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United States Department of Agriculture

Agricultural Research Service

Research Project: MANAGEMENT OF GENETIC RESOURCES FOR VITIS, PRUNUS, JUGLANS, FICUS, OLEA, PISTACIA, PUNICA, DIOSPYROS, ACTINIDIA, AND MORUS

Location: National Clonal Germplasm Rep - Tree Fruit & Nut Crops & Grapes

Title: Simple Sequence Repeats in Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai]

Authors
item Jarret, Robert
item Merrich, L. - UNIV OF MAINE - ECOLOGY
item Holms, T. - LINKAGE GENETICS
item Evans, J. - LINKAGE GENETICS
item Aradhya, Mallikarjuna

Submitted to: Genome
Publication Type: Popular Publication
Publication Acceptance Date: March 4, 1997
Publication Date: August 1, 1997
Citation: Jarret, R.L., Merrich, L.C., Holms, T., Evans, J., Aradhya, M.K. 1997. Simple Sequence Repeats in Watermelon [Citrullus lanatus (Thumb.) Matsum. & Nakai]. Genome, 40:433-441.

Interpretive Summary: Simple sequence repeat length polymorphisms were utilized to examine genetic relatedness among accessions of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai). A size-fractionated TaqI genomic library was screened for the occurrence of dimer and trimer simple sequence repeats (SSRs). A total of 96 (0.53%) SSR-bearing clones were identified and the inserts from 50 of these were sequenced. The dinucleotide repeats (CT), and (GA), accounted for 82% of the SSRs sequenced. PCR primer pairs flanking seven SSR loci were used to amplify SSRs from 32 morphologically variable watermelon genotypes from Africa, Europe, Asia, and Mexico and a single accession of Citrullus colocynthis from Chad. Cluster analysis of SSR length polymorphisms delineated 4 groups at the 25% level of genetic similarity. The largest group contained C. lanatus var. lanatus accessions. The second largest group contained only wild and cultivated "citron3'-type or C. lanatus var. citroides accessions. The third group contained an accession tentatively identified as C. lanatus var. lanatus but which perhaps is a hybrid between C. lanatus var. lanatus and C. lanatus var. citroides. The fourth group consisted of a single accession identified as C. colocynthis. "EgusiW-type watermelons from Nigeria grouped with C. lanatus var. lanatus. The use of SSRs for watermelon germplasm characterization and genetic diversity studies is discussed.

Technical Abstract: Simple sequence repeat length polymorphisms were utilized to examine genetic relatedness among accessions of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai). A size-fractionated TaqI genomic library was screened for the occurrence of dimer and trimer simple sequence repeats (SSRs). A total of 96 (0.53%) SSR-bearing clones were identified and the inserts from 50 of these were sequenced. The dinucleotide repeats (CT), and (GA), accounted for 82% of the SSRs sequenced. PCR primer pairs flanking seven SSR loci were used to amplify SSRs from 32 morphologically variable watermelon genotypes from Africa, Europe, Asia, and Mexico and a single accession of Citrullus colocynthis from Chad. Cluster analysis of SSR length polymorphisms delineated 4 groups at the 25% level of genetic similarity. The largest group contained C. lanatus var. lanatus accessions. The second largest group contained only wild and cultivated "citron3'-type or C. lanatus var. citroides accessions. The third group contained an accession tentatively identified as C. lanatus var. lanatus but which perhaps is a hybrid between C. lanatus var. lanatus and C. lanatus var. citroides. The fourth group consisted of a single accession identified as C. colocynthis. "EgusiW-type watermelons from Nigeria grouped with C. lanatus var. lanatus. The use of SSRs for watermelon germplasm characterization and genetic diversity studies is discussed.

Last Modified: 7/25/2014
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