Published online by Cambridge University Press: 20 January 2012
Introduction. In Malaysia, Limau Madu (Citrusreticulata Blanco; Citrus suhuiensis Hort.ex Tanaka) is commercially cultivated for local consumption. Itis a loose-peel mandarin with fruits that are spherical in shapewith shiny green or greenish yellow peel. In Malaysia, Limau Maduis vegetatively propagated, thus it is presumed to exhibit minimalvariability. In our study, the genetic variability and genetic relatednessamong cultivated samples collected from different states in Malaysiawere assessed using Simple Sequence Repeat (SSR) primers. Materialsand methods. Thirty pairs of SSR primers derived from Citrusunshiu were screened and 22 SSR primer pairs were utilizedto assess genetic variability and relatedness among 118 cultivatedsamples. Results and discussion. The percentage of SSR transferabilityfrom C. unshiu to C. reticulata (LimauMadu) was 73.33%, which indicated that the primer sequences flankingsimple sequence repeats were conserved among these Citrus species.Most SSR loci revealed a large excess of heterozygotes. In our study,low allelic diversity was shown, with an average of 5.227 allelesper locus. Polymorphic information content (PIC) ranged from 0.048to 0.674. Based on UPGMA clustering analysis, four groups were identifiedfrom these citrus genotypes with a mean genetic distance of 0.170. Lowgenetic variability within species was probably due to vegetativepropagation or inability to detect differences among samples usingthese primers.