Carotenoides y características morfológicas en cabezuelas de muestras Mexicanas de Tagetes erecta L.

Carotenoids and morphological evaluation of flower heads of Tagetes erecta L. from Mexican germplasm is presented for the first time. Twenty four randomly selected plants from different accessions, two additional accessions with orange flower head selected in situ, and two groups of ligule powder from 400 accessions of orange color were considered for analyzing carotenoids; 62 accessions were used to evaluate morphological traits. RAMAN technique for carotenoids from ligule powder of 28 samples revealed the following carotenoid concentrations: very low (≤ 4 g kg-1), low (4.1 to 8 g kg^-1), medium (8.1 to 12 g kg^-1), high (12.1 to 16 g kg^-1) and very high (> 16 g kg^-1). The highest carotenoid concentration was registered in orange colored samples. Variation was observed for diameter and fresh weight of flower head (3.8 to 9.7 cm; 2.3 to 17.2 g), ligule (1.5 g to 13.4 g) and receptacule (0.8 g to 5.4 g) fresh weight, and for the ligule/receptacule ratio (1.1 to 3.5).