Miranda, Marlon N. July 2022, CLONAL PROPAGATION OF TRUE-TOTYPE SOUR TAMARIND (Tamarindus indica LU.) USING DIFFERENT ROOTING HORMONES, MORPHOLOGICAL CHARACTERIZATION AND DNA-BASED ANALYSIS) OF PSAU SOUR TAMARIND ACCESSIONS. BACHELOR OF SCIENCE IN) BIOLOGY. Pampanga State Agricultural University Adviser: Mr. Jacob Anderson C, Sanchez, M. Sc. Sour tamarind is a valuable commodity particularly in the culinary arts of the Philippines. This study aimed to distinguish and acquire measurements on the vegetative and generative growth of different sour tamarind lines collected from the established orchard of Pampanga State Agricultural University (PSAU). It also intended to produce a propagated true-to-type seedling and perform a genomic characterization using DNA analysis and Bioinformatics. Morphological characterization and yield performance results showed that PSAU Sour 2 is most viable for genetic improvement and cultivation. Clustering morphological data by running a Hierarchical Ascendant Analysis (HAC) revealed that PSAU Sour 2 was different from the other PSAU sour tamarind cultivars. Clonal propagation of sour tamarind through stem cuttings posed difficulties but was partially achieved under the ANAA rooting hormone treatment. Percentage survival was calculated, ANAA had 51.67% rate compared to the rooting gel with 0%. matK DNA primer exhibited 71.43% PCR success rate in comparison to rbcL with 0%. UPGMA method and Kimura 2-parameter model showed that PSAU Sour 2 formed a monophyletic relationship with the tamarind cultivar of Cabanatuan Sour 1. Both formed a paraphyletic relationship in the tamarind cultivar of PSAU Sour 3 which is closely related with the tamarind accessions of Africa. Nucleotide analysis using MEGA 11 revealed the following differences: PSAU Sour 3 nucleotide sequences indicated a very close relationship with other sour tamarind cultivars primarily from Thailand and Africa. Cabanatuan Sour 1 and PSAU Sour 2 were most likely similar; however, at specific site 622 and 623 PSAU Sour 2 exhibited a variation. Hence, despite the closeness of PSAU Sour 2 to Cabanatuan Sour 1, there is genetic evidence proving genetic variations between each other. In conclusion, PSAU Sour 2 contained unique traits that weren't present among the other sour tamarind cultivars within and outside the country.