A RAPD Genetic Map of Saccharum officinarum

Saccharum officinarum L. is the major contributing species to modern sugarcane varieties. It is a polyploid where 2 n = 80, although the basic chromosome number and level of ploidy have not been conclusively determined. A genetic map in S. officinarum could benefit breeding programs through marker‐assisted selection and could provide information about the genetic structure of sugarcane. The objective of this research was to develop a genetic linkage map by means of random amplified polymorphic DNA (RAPD) single‐dose markers in S. offcinarum . The map was constructed with 84 F 1 progeny from the cross ‘La Purple’ ( S. officinarurn ) × ‘Molokai 5829’ ( S. robustum Brandes and Jeswiet ex Grassl.). Single‐dose markers should segregate in a 1:1 fashion in the progeny of this cross. Primers were first screened in the parental genotypes, and those revealing polymorphisms were then tested in six progeny selected at random to identify putative single‐dose markers. All resulting markers were then tested in 84 progeny and those showing a 1:1 segregation pattern were considered single‐dose markers and were used for mapping. Among 279 singledose markers identified from initital screening with 1840 primers, 161 markers were linked in 50 linkage groups with a minimum LOD of 5.0 and a maximum recombination value of 0.28. The detection of 12 repulsion linkages suggested the occurrence of limited preferential chromosome pairing in this species. Linkage of eyespot susceptibility to a RAPD marker identified an additional linkage group and indicated that linkages identified in this map could potentially be used for marker‐assisted selection.