* Muslim Brotherhood boycott strengthened grip of tribal candidates
* Results show most candidates gain with tribal backing
By Suleiman Al-Khalidi
AMMAN, Jan 24 (Reuters) - Pro-government tribal candidates strengthened their grip on Jordan's parliament after Wednesday's general election, boycotted as rigged by the Muslim Brotherhood-led opposition, according to preliminary results.
State television on Thursday listed most of the 150 seats contested, saying they were won by independents, candidates with limited political agendas who rely on family and tribal allegiances rather than party backing.
The Islamic Action Front, the Muslim Brotherhood's political wing in Jordan and the country's largest opposition party, shunned the election because it said the electoral law was designed to curb its influence.
The front said last year it would boycott the polls after the tribal-dominated parliament passed a electoral law that magnified the clout of native Jordanian constituencies at the expense of cities, which are home to many citizens of Palestinian origin and which tend to be Islamist strongholds.
Turnout for Wednesday's vote was 56 percent of the country's 2.3 million registered voters.
The Islamists say only a fraction of Jordan's eligible voters cast their ballots and that another 2.4 million eligible voters did not register to vote on Wednesday, Jordan's first parliamentary election since the Arab uprisings.
Islamists draw more support in the densely populated cities, where most of the country's 7 million population live, and voting is more along political and ideological lines.
In the major cities, including the capital, all strongholds of the country's most organised political grouping, turnout figures averaged around 40 percent. In sparsely populated rural and Bedouin areas it was more than 70 percent.
Officials say the elections were a milestone in democratic reforms espoused by King Abdullah and that the opposition had misjudged the popular mood, saying many voters had shunned the opposition's boycott call.
Tribalism has been on the rise as a political element in Jordan, blunting the emergence of national parties and curbing the influence of Islamists.