Phenotypic and genotypic characterization of six selected provenances of Jatropha curcas Linn. planted in San Pablo City, Laguna, Philippines

Jatropha curcas Linn. is a multipurpose shrub that has acquired economic significance for its seed oil that can be converted to biodiesel. Six selected provenances from the Philippines were planted in Barangay [village] Santa Maria Magdalena, San Pablo City, Laguna to determine their phenotypic and genotypic characteristics and correlations of growth and seed traits as bases for identifying the best for diesel production. Results showed there was no significant difference among the provenances in root collar diameter and number of secondary branches (P greater than 0.05). Palawan provenance was significantly different from other provenances having the highest mean root collar diameter (8.39 cm) while General Santos provenance had the highest mean number of secondary branches (6.20). There was also significant difference in height and root collar diameter during dry and wet seasons, with significantly higher values during the wet season. The highest variability was found in the number of secondary branches. However, there was no significant difference in number of seeds, seed weight and crude fat content among the provenances. Correlation analyses showed height was strongly correlated with root collar diameter (r=0.84). There was a very strong correlation between number of seeds and seed weight per tree (r=0.90), between seed weight and crude fat content per tree (r=0.65), and between number of seeds and crude fat content per tree (r=0.64). Genotypic characterization using microsattelites (14 RST-SSR and 6SSR) indicated there was height level of genetic within the six provenances. The pooled gene diversity (He) was 0.56 observed heterozygosity (Ho) was 0.34 and polymorphism information content was 0.52. The maximum gene diversity (He), using the EST-SSR markers, was recorded from Palawan provenance (0.67) followed by General Santos and Catanauan provenances at both 0.65 He. Palawan provenance also registered the highest He of 0.41 together with Catanauan provenance using SSR. Analysis, of the 14 EST-SSR showed Palawan provenance had also the highest polymorphism information content of 0.62. The Mantel test for correlation between the morphological/phenotypic traits and genetic/molecular data revealed a very weak correlation (r=0.000314). Based on these results, Palawan provenance appeared to be the best among the six Jatropha curcas provenances for planting particularly in areas similar in environmental conditions to San Pablo City, Laguna.