'Plant Breeding: Sustaining the Future' Abstracts of the XVIth EUCARPIA Congress, Edinburgh, Scotland, 10-14 September 2001 OPTIMAL SAMPLING STRATEGY AND CORE COLLECTION SIZE OF ANDEAN TETRAPLOID POTATO BASED ON ISOZYME DATA S. CHANDRA, Z. HUAMAN, S. HARI KRISHNA, R. ORTIZ IITA, Oyo Road, PMB 5320, Ibadan, Oyo State, Nigeria

Selection of an appropriate sampling strategy is an important prerequisite to establish core collections of appropriate size to adequately represent the genetic spectrum and maximally capture the genetic diversity in available crop collections. We developed a simulation approach to identify optimal sampling strategy and core collection size on Andean tetraploid potato. Five sampling strategies - constant, proportional (P), square root, and random (R) - were tested on isozyme data (9 loci with a total of 38 alleles) from 9396 accessions. A core collection of size n=600, selected using either the P or the R sampling strategy appears to be adequate because it represents, for both allozyme frequency and locus heterozygosity, the genetically refined entire collection (GREC). The GREC includes 1910 genetically distinct groups of accessions after using a sort and duplicate search algorithm in the 9396 accessions.