Creating New Apple Varieties by Cross-Breeding with Pear Genes

Jenn Hoskins
5th March, 2024

Creating New Apple Varieties by Cross-Breeding with Pear Genes

Image Source: Natural Science News, 2024

Key Findings

  • Scientists in Kyoto created new apple-pear hybrid seedlings
  • The hybrids show balanced genetic contributions from both apple and pear parents
  • This breakthrough could lead to fruit trees with better disease resistance and new flavors
In the realm of plant breeding, scientists continually strive to enhance the characteristics of crops by merging the genetic traits of different species or even different genera. This process, known as hybridization, can lead to new plant varieties that possess a combination of desirable features such as disease resistance, improved nutritional value, or novel flavors and textures. A recent study conducted by researchers at Kyoto Prefectural University has made significant strides in this field by successfully creating hybrid seedlings from two important fruit tree genera: apple (Malus) and pear (Pyrus)[1]. The significance of this achievement lies in the potential to overcome the challenges of hybrid lethality, a phenomenon where the offspring of two different species may not survive past the embryonic or seedling stages[2]. This barrier has historically limited the ability to combine genetic material from distantly related plants, thereby constraining the diversity and advancement of agricultural crops. The Kyoto Prefectural University study's success in producing living, growing hybrids signals a breakthrough in bypassing this limitation. The study's methodology involved cross-pollinating Malus × domestica (common apple) with different species of Pyrus, including Pyrus communis (European pear), P. bretschneideri (Chinese white pear), and an interspecific hybrid of P. communis and P. pyrifolia (Asian pear). The resulting seeds were then nurtured in controlled laboratory conditions to promote germination and growth. The researchers were able to acclimatize the seedlings, ensuring they could survive independently, marking a pivotal step in the development of intergeneric hybrid plants. To confirm the hybrid nature of the seedlings, the team employed a suite of analytical techniques. Leaf morphology was examined for traits indicative of both parental species. Flow cytometry, a technique that measures the amount of DNA in cells, was used to verify that the hybrids had the expected genetic composition. Lastly, molecular genotyping, which identifies specific genetic markers, was used to ensure that the genomic fragments from both Malus and Pyrus were present in the hybrids. The results of the genotyping were particularly noteworthy; the hybrids inherited genomic fragments symmetrically from both parents. This finding is crucial, as it suggests a balanced contribution of genetic material, which is often a challenge in intergeneric crosses. Previous studies have shown that apple and pear genomes are highly co-linear, meaning they share a similar structure, which may have facilitated this balance[3]. Furthermore, the use of an interspecific Pyrus hybrid as one of the parents provided a unique genetic bridge, incorporating the genetic background of P. pyrifolia into Malus × domestica. The research at Kyoto Prefectural University has not only demonstrated the possibility of creating new intergeneric hybrids but also provided a foundation for future breeding efforts. The availability of whole-genome sequences for Pyrus has expanded the potential for understanding and manipulating pear genetics and genomics[4]. Additionally, the genome sequence of the Japanese pear 'Nijisseiki' has been used to support breeding programs, offering insights into the physiology and evolutionary history of these fruit trees[5]. By successfully developing these hybrid seedlings, the researchers have laid the groundwork for future studies that can further explore the transfer of valuable traits between Malus and Pyrus. This could lead to the production of novel fruit varieties with enhanced disease resistance, such as resistance to fire blight, a common and devastating bacterial disease in these fruit trees[3]. In summary, the study from Kyoto Prefectural University represents a remarkable advancement in the field of plant breeding. By overcoming the reproductive barriers that have traditionally restricted the genetic exchange between apple and pear trees, this work opens the door to a new era of fruit crop improvement. The implications of these findings are vast, promising a future where fruit trees are not only more robust and resistant to disease but also offer enhanced flavors and nutritional benefits to consumers worldwide.

BiotechGeneticsPlant Science

References

Main Study

1) Introduction of a diverse genetic background of Pyrus into Malus through intergeneric hybridization.

Published 2nd March, 2024

https://doi.org/10.1007/s00438-024-02131-8

Related Studies

2) Understanding and overcoming hybrid lethality in seed and seedling stages as barriers to hybridization and gene flow.

https://doi.org/10.3389/fpls.2023.1219417

3) Molecular characterization of intergeneric hybrids between Malus and Pyrus.

https://doi.org/10.1093/hr/uhac239

4) Pear genetics: Recent advances, new prospects, and a roadmap for the future.

https://doi.org/10.1093/hr/uhab040

5) Chromosome-scale genome assembly of Japanese pear (Pyrus pyrifolia) variety 'Nijisseiki'.

https://doi.org/10.1093/dnares/dsab001


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