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Establishing an Accelerated Breeding Pipeline for Apple (Malus domestica) Through the Implementation of Short-Juvenility-Period by BpMADS4.

Hemphill, Daniel Stewart
http://rave.ohiolink.edu/etdc/view?acc_num=osu1735330092597879

Abstract Details

2025, Master of Science, Ohio State University, Horticulture and Crop Science.
Apples are the most consumed fruit in the U.S. and so play a crucial role in the nation's economy. However, traditional apple breeding is hampered by a prolonged juvenility period, during which seedlings do not produce flowers or fruit for up to 10 years. This delay poses significant challenges in the development of new cultivars that can meet the growing demands of an increasing population, evolving market preferences, and changing climate conditions. This study outlines the development and implementation of an accelerated breeding pipeline designed to address these issues by enhancing traits related to aesthetics, yield, and phytochemicals beneficial to human health by implementing the short juvenile period (SJP) trait, so improvement of these traits, consolidations of new trait combinations, and the rate of genetic gain is enhanced more rapidly through manipulating the apple breeding cycle. The foundation for this accelerated approach was lain by Henryk Flachowski in 2007 by using Agrobacterium-mediated transfer of the BpMADS4 gene from silver birch to the apple genotype named PinS (Pinova  Idared). These SJP genotypes are capable of significantly reducing breeding cycle duration via their implementation into crossing schemes, making them ideal candidates for inclusion in an advanced breeding program. This project has successfully integrated these SJP trees into a systematic breeding strategy conducted under greenhouse conditions. Over the course of three years, we utilized environmental controls, detailed genotypic data, and selected genetically diverse parents to cultivate more than 10,000 seedlings. This effort resulted in achieving two apple harvests within 14 months, thereby validating the effectiveness of the accelerated breeding pipeline. A key component of our strategy involved the use of a 50k SNP array and analysis of variation of gametophytic self-incompatibility diplotypes (S-alleles) to maintain and enhance genetic diversity while optimizing crossbreeding approaches. Furthermore, factor analysis of mixed data (FAMD) presented a rapid but thorough method for identifying genetic distances, which facilitated the selection of optimal parent combinations that promote desirable traits while preserving genetic variability. The implications of these findings are significant for the future of apple breeding. By overcoming the natural constraints associated with the juvenility period, our accelerated breeding pipeline not only speeds up the development of new apple cultivars but allows the incorporation of traits that have been previously neglected in conventional breeding programs. This novel approach offers a framework capable of rapidly adapting to market demands, logistic needs, and could transform apple breeding practices by augmenting speed, efficiency, and targeted trait improvement. This thesis presents a comprehensive account of establishing an accelerated apple breeding program from its inception to its implementation, highlighting its potential to revolutionize breeding practices. The success of this program demonstrates its feasibility and effectiveness, suggesting that such strategies could be applicable in broader horticultural practices, particularly in the context of enhancing global food security and nutrition.
Jonathan Fresnedo-Ramirez (Advisor)
Jessica Cooperstone (Committee Member)
Diane Miller (Advisor)
Chieri Kubota (Committee Member)
224 p.
Agriculture; Botany; Food Science; Horticulture
Horticulture, Accelerated, Breeding, Apple, Malus, Transgene, Transgenic

Recommended Citations

Citations

  • Hemphill, D. S. (2025). Establishing an Accelerated Breeding Pipeline for Apple (Malus domestica) Through the Implementation of Short-Juvenility-Period by BpMADS4. [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1735330092597879

    APA Style (7th edition)

  • Hemphill, Daniel. Establishing an Accelerated Breeding Pipeline for Apple (Malus domestica) Through the Implementation of Short-Juvenility-Period by BpMADS4. 2025. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1735330092597879.

    MLA Style (8th edition)

  • Hemphill, Daniel. "Establishing an Accelerated Breeding Pipeline for Apple (Malus domestica) Through the Implementation of Short-Juvenility-Period by BpMADS4." Master's thesis, Ohio State University, 2025. http://rave.ohiolink.edu/etdc/view?acc_num=osu1735330092597879

    Chicago Manual of Style (17th edition)

osu1735330092597879
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This open access ETD is published by The Ohio State University and OhioLINK.
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