BEYOND CLIMATE: EXPLORING FLOWERING CYCLES IN ACROCOMIA THROUGH PHOTOPERIOD

Acrocomia, an oilseed palm genus endemic to the subhumid tropics of South and Central America, produces multiple inflorescences that flower sequentially during the transition from dry to rainy season and well into the rainy season. Since acrocomia is monoecious and protogynous, cross-pollination predominates. However, variations in flowering patterns and their environmental triggers remain poorly understood, yet their understanding is crucial for optimizing mating opportunities and yield formation in commercial production. Therefore, this study evaluated the flowering patterns - onset, midpoint, peak, and frequency - of six acrocomia accessions in the BAG-Macaúba germplasm collection at the Federal University of Viçosa, Brazil. The flowering onset and progress of 31 palms were monitored weekly during the flowering seasons of 2019 to 2021. We used circular statistics to assess seasonal flowering patterns, and moving window analysis to explore Spearman's rank correlations between flowering peak, climate, and photoperiod factors with 54 half-month lags (2.5 years before the flowering peak). A total of 382 inflorescences were recorded over three years: 120 in 2019, 166 in 2020, and 96 in 2021. Flowering generally began in September and continued until January, peaking in late November. Although inflorescence counts varied considerably among accessions and across years, the flowering patterns—onset, midpoint, and duration—remained consistent. Contrary to expectations, flowering peaks did not correlate with climate but exhibited significant associations with the winter solstice (negative correlation), the summer solstice (positive correlation), and sunrise/sunset shifts around the solstices. These findings on climate-independent flowering synchrony show the potential to achieve a predictiple flowering cycle in commercial production, thereby optimizing yield stability, resource management and labor efficiency.