the JD-S-BJP government in improving the city's infrastructure and completing several civic projects.

On the other hand, the JD-S, BJP and BSP have made soaring food prices a major campaign issue to pin down Congress.

With the return of former chief minister S.M. Krishna to state politics after a three-year stint as Maharashtra governor to spearhead the Congress campaign, the party is counting on his IT-savvy image in urban areas.

Although stalwarts like Siddaramaiah, M.P. Prakash and P.G.R. Sindhia deserted the JD-S owing to differences with party supreme and former prime minister H.D. Deve Gowda, Gowda's sons - former chief minister H.D. Kumaraswamy and H.D. Revenna - are tirelessly racing across the region to retain their hold in the home turf.

Making the 'betrayal' by the JD-S over power transfer, terrorism and price rise its main campaign themes, the BJP is hoping to increase its tally in the region in a bid to form its first government in the state or emerge as the single largest party -- as in 2004.

The second and third phases of the elections will take place May 16 and May 22. The votes will be counted Mayh 25.