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Breaking Physiological Dormancy in Tubers of Solanum chacoense. Christian T. Christensen 1 , Lincoln Zotarelli 1 , Kathleen Haynes 2 ,and Mihai Giurcanu 3 1 Department of Horticultural Sciences, University of Florida, Gainesville, FL, 32611, 2 USDA-ARS, Beltsville, MD 20705,
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Breaking Physiological Dormancy in Tubers of Solanumchacoense Christian T. Christensen1, Lincoln Zotarelli1, Kathleen Haynes2,and Mihai Giurcanu3 1Department of Horticultural Sciences, University of Florida, Gainesville, FL, 32611, 2USDA-ARS, Beltsville, MD 20705, 3Department of Statistics, University of Florida, Gainesville, FL, 32611
Outline • Introduction • Current Challenges • Objective • Materials • Method • Preliminary Results • Conclusions
Dormancy Factors • Genetic Makeup • Stage of Tuber Development • Environmental Conditions during tuber growth and storage • Bethke (2013) • Hormone contributions: • Abscisic acid (ABA) and Ethylene: induction • Cytokinin: loss of dormancy • Suttle (2004)
Gibberellins • Exogenous gibberellins can be used to break dormancy in potato tubers • Brian et al. (1955) and Hemberg (1985) • GA3 is typically used in seed certification programs • Suttle (2004)
Current Challenges • Solanumchacoense(chc)has shown difficulty breaking dormancy which may result in uneven emergence
Objective • To determine an appropriate concentration of gibberellic acid (GA3)and soak time to encourage breaking dormancy in chc
Materials and Methods • 11 genotypes of chcacross four accessions • Separated by size evenly across 12 treatments • Small (1.4g avg.) • Medium (2.5g avg.) • Large (5.8 avg.) Left to Right: Small, Medium, And Large
Materials and Methods Treatments Protocol GA3 – Fischer Scientific International Inc. GA3 dissolved in DI water for two hours Tubