Genetic Linkage Map of Cassava (Manihot esculenta Crantz) based on SSR and SNP Markers

Cassava is an important tuber crop grown mainly in the tropical and sub-tropical regions. The crop is a source of calories for over 500 million people worldwide. To improve the crop, genetic improvement through breeding is necessary. The use of simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) are the powerful tools to generate a linkage map in cassava. F1 mapping population from 96 1089A and TME 117 was developed with 180 progenies. To produce the linkage map, parental lines were screened with over 200 SSR markers and the polymorphic markers were used on the progenies. Of 717 SNP markers used, 347 were polymorphic. 253 markers comprising of 248 SNP and 5 SSR markers were used. 18 linkage groups were drawn with an average of 14 markers on each chromosome and the average marker distance of 6.5cM. The total length of the map was 1,493cM. SNP markers are many and could be easily used to construct a genetic linkage map compared with SSR markers.