Floral Biology of Four Mangifera indica (Anacardiaceae) Cultivars

Understanding the variability of the floral biology of crops and the impact of abiotic factors that influence this variation can be used to inform conservation and management of their living germplasms. This study evaluated the floral characteristics, pollen germination, and flowering phenology of four commercial cultivars of Mangifera indica (‘Julie,’ ‘Keitt,’ ‘Kent,’ and ‘Tommy Atkins’) at the Juana Diaz Experimental Station (JDES) in Puerto Rico using quantitative and qualitative methods. Results show significant differences across cultivars in variables related to inflorescence size (width, length), architecture, flower production, and flower sex ratios. However, these differences were not necessarily consistent across years. Flowers of M. indica reflect color in the UV region, but these patterns are qualitatively different in ‘Keitt,’ which also shows qualitative differences between perfect flowers and staminate flowers using both UV and visible spectrum photos. Mangifera indica trees produce more sucrose than glucose and fructose, but different cultivars presented different sugar profiles based on the relative percentage of sugar contents. Pollen viability was high for all cultivars, but pollen germination exhibited an optimal temperature that varied depending on the cultivar. Likewise, for all cultivars, pollen from staminate flowers exhibited higher germination percentages compared to pollen from perfect flowers at temperatures above optimal values. But at temperatures below the optimal, they had a tendency for lower germination percentages relative to perfect flowers, although this pattern was only significant for ‘Kent.’ The results may have important implications for the management of mango cultivars, especially within the context of projected climate change. For pollen-germinating cultivars that are susceptible to temperature increases, these cultivars may be at risk of being lost.