ASHS 2025 Conference

This study evaluated physiological and fruit quality traits of 24 intraspecific hybrid maypop (Passiflora incarnata) (Florida × Oklahoma) selections, grown in 3-gallon pots at the Mississippi Agricultural and Forestry Experiment Station South Mississippi Branch in Poplarville, Mississippi, in 2023. Summer physiological measurements revealed significant differences in stomatal conductance, ranging from 0.02 to 0.89 mol/m²s (0.29 mol/m²s average), transpiration, ranging from 0.31 to 7.98 mmol/m²s (3.65 mmol/m²s average), vapor pressure deficit, ranging from 0.83 to 2.56 kPa (1.51 kPa average), chlorophyll fluorescence, ranging from 0.38 to 0.67 (0.53 average), and fruit temperature, ranging from 32.00 to 39.33 °C (34.96 °C average) among selections. Significant differences were also observed in fruit size parameters, including height (45.53-64.94 mm; 56.94 mm average), width (33.83-56.32 mm; 49.56 mm average), shape (1.03-1.36 mm/mm; 1.16 mm/mm average), weight (15.41-59.66 g; 36.62 g average), and density (0.89-1.67 g/cm²; 1.25 g/cm² average). Pulp content also significantly differed, with total soluble solids ranging from 13.57 to 18.73 °Brix (15.90 °Brix average), titratable acidity from 14.77 to 23.33 g/L (17.96 g/L average), pH from 3.38 to 3.81 (3.59 average), total phenolic content from 363.72 to 603.88 mg GAE/L (481.33 mg GAE/L average), lightness (L*) from 73.94 to 80.91 (77.76 average), red-green value (a*) from -5.36 to 0.43 (-2.38 average), and yellow-blue value (b*) from 25.94 to 54.20 (39.62 average). Additionally, differential thermal analysis of the roots of these selections as well as their parents, revealed potential cold hardiness differences within P. incarnata, with Oklahoma roots exhibiting greater hardiness (-14.42 °C average) than Florida roots (-8.26 °C average), and hybrids showing intermediate tolerance (-10.53 °C average). Overall, these findings highlight the variability within P. incarnata, offering valuable insights for broader breeding efforts focused on enhancing both fruit quality and physiological traits within Passiflora.