Temperature effects on meristem differentiation and flowering date in tuberose (Agave amica L.)

Tuberose is an ornamental plant of economic importance produced worldwide due to the elegant shape and fragrant flowers. Despite its commercial importance, one of the limitations of tuberose production is control of flowering time, which has not been determined at present. In our research, the flowering time has been evaluated in corms of Agave amica cv. Double, during two production cycles (2017 and 2018) using different times of storage of the corms (4, 5, 6 and 7 weeks) at variable temperatures (4 °C, 12 °C, 27 °C, RT). Also, we studied the development of the corms to determine which changes occur in the meristem during floral transition and how the flower quality is affected. The results showed that meristematic differentiation occurred 30-45 days after establishment (DAE) in both culture cycles, although there was no temperature treatment that clearly affected the meristem growth. However, some floral characters were affected, the earliest sprouting occurred in the treatment of six and seven weeks of storage at 27 °C at 20 DAE in 2017 and 10 DAE in 2018, respectively. In addition, the shortest time to flowering occurred in the treatment of seven weeks of storage at 27 °C at 79 days in 2017 and at 100.6 days in 2018, a value that is 30 days earlier than that obtained with the treatments of six weeks of storage at 12 °C, which delayed meristem transition, sprouting and flowering time. In contrast, treatments at 4 °C and GA3 were not statically different from the control in both years.