Johannesburg - Western Cape premier, Mr Hernus Kriel, the man tipped to succeed the National Party leader, Mr F. W. de Klerk, withdrew from the succession contest yesterday, Patrick Laurence reports. His decision to withdraw reflected a reluctance on his part to forfeit his power-base for the prestige of the party's leadership, and boosted the prospects of Mr Martinus Van Schalkwyk, the party executive director. Another potential candidate is Mr Kraai van Niekerk, who served as agriculture minister in Mr de Klerk's cabinet and, briefly, in the post-apartheid government of national unity.