Understanding Genetic Variety and Compatibility in Hydrangeas Using DNA Markers

Jim Crocker
6th August, 2024

Understanding Genetic Variety and Compatibility in Hydrangeas Using DNA Markers

Hydrangea macrophylla (pictured), one of the focal species of the study, showed high genetic affinity with H. serrata and superior maternal cross-compatibility, supporting its central role in strategies to expand genetic diversity and improve cold tolerance in commercial hydrangeas.

Photo adapted from: Claude Kolwelter / CC BY (Source)

Key Findings

  • The study, conducted in Korea, assessed genetic diversity in seven main hydrangea species using SSR markers
  • Researchers identified five distinct genetic groups among 35 hydrangea varieties, highlighting significant genetic diversity
  • Intraspecific hybrids were easy to produce, while interspecific hybrids required ovule culture due to genetic incompatibilities
Hydrangeas, popular for their large and colorful inflorescences, are widely used in floral arrangements and as cut flowers. However, the genetic diversity of commercially grown hydrangeas is limited due to a breeding focus on a few popular species. A recent study conducted by Chonnam National University aimed to address this limitation by suggesting interspecific breeding strategies to expand the genetic diversity in Hydrangea L. The study evaluated genetic diversity in seven main species collected in Korea and analyzed cross compatibility via intra- and interspecific hybridization[1]. The study used simple sequence repeat (SSR) markers to assess genetic diversity, resulting in the segregation of 35 varieties from seven species into five distinct groups: (1) Hydrangea paniculata group, (2) Hydrangea arborescens group, (3) Hydrangea anomala and Hydrangea aspera group, (4) Hydrangea quercifolia group, and (5) Hydrangea macrophylla and Hydrangea serrata group. This classification highlights the genetic diversity within the Hydrangea genus and provides a framework for future breeding efforts. Cross compatibility was tested through intra- and interspecific hybridization. Intraspecific hybrids, which involve crossing within the same species, were relatively easy to obtain. However, interspecific hybrids, which involve crossing between different species, were more challenging to produce due to various factors, including genetic incompatibilities. Most interspecific hybrids were obtained using ovule culture, a technique that involves culturing ovules in a controlled environment to promote hybrid development. Notably, hybrids between H. macrophylla and H. serrata were successfully created from seed sowing, indicating that H. serrata is a subspecies of H. macrophylla. The study also observed bilateral and unilateral incompatibilities across the obtained hybrids. Bilateral incompatibility occurs when both species in a cross are incompatible, while unilateral incompatibility occurs when only one species is incompatible. For example, weak bilateral compatibility was observed between H. serrata and H. paniculata. This finding suggests that hybrids between H. macrophylla and H. serrata can be used as parental materials in crossing with H. paniculata to improve cold tolerance in hydrangeas. The study's findings align with previous research on intrinsic postzygotic barriers, which are factors that reduce gene flow between species after fertilization has occurred. These barriers can play a significant role in speciation by reducing gene exchange between sympatric species pairs, promoting the evolution of reproductive isolation, and influencing speciation early in the process[2]. In the context of hydrangeas, the observed incompatibilities and successful hybridizations contribute to our understanding of how intrinsic postzygotic barriers can be managed to enhance genetic diversity in commercial breeding programs. Furthermore, the study found that cross compatibility was improved in interspecific crossings using H. macrophylla and H. arborescens as maternal plants. This suggests that selecting appropriate maternal plants can enhance the success rate of interspecific hybridization, thereby increasing the genetic diversity of commercially grown hydrangeas. In conclusion, the study conducted by Chonnam National University provides valuable insights into the genetic diversity and cross compatibility of hydrangeas. By identifying genetic groups and exploring hybridization techniques, the research offers practical strategies to expand the genetic diversity of commercially grown hydrangeas. These findings have the potential to improve the resilience and adaptability of hydrangeas, making them more suitable for various environmental conditions and enhancing their commercial appeal.

GeneticsBiochemPlant Science

References

Main Study

1) Evaluation of genetic diversity using simple sequence repeat markers and analysis of cross compatibility in hydrangeas

Published 5th August, 2024

https://doi.org/10.1007/s13580-024-00629-z

Related Studies

2) The importance of intrinsic postzygotic barriers throughout the speciation process.

https://doi.org/10.1098/rstb.2019.0533


Related Articles

An unhandled error has occurred. Reload 🗙