Dynamic Pollen–Stigma Coordination in <i>Dendrobium</i> Hybridization: A Strategy to Maximize Fruit Set and Hybrid Seed Viability
This study investigated dynamic pollen–stigma coordination to optimize interspecific hybridization in <i>Dendrobium</i> using <i>D.</i> ‘Burana Jade’ as the maternal parent and eight wild species as pollen donors. Stigma receptivity was comprehensively evaluated using a multi...
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| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-05-01
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| Series: | Horticulturae |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2311-7524/11/5/544 |
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| Summary: | This study investigated dynamic pollen–stigma coordination to optimize interspecific hybridization in <i>Dendrobium</i> using <i>D.</i> ‘Burana Jade’ as the maternal parent and eight wild species as pollen donors. Stigma receptivity was comprehensively evaluated using a multi-indicator approach, including morphological characterization (crystal secretion and bulging papillae), histochemical benzidine-H<sub>2</sub>O<sub>2</sub> staining, and enzymatic activity profiling (esterase and superoxide dismutase). Concurrently, pollen viability was assessed through TTC testing coupled with ultrastructural observations. Results identified a critical synchronization window: pollen viability peaked at 1–3 days post anthesis (DPA) or during the mid-anthesis phase, while stigmas exhibited maximal receptivity when secretory activity and antioxidant enzyme levels significantly increased. Using stage-specific pollination criteria, 8.4% of crosses (8/95) produced viable fruits, outperforming empirical methods by 2.8-fold. <i>D.</i> ‘Burana Jade’ showed cross-compatibility with four <i>Dendrobium</i> species (<i>D. aphyllum</i>, <i>D. chrysotoxum</i>, <i>D. hercoglossum</i>, <i>D. thyrsiflorum</i>), with <i>D. thyrsiflorum</i> hybrids achieving 54.81% embryogenesis and 22.38% germination. Three compatible combinations germinated successfully in vitro within 45–55 days on 1/4 MS medium supplemented with 20 g/L sucrose, 1 g/L tryptone, 180 mL/L coconut water, and 2.2 g/L Phytagel. Our findings establish that synchronizing pollen viability windows with stigma receptivity phases significantly enhances fruit set and hybrid seed viability, providing a phenology-driven strategy to overcome reproductive barriers in orchid breeding programs. This study provides key physiological criteria for <i>Dendrobium</i> hybridization, though their applicability to other orchids needs validation. Future multi-omics studies should explore cross-species compatibility mechanisms. |
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| ISSN: | 2311-7524 |