Pre-breeding in Passiflora subrotunda Mast.: Morphological and Reproductive Characterization at Different Light Levels

Abstract

Passiflora are ornamental plants that are appreciated as part of outdoor decor, composing pergolas and gardens, as well as in interior ornamentation where species tolerant to environments with less light availability are used. The objective of this study was to evaluate the influence of different levels of light and pot types on morphological and reproductive characteristics in Passiflora subrotunda and to support genetic breeding programs of ornamental passifloras. The conditions of 75% and 100% light favored vegetative morphological characteristics through the time (105 days). Floral characteristics also presented higher values along increasing light levels. All qualitative characters related to flower and plant coloration did not vary among genotypes. The species possesses diurnal anthesis and flowers throughout the year. Plants cultivated in concrete pots showed greater growth and flower production. Pollen grains (PGs) are large, with an isopolar form, a small polar area, and a long aperture, and amylaceous. Percentage of viable PG was high: above 97% using Alexander solution and reaching up to 91% with fluorescein diacetate. Stigmas were partially receptive during the flower’s opening period. Percentage of self-compatibility was lower, based on the higher fertilization rate through cross-pollination. These information will be used in planning of ornamental Passiflora-breeding programs, assisting in the selection of characteristics and breeding methods.