Submitted to: Potato Association of America Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/1/1997
Publication Date: N/A
Technical Abstract: Genetic resistance to Columbia root-knot nematode (Meloidogyne chitwoodi Golden et al.) was introduced to a potato breeding population by fusion of resistant Solanum bulbocastanum with tetraploid cultivated potato. Subsequently, 55 restriction fragment length polymorphisms (RFLP) and 112 random amplified polymorphic DNA (RAPD) markers polymorphic between S. bulbocastanum and cultivated potato were assigned chromosomal locations an mapped. Nematode resistance was localized to a single location on chromosome 11. The pattern of transmission of a subset of RAPD markers spanning all twelve linkage groups was determined in BC2 and BC3 populations. It was found that 44 percent and 25.5 percent of the alien genome remained on average in the BC2 and BC3. There were, however, frequent deviations from the average on a progeny and genetic marker basis. A surplus of progeny with a low proportion of alien genome was found in the eBC3. Markers on chromosome 11 closely linked to nematode resistance were scored in BC3 and BC4 populations together with resistance response. The RFLP marker "cd17" from tomato co-segregated with resistance 98 and 96 percent of the time in the BC3 and BC4 populations. Confirmation was obtained of an inversion of potato marker order with respect to tomato on the upper arm of chromosome 11. RFLP and RAPD marker technologies provide an efficient way of analyzing the dynamics of genome partitioning during introgression and can be used as selection aids for closely linked traits. The difficulties of obtaining reliable nematode resistance data argue persuasively that use of genetic markers as selection aids may be more time efficient and cost effective than screening for resistance.