About

Mark P. Bridgen is a professor in the School of Integrative Plant Science, Horticulture Section, and Plant Breeding and Genetics Section at Cornell University. His research program encompasses both basic and applied projects focused on new plant development and breeding, plant environment interactions, plant cell and tissue culture, in vitro plant breeding, genetic modifications for plant improvement, plant propagation, and the growth and development of ornamental and floricultural plants. He specializes in in vitro breeding techniques such as somaclonal and gametoclonal variation, embryo culture, somatic embryogenesis, mutation breeding, meristem culture for pathogen-free plants, and in vitro fertilization. His applied studies include herbaceous ornamental plants, field-grown cut flower production, use of high tunnels for season extension, greenhouse crop production, and cultivar evaluations. Since joining Cornell, he has developed and patented two ornamental Alstroemeria cultivars, 'Tangerine Tango' and 'Mauve Majesty'. Bridgen has received numerous awards and honors for his contributions to horticulture and plant sciences, including the American Society for Horticultural Science Distinguished Achievement Award for Ornamental Plant Breeding in 2023 and the Citizen of the Year Award from the Long Island Farm Bureau in 2024.

Research topics

• Horticulture
• Biology
• Botany
• Chemistry

Selected publications

• Breeding impatiens for resistance to impatiens downy mildew (<i>Plasmopara obducens</i>)

  Acta Horticulturae · 2025-07-01

  article1st authorCorresponding
  PublisherDOI

• Micropropagation of Hemp (Cannabis sativa L.)

  HortScience · 2023 · 28 citations

  Senior authorCorresponding
  • Biology
  • Horticulture
  • Botany

  Hemp ( Cannabis sativa L.) is commonly grown for the medicinal secondary metabolites produced by pistillate inflorescences. Micropropagation is a valuable method of propagating hemp plants because of the aseptic process and the production of true-to-type propagules. The hemp cultivar TJ’s CBD was used for a series of experiments to compare media inputs and practices for the clonal micropropagation of hemp. For stage I, shoot tips harvested from stock plants that were grown in a growth chamber produced less endogenous contamination in newly established cultures than shoot tips harvested from the greenhouse. In addition, stage I disinfection treatments with 20%, 40%, and 60% bleach (7.5% sodium hypochlorite) for 10 minutes had no differences in surface contamination rates. All concentrations were able to clean explants equally, and no damage to the explants was observed. For stage II, there were no differences in growth and multiplication rate between shoot tip or nodal explants. In addition, no differences were observed between the gelling agent’s agar, agargellan, and gellan gum at standard rates. When basal nutrient formulations were compared at standard rates and with their respective vitamins, Murashige and Skoog, Linsmaier &amp; Skoog, and Driver &amp; Kuniyuki Walnut media were found to be superior to Lloyd &amp; McCown Woody Plant Medium. Media pH levels of 4.0, 5.0, 5.8, 6.0, and 7.0 were compared, and no differences were observed in final fresh weights, shoot lengths, or quality ratings. The pH levels of 5.8, 6.0, and 7.0 generated a greater number of lateral nodes. Sucrose levels of 0%, 1.5%, 3.0%, 4.5%, and 6.0% (wt/vol) were also compared, with the 1.5% and 3.0% rates showing greater fresh weights, shoot lengths, and quality ratings. Growth room temperatures of 22, 24, 26, and 28 °C were compared, with temperatures of 28 and 26 °C generating greater fresh weights, shoot lengths, numbers of nodes, and quality ratings compared with cooler temperatures. The cytokinins 6-enzylaminopurine (BA), 6-(γ,γ-dimethylallylamino) purine (2iP), and thidiazuron (TDZ) were compared at 1.0, 5.0, and 10.0 μM concentrations. The 5.0-μM TDZ treatment generated greater fresh weights and numbers of lateral nodes; however, it also produced the shortest shoot lengths and lowest quality ratings. The 2iP treatments at 1.0 and 5.0 μM, and the BA treatment at 1.0 μM produced the greatest quality ratings. The 5.0-μM 2iP level was considered the best treatment for stage II multiplication based on high ratings, in addition to the greater final fresh weights, shoot lengths, and numbers of nodes that were produced. For stage III experiments, the auxins indole 3-butyric acid (IBA) and 1-naphthylacetic acid (NAA) were compared at concentrations of 0.25, 0.5, and 2.5 μM. Auxin treatments of 0.25 μM NAA, 0.5 μM NAA, and 2.5 μM IBA generated the greatest final shoot fresh weights, root fresh weights, and numbers of nodes. However, the 2.5-μM IBA treatment resulted in a higher overall rating. For stage IV, ex vitro rooting and acclimation trials compared a dome and an intermittent mist system, as well as treated the unrooted cuttings with an externally applied auxin. Acclimating with a dome produced greater shoot heights, fresh shoot weights, and overall ratings compared with the mist system. The auxin treatment mildly increased fresh root weight, but was not as important to acclimation success as the domed environment. It has been concluded that a micropropagation system that uses lower rates of sucrose, higher growing temperatures, and lower rates of the cytokinins BA and 2iP are optimal for the micropropagation of hemp. In addition, when acclimating hemp plants from tissue culture, an in vitro stage III can be bypassed and plants can be rooted ex vitro during stage IV acclimation with a dome with or without additional auxin treatments.

