About Us|Our Team
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Academic Qualifications
- Ph.D., University of Hawai'i, Mānoa
- B.S., University of Hawai'i, Mānoa
Current Research
Our projects involve tissue culture and transformation of tropical crops like papaya and anthurium and micropropagation of koa and a few other plants. Field evaluation of non-genetically modified (non-GM), Papaya ringspot virus (PRSV) resistant papaya (Carica papaya) developed by colleagues in Australia and the Philippines has been initiated with Richard Manshardt and Steve Ferreira, University of Hawaii. Anthurium projects with University of Hawaii colleagues Richard Criley, Tessie Amore, and Anne Alvarez are marker-assisted breeding and transformation for novel colors of large, heart-shaped anthuriums. A koa clonal propagation project headed by Nicklos Dudley, HARC forester, includes micropropagation of putative fungus wilt tolerant seedlings.
Transgenic (GM), PRSV resistant papaya developed about 20 years ago (Fitch et al., 1992; Fitch, 2010) by our team saved the Hawaii papaya industry but some consumers and growers do not wish to use GM products. Non-GM, PRSV resistant papaya resulted after 20 years of papaya backcrossing by Rod Drew and Simeona Siar using a hybrid between PRSV susceptible papaya and resistant wild relative, Vasconcellea quercifolia. We wish to determine if the new papaya hybrids are as resistant to Hawaii's PRSV as they are to Australian and Philippine strains. If resistant, hybrids between the new papayas and important Hawaii cultivars will be made. The non-GM Hawaii hybrids should provide alternatives to organic farmers and consumers.
Anthuriums had been transformed earlier for bacterial blight and nematode resistance in collaboration with the Pacific Basin Agricultural Research Center. We published our methods to improve transformation of anthurium (Fitch et al., 2011). About 800 independently transformed lines were developed by our team that included Heather McCafferty, Judy Zhu, Terryl Leong, and Xiaoling He of HARC. The plants are under field evaluation in Hilo.
While transgenic anthuriums for blight resistance were created, we also embarked on a marker-assisted breeding project for blight resistance. We are developing quick screening bioassays to classify a population of susceptible and resistant heart-shaped anthurium seedlings in order to discover DNA markers associated with blight resistance. Markers would enable breeders to eliminate blight susceptible hybrids from commercial releases, thereby saving growers from losses caused by blight infection.
Novel new colors like blues and purples in large, heart-shaped anthuriums could increase revenues for anthurium growers in Hawaii. Gene constructs for these colors are being developed. We are preparing anthurium cultures to be transformed.
Nick Dudley developed a koa selection system for Fusarium wilt tolerance by growing germinated seedlings in medium infected with the fungal pathogen. Surviving seedlings were rooted as cuttings and also micropropagated by our group. Although we have about 30 different clones in culture, only about 16 were scored for rooting as cuttings. Eight of the 16, considered to be good rooters, are desired for installing in replicated field tests on three different islands. Micropropagation is focused on these selections. We are attempting to micropropagate koa from mature trees in the field.
Our projects involve tissue culture and transformation of tropical crops like papaya and anthurium and micropropagation of koa and a few other plants. Field evaluation of non-genetically modified (non-GM), Papaya ringspot virus (PRSV) resistant papaya (Carica papaya) developed by colleagues in Australia and the Philippines has been initiated with Richard Manshardt and Steve Ferreira, University of Hawaii. Anthurium projects with University of Hawaii colleagues Richard Criley, Tessie Amore, and Anne Alvarez are marker-assisted breeding and transformation for novel colors of large, heart-shaped anthuriums. A koa clonal propagation project headed by Nicklos Dudley, HARC forester, includes micropropagation of putative fungus wilt tolerant seedlings.
Transgenic (GM), PRSV resistant papaya developed about 20 years ago (Fitch et al., 1992; Fitch, 2010) by our team saved the Hawaii papaya industry but some consumers and growers do not wish to use GM products. Non-GM, PRSV resistant papaya resulted after 20 years of papaya backcrossing by Rod Drew and Simeona Siar using a hybrid between PRSV susceptible papaya and resistant wild relative, Vasconcellea quercifolia. We wish to determine if the new papaya hybrids are as resistant to Hawaii's PRSV as they are to Australian and Philippine strains. If resistant, hybrids between the new papayas and important Hawaii cultivars will be made. The non-GM Hawaii hybrids should provide alternatives to organic farmers and consumers.
Anthuriums had been transformed earlier for bacterial blight and nematode resistance in collaboration with the Pacific Basin Agricultural Research Center. We published our methods to improve transformation of anthurium (Fitch et al., 2011). About 800 independently transformed lines were developed by our team that included Heather McCafferty, Judy Zhu, Terryl Leong, and Xiaoling He of HARC. The plants are under field evaluation in Hilo.
While transgenic anthuriums for blight resistance were created, we also embarked on a marker-assisted breeding project for blight resistance. We are developing quick screening bioassays to classify a population of susceptible and resistant heart-shaped anthurium seedlings in order to discover DNA markers associated with blight resistance. Markers would enable breeders to eliminate blight susceptible hybrids from commercial releases, thereby saving growers from losses caused by blight infection.
Novel new colors like blues and purples in large, heart-shaped anthuriums could increase revenues for anthurium growers in Hawaii. Gene constructs for these colors are being developed. We are preparing anthurium cultures to be transformed.
