Phytochemical traits in crop plants reflect both genetic characteristics and environmental conditions and could serve as useful markers for germplasm evaluation. This study compared the phytochemical profiles of purple and white Dioscorea alata L. tubers cultivated in Yogyakarta, Indonesia. Proximate analysis, Fourier Transform Infrared Spectroscopy (FTIR), and Gas Chromatography-Mass Spectrometry (GC-MS) were methods used to characterize biochemical composition in raw and steamed tubers. The results revealed clear phytochemical differences between the two tuber types, with purple tubers showing relatively higher carbohydrate levels and greatly abundant phenolic-related compounds. FTIR spectra indicated functional groups associated with carbohydrates, phenolics, and lipid derivatives, while the GC-MS analysis identified phenolic compounds and fatty acid ethyl esters as major constituents. The agroclimatic data describe the environmental conditions during tuber development and provide contextual background for interpreting the observed phytochemical profiles. These findings highlight the potential use of phytochemical traits as biochemical markers for D. alata germplasm characterization and will support the selection of nutritionally valuable yam varieties in breeding programs.

Keywords: Dioscorea alata, phytochemical variation, agroclimatic influence, germplasm characterization, FTIR, GC-MS, crop improvement

Key findings: Purple and white Dioscorea alata L. exhibited distinct agroclimatic-driven phytochemical variations, with purple tubers consistently containing higher levels of phenolic compounds and fatty acid ethyl esters than white tubers. Favorable agroclimatic conditions, particularly stable temperatures and high solar radiation, enhanced secondary metabolite accumulation, supporting the use of these phytochemical traits as biochemical markers for D. alata germplasm evaluation and varietal selection.