  PublisherOA PDFDOI

• Examining the stages of micropropagation for hemp (<i>Cannabis sativa</i>)

  Acta Horticulturae · 2023

  1st authorCorresponding
  • Botany
  • Horticulture
  • Biology
  PublisherDOI

• Molecular and morphological characterization of new interspecific hybrids of alstroemeria originated from A. caryophylleae scented lines

  Euphytica · 2019-04-11 · 22 citations

  articleOpen accessSenior author

  Abstract Alstroemeria is a genus native to South America from which many varieties of ornamental plants have been developed and introduced into the market. Interspecific hybridization followed by embryo rescue has been one of the most common breeding techniques to obtain new varieties. This study was aimed at obtaining alstroemeria hybrids through interspecific crosses using novel scented parental lines and assessing these hybrids. A total of 3669 embryos were rescued, from which 18 flowering plants were morphologically evaluated. Flower stem length ranged from 25 (14E07) to 83 cm (14A11) and most of the flowers showed pink/white colors with stripes over the inner tepals. Only 3 hybrids were perceived as scented and one of them (14E08) was evaluated through GC-MS analysis, detecting 9 VOCs, all of them monoterpenes. Molecular analysis using RAPD markers clustered two main groups: (A) hybrids with A. pelegrina as parental line and (B) hybrids coming from the crossing UC05 × C3 and its reciprocal. Moreover through this analysis was possible to subcluster hybrids coming from different seasons. A protocol for obtaining alstroemeria hybrids was successfully developed for this species using molecular and phenotypic evaluation to provide information about their pedigree and to spot those traits which are attractive for the ornamental plant market.

  PublisherOA PDFDOI

• Tissue Culture Clonal Propagation of Hybrid White Oaks for the Urban Environment

  HortScience · 2019-12-01 · 8 citations

  articleOpen accessSenior author

  A tissue culture system was developed to clonally propagate a series of hybrid white oaks ( Quercus L.) at the plant breeding program of the Urban Horticulture Institute (UHI), Cornell University. From 2014 through 2018, 34 genotypes and 1966 individual explants of UHI hybrid white oaks were trialed to determine their capacity to establish, multiply, and root in a tissue culture environment. UHI hybrid oak genotypes were selected based on their known tolerance to stresses common in the urban environment (drought, alkaline soils, pests, and diseases) and their ornamental qualities. Individual genotype was the single largest factor affecting successful establishment, multiplication, stabilization, and rooting of hybrid oaks in vitro. Thirteen clones of hybrid oaks were identified as having the capacity to stabilize and grow continuously in the multiplication phase. Multiplication efficiency rates were dependent on individual genotype. Stabilized genotypes showed the capacity to be re-established during successive years. The tissue culture process was simplified and refined to make the protocols less labor intensive for laboratory technicians using these methods. This study presents a preliminary and promising method for the clonal propagation of oak species and provides a path for cultivar development for plants belonging to the genus Quercus .

  PublisherOA PDFDOI

• Plant Tissue Culture Techniques for Breeding

  Handbook of plant breeding · 2018-01-01 · 43 citations

  book-chapter1st authorCorresponding
  PublisherDOI

• Direct and indirect shoot organogenesis from leaves of Torenia fournieri

  2018-04-27

  article1st authorCorresponding
  PublisherDOI

• Alstroemeria

  Handbook of plant breeding · 2018-01-01 · 15 citations

  book-chapter1st authorCorresponding
  PublisherDOI

• The 2017 National Floriculture Forum: Engaging Young People in the Industry

  HortTechnology · 2017-12-01

  articleOpen accessSenior author
  PublisherOA PDFDOI

• Micropropagation of <i>Vitex agnus-castus</i>^©

  Acta Horticulturae · 2017-10-01

  articleSenior author
  PublisherDOI

Frequent coauthors

• Elizabeth Kollman

  11 shared

• Richard E. Veilleux

  Virginia Tech

  9 shared

• LU Chun-sheng

  China Electronics Standardization Institute

  9 shared

• Nina Bassuk

  Cornell University

  9 shared

• Miles Schwartz Sax

  U.S. National Arboretum

  9 shared

• Chad T. Miller

  Colorado State University Pueblo

  8 shared

• George C. Elliott

  University of Connecticut

  7 shared

• Christopher S. Cramer

  New Mexico State University

  6 shared

Awards & honors

• Citizen of the Year Award from the Long Island Farm Bureau (…
• American Society for Horticultural Science (ASHS) Distinguis…
• Alex Laurie Award for Research and Education from the Societ…
• Association of Public and Land-grant Universities (APLU) Inn…
• Elected national president of Pi Alpha Xi (2018)