Influence of mother plant age on the in vitro propagation of Agave cupreata Trel. & A. Berger via organogenesis

Agave cupreata Trel. & A. Berger is an endemic species from southern Mexico with cultural and economic value due to its use in mezcal production. The increasing global demand for mezcal has led to intense overexploitation, resulting in a marked decline in its natural populations. Micropropagation represents a viable alternative for the multiplication and conservation of this species. This study evaluated the effects of mother plant age (6, 12, 18, and 24 months) on in vitro organogenic capacity. The morphological parameters of the mother plants were characterized, and the effects of age and regeneration cycle on shoot production were analyzed. Results showed that age was directly associated with morphological development: six-month-old plants had the lowest number of leaves (5.20 ± 0.82), height (9.77 ± 1.05 cm), and stem diameter (0.80 ± 0.12 cm), followed by plants aged 12 (12.20 ± 1.38 leaves, 11.26 ± 0.95 cm, 1.23 ± 0.18 cm), 18 (13.83 ± 1.83 leaves, 13.83 ± 0.89 cm, 1.80 ± 0.24 cm), and 24 months (19.00 ± 3.46 leaves, 24.73 ± 3.28 cm, 2.90 ± 0.41 cm). Contamination was highest in explants from 24-month-old plants. Nevertheless, individual variability among seed-derived mother plants proved to be a key factor determining regenerative capacity, with plants showing very low (≤ 10 shoots), low (11–30), medium (31–50), high (51–80), and very high (> 80) productivity levels regardless of age during the induction stage. These findings highlight the role of mother plants in the micropropagation of A. cupreata for its conservation.