DOI: 10.36347/sajb.2021.v09i02.003

Pages: 29-35

Papaya (Carica papaya Linn.) is an important crop with high pro-vitamin A carotenoids content. In Nigeria, the major papaya fruit flesh colours observed is the yellow and red-fleshed varieties. To differentiate the yellow and red-fleshed papaya varieties, a study carried out to genetically delineate the yellow and red-fleshed papaya varieties to establish their phylogenetic relationship and varietal differences using molecular markers as a diagnostic tool. DNA was extracted from the young leaves of the yellow- and red-fleshed varieties at the Regional Centre for Biotechnology and Bioresources Research Centre, University of Port Harcourt with ZYMO Quick-DNA™ Plant/Seed Miniprep Kit. The gDNA quantity and concentration were measured using the Nanodrop 2000c spectrophotometer and Agarose gel electrophoresis. The gDNA samples were shipped to the International Institute of Tropical Agriculture (IITA) Bioscience Center, Ibadan, for amplification using the Ribulose-1, 5-biphosphate carboxylase (rbcL) primers and the amplicons were sequenced using the ABI3500 capillary electrophoresis sequencer. The DNA sequence file was saved in the Bioedit file with extension .ab1. The sequence was analyzed using the Molecular Evolutionary Genetics Analysis (MEGA) version 7.0.26 software, and aligned using the Basic Local Alignment Search Tool for nucleotide (BLASTN) 2.8.0 version of the National Center for Biotechnology Information (NCBI) database. The amplified DNA sequences of the two papaya varieties yielded 580 base pairs. The result of the taxonomy report generated from the sequences of the two papaya varieties matched 64 sequences of the members of the Caricaeae family, of which 21 sequences hits matched Carica papaya and 23 sequences hits matched the Vasconcella genus. The BLAST phylogenetic tree indicated that both papaya species were grouped together with Carica papaya cultivars in the NCBI database. Also, the sequences of the yellow-fleshed papaya (NKECHI_RBCL_6) and ..........