Eight Cultivars Analyzed
Using the RADP-PCR method, the genetic diversity of 8 orange cultivars, 4 mandarin cultivars and 3 pummelo cultivars was analysed. Most of these citrus fruits were found to be genetically highly diverse. The cultivars are probably the result of natural crossing.
Twenty-four random primers were used in RADP reaction with DNA genomes from these15 citrus cultivars. CTR 2, SPA 19, DER 10 and LY F8 were identified as primers to be used for detailed analysis.
Thirty-three random amplified DNA fragments were obtained with 4 primers from genomes of oranges, mandarins and pummelos. The size of the DNA ranged from 0.4 to 2.3 kb.
Characteristics of the Dna
Of the 33 DNA fragments, 25 (80%) were monomorphic and present only in a single orange cultivar. The percentage of random amplified polymorphic DNA of the orange cultivar was only 20. No RADP was obtained with LY F8 and DER 10 primers.
Thus, it was concluded that orange cultivars are genetically highly diverse, with a low homologous coefficient (0.5946-0.8095).
Cultivars of mandarin and pummelo were also found to be genetically highly diverse. The percentage of monomorphic DNA fragment of mandarin was 54, and that of pummelo was 75.
The RADP-PCR technique was found to be effective for identifying the origin of crosses, and for the selection of parents for heterosis with high quality.
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