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In this paper, we characterize a temperature dependence in longan (Dimocarpus longan Lour.) cultivars using the high annealing temperature random-amplified polymorphic DNA (HAT-RAPD) methodology. This form of genomic analysis allows a random sampling of the complete genome to provide information about phenotypic traits of interest. Using a set of 18 unique decamer primers, polymorphic bands ranging from 100 to 2500 bp were examined for 14 longan varieties from which banding patterns of interest were selected for conversion to the more reproducible and robust sequence characterized amplified region (SCAR) markers. In particular, one SCAR marker produced an electrophoresis banding pattern which could distinguish between longan varieties requiring a sustained interval at low temperatures for fruit production vs. those that do not. This band was composed of a nucleotide region 275 bases in length (DQ539047) in which the initial 90 nucleotides were >85 % identical to the 12-oxophytodienoic acid (OPDA) reductase gene. OPDA is an immediate precursor to jasmonic acid which has been described as the Ômaster switchÕ for lipid-derived environmental signalling to factors such as flowering and osmotic stress. The possible involvement of the jamonic acid signalling pathway could explain the recent success of potassium chlorate to induce off-season flowering and fruit formation.

Abstract:To create a molecular marker characterization for twenty species of Ficus, eight decamer primers were used to randomly amplify these species genomic DNA producing a total of 172 distinct polymorphic band patterns. One band was chosen to be converted into the more robust sequence characterized amplified region (SCAR) marker format to provide a unique molecular marker characterization for the variety of Ficus hirta. This technique for species identification and characterization provides a morphologically independent test to verify relatedness and provide species information particularly for cases where such identification was previously untenable such as in the case of morphologically indistinguishable plant cuttings.