Nick Dudley developed a koa selection system for Fusarium wilt tolerance by growing germinated seedlings in medium infected with the fungal pathogen. Surviving seedlings were rooted as cuttings and also micropropagated by our group. Although we have about 30 different clones in culture, only about 16 were scored for rooting as cuttings. Eight of the 16, considered to be good rooters, are desired for installing in replicated field tests on three different islands. Micropropagation is focused on these selections. We are attempting to micropropagate koa from mature trees in the field.
Selected Publications:
Fitch MMM, TCW Leong, X He, HRK McCafferty, YJ Zhu, PH Moore, D Gonsalves, HS Aldwinckle, HJ Atkinson. 2011. Improved transformation of anthurium. HortScience 46:358-364.
Fitch MMM. 2010. Papaya ringspot virus (PRSV) resistance in papaya: update on progress worldwide. Transgenic Plant Journal 4:16-28.
Nishijima KA, MM Wall, MM Fitch, LS Sugiyama, RC Keith, WT Nishijima. 2010. Evaluating Hawaii-grown papaya for resistance to internal yellowing disease caused by Enterobacter cloacae. HortScience 45:1357-1364.
He X, SC Miyasaka, Y Zhou, MM Fitch, YJ Zhu. 2010. Regeneration and transformation of taro (Colocasia esculenta) with a rice chitinase gene enhances resistance to Sclerotium rolfsii. HortScience 45:1-7.
Wall MW, KA Nishijima, MM Fitch, WT Nishijima. 2010. Physicochemical, nutritional and microbial quality of fresh-cut and frozen papaya prepared from cultivars varying in resistance to internal yellowing disease. J Food Qual 33:131-149.
Fitch MMM, Moore PH, Leong TCW, Akashi LAY, Yeh AKF, White SA, Dela Cruz AS, Santo LT, Ferreira SA, Poland LJ. 2005. Clonally propagated and seed-derived papaya orchards: 1. Plant production and field growth. HortScience 40: 1283-1290.
Fitch MMM, Moore PH, Leong TCW, Akashi LAY, Yeh AKF, White SA, Dela Cruz AS, Santo LT, Ferreira SA, Poland LJ. 2005. Clonally propagated and seed-derived papaya orchards: 2. Yield comparison. HortScience 40: 1291-1297.
Fitch MMM, Manshardt RM, Gonsalves D, Slightom JL, Sanford JC. 1992. Virus resistant papaya plants derived from tissues bombarded with the coat protein gene of papaya ringspot virus. Bio/Technology 10:1466-1472.
Fitch MMM, Manshardt RM. 1990. Somatic embryogenesis and plant regeneration from immature zygotic embryos of papaya (Carica papaya L.). Plant Cell Rep 9:320-324
Fitch MMM, Manshardt RM, Gonsalves D, Slightom JL, Sanford JC. 1990. Stable transformation of papaya via microprojectile bombardment. Plant Cell Rep 9:189-194
Fitch MMM, TCW Leong, X He, HRK McCafferty, YJ Zhu, PH Moore, D Gonsalves, HS Aldwinckle, HJ Atkinson. 2011. Improved transformation of anthurium. HortScience 46:358-364.
Fitch MMM. 2010. Papaya ringspot virus (PRSV) resistance in papaya: update on progress worldwide. Transgenic Plant Journal 4:16-28.
Nishijima KA, MM Wall, MM Fitch, LS Sugiyama, RC Keith, WT Nishijima. 2010. Evaluating Hawaii-grown papaya for resistance to internal yellowing disease caused by Enterobacter cloacae. HortScience 45:1357-1364.
He X, SC Miyasaka, Y Zhou, MM Fitch, YJ Zhu. 2010. Regeneration and transformation of taro (Colocasia esculenta) with a rice chitinase gene enhances resistance to Sclerotium rolfsii. HortScience 45:1-7.
Wall MW, KA Nishijima, MM Fitch, WT Nishijima. 2010. Physicochemical, nutritional and microbial quality of fresh-cut and frozen papaya prepared from cultivars varying in resistance to internal yellowing disease. J Food Qual 33:131-149.
Fitch MMM, Moore PH, Leong TCW, Akashi LAY, Yeh AKF, White SA, Dela Cruz AS, Santo LT, Ferreira SA, Poland LJ. 2005. Clonally propagated and seed-derived papaya orchards: 1. Plant production and field growth. HortScience 40: 1283-1290.
Fitch MMM, Moore PH, Leong TCW, Akashi LAY, Yeh AKF, White SA, Dela Cruz AS, Santo LT, Ferreira SA, Poland LJ. 2005. Clonally propagated and seed-derived papaya orchards: 2. Yield comparison. HortScience 40: 1291-1297.
Fitch MMM, Manshardt RM, Gonsalves D, Slightom JL, Sanford JC. 1992. Virus resistant papaya plants derived from tissues bombarded with the coat protein gene of papaya ringspot virus. Bio/Technology 10:1466-1472.
Fitch MMM, Manshardt RM. 1990. Somatic embryogenesis and plant regeneration from immature zygotic embryos of papaya (Carica papaya L.). Plant Cell Rep 9:320-324
Fitch MMM, Manshardt RM, Gonsalves D, Slightom JL, Sanford JC. 1990. Stable transformation of papaya via microprojectile bombardment. Plant Cell Rep 9:189-194