LENGTH POLYMORPHISM AND HOMOLOGIES OF MICROSATELLITES IN SEVERAL CUCURBITACEAE SPECIES

The objectives of this research were to assess (1) the degree of Simpl e Sequence Repeats (SSR) DNA length polymorphism in melon (Cucumis mel o L.) and other species within the Cucurbitaceae family and (2) the po ssibility of utilizing SSRs flanking primers from single species to ot her genera or species of Cucurbitaceae. Five melon (CT/GA)(n) SSRs wer e isolated from a genomic library. Two cucumber (Cucumis sativus L.) S SRs were detected through a search of DNA sequence databases, one cont ained a (CT)(8) repeat, the other a (AT)(13) repeat. The seven SSRs we re used to test a diverse sample of Cucurbitaceae, including 8 melon, 11 cucumber, 5 squash, 1 pumpkin, and 3 watermelon genotypes. Five of the seven SSRs detected length polymorphism among the 8 melon genotype s. PCR amplification revealed between three and five length variants ( alleles) for each SSR locus, with gene diversity values ranging from 0 .53 to 0.75. Codominant segregation of the alleles among F-2 progeny w as demonstrated for each of the five SSR loci. Four of the seven SSRs detected polymorphism among the 11 cucumber genotypes, with gene diver sity values ranging between 0.18 and 0.64. Primers specific to SSRs of C. melo and C. sativus also amplified DNA extracted from genotypes be longing to other genera of the Cucurbitaceae family.