Patna, April 15 (IANS) Caste arithmetic will be put to test in Bihar when seven parliamentary constituencies in the state go to polls Thursday.

These elections are crucial for Bihar Chief Minister Nitish Kumar of the JD-U and his bete noire RJD chief Lalu Prasad with both vying for approval as the main player in Bihar politics and to emerge with an enhanced kitty.

For the Bharatiya Janata Party (BJP), the stakes are even higher as its prime ministerial candidate Narendra Modi hopes to get the mandate to form the next government at the Centre.

Nitish Kumar is fighting a solo battle with the aim to prove that he continues to matter in the state while Lalu Prasad aspires to a revival in these polls.

About 1.22 crore eligible voters will decide the political fate of 117 candidates in the fray in Buxar, Ara, Nalanda, Jehanabad, Munger, Patliputra and Patna Sahib. These seats are poised for triangular contests unlike last polls.

Among those prominent in the fray are actor-turned-politician Shatrughan Sinha -- popularly known as Bihari babu; former union home secretary R.K. Singh; Misa Bharti, daughter of Lalu Prasad; real estate baron Anil Kumar Sharma; former Bihar police chief Asish Ranjan Sinha; former minister Ashwani Kumar Choubey; and Rajiv Ranjan alias Lalan Singh, a friend of Nitish Kumar.

Star campaigners and candidates are talking of development, good governance, rule of law and fight against corruption -- but caste arithmetic will play a dominant role.

The BJP is confident of overwhelming support of the upper castes, particularly vocal landed Bhumihars who are known to influence politics in the state, and hopes to garner support of other backward castes (OBCs), extreme backward castes (EBCs), Dalit and Mahadalits, the poorest among Dalits -- thanks to its alliance with Lok Janashakti Party (LJP) of Ram Vilas Paswan and Rashtriya Lok Samata Party (RLSP) of Upendra Kushwaha.

BJP has fielded most of its candidates looking at the caste equation.

BJP candidate from Buxar, Ashwani Kumar Choubey, a Brahmin, is eyeing nearly 40 percent voters belonging to the upper caste, mainly Brahmins. BJP candidate R.K. Singh from Ara hopes to get a majority of his castemen - Rajputs - who have a strong presence.

Similarly, BJP candidate and sitting MP from Patna Sahib, Shatrughan Sinha is depending on his upper caste Kayastha voters, who are nearly four lakh-strong and supported him last time.

On the other hand, RJD-Congress candidates are depending heavily on the overwhelming support of the traditional caste support base of Yadavs, a section of EBCs, Mahadalits, Rajputs and Muslims.

In Patliputra, Lalu's daughter Misa Bharti is fighting a tough battle against two other Yadav candidates - BJP's Ram Kirpal Yadav and JD-U candidate and sitting MP Ranjan Prasad Yadav.

"In Patliputra, the fight is among three formidable Yadav candidates. Their caste votes will be divided. BJP is hopeful of the support of Bhumihars and other upper castes, while Lalu's daughter is eyeing support of other backward castes and Muslims and JD-U is sure of Kurmi, EBCs, Mahadalits and Muslims support," said Ranjiv, a political activisit.

Lalu has vigorously campaigned in Patliputra for his daughter and has addressed more than a dozen public meetings.

During campaigning, an AAP candidate was attacked and injured in Nalanda.

The outlawed CPI (Maoist) has given a call for boycott of the elections and threatened to disrupt the polls.

Security arrangements have been bolstered for the polls.

About 42,600 security personnel, including 152 companies of central para military forces, 74 companies of Bihar Military Police and 20,000 home guards would be deployed, Chief Secretary A.K. Sinha said.

Two of the constituencies that vote Thursday in the second phase of polling in the state are in Maoist-affected areas.