Nascimento et al. 2025 (Article) Wittmackia, Brazil, Atlantic Forest

Reproductive systems and hybridization for ornamental use of Wittmackia (Bromeliaceae) endemic to Brazil and occurring in the Atlantic Forest fragments

Author(s):—G.Q.S.d.S. Nascimento, F.V.D. Souza, L.Y.S. Aona, M.A.P.C. Costa & E.H. Souza

Publication:—Euphytica 221(4): 40. (2025) — DOI

Abstract:—Bromeliaceae family have great ornamental potential and a wide diversity of reproductive systems, floral characteristics and pollination strategies. Self-compatibility is commonly reported in Bromeliaceae, alongside occurrences of self-incompatibility and mixed reproductive systems. Hybridization enables the creation of genotypes with new combinations of shapes and colors, leading to the development of new ornamental cultivars for landscaping and horticulture. In this study we identify the reproductive systems, potential interspecific hybridizations and reproductive barriers of 16 species of the Wittmackia. To identify the reproductive systems, we evaluated natural pollination, spontaneous self-pollination, artificial self-pollination, cross-pollination, and agamospermy. The reproductive strategy was determined using the autogamy index, self-incompatibility index, and reproductive efficiency. Over 65% of the species studied showed self-incompatibility. No agamospermy was observed. We carried out 713 interspecific hybridizations in 84 different combinations with 16 species, resulting in 285 fruits from 44% of the pollinations. The main events of self-incompatibility and incongruence identified after crossings include low pollen germination on the stigma surface, inhibition of pollen tube growth in the stigma, interruption of pollen tube growth along the style with callose deposition, and coiling of pollen tubes inside the ovary, among others. The seeds generated from the different reproductive systems and hybridizations had germination rates above 85%, indicating the absence of post-zygotic barriers and high seed viability. The results of this study contribute to the understanding of reproductive systems and new hybridizations in Bromeliaceae, potentially leading to the creation of hybrid ornamental cultivars.

Keywords:—Bromelioideae · Fluorescence microscopy · Reproductive barriers · Selfincompatibility