POTATO GERMPLASM ENHANCEMENT FOR RESISTANCE TO BIOTIC STRESSES AT CIP- CONVENTIONAL AND BIOTECHNOLOGY-ASSISTED APPROACHES USING A WIDE-RANGE OF SOLANUM SPECIES

Potato;genetic improvement has been facilitated using new knowledge of potato reproductive biology and new techniques. Many wild diploid spe cies as well as landrace cultivars have been used in breeding at the d iploid level, a strategy which is supported by 1) 2n gametes and 2) ha ploids from tetraploid cultivars. Different categories of wild species which have been under-utilized are now being exploited further in mor e systematic enhancement programmes using semi-conventional and biotec hnological methods. Molecular maps of the potato genome are used activ ely to achieve marker-assisted introgression and improved selection am ong the germplasm collections to facilitate the use of valuable wild g enetic resources. As an alternative method to incorporate a high level of resistance, genetic engineering has been employed to facilitate th e initial breeding process using various gene constructs for controlli ng major biotic stresses in the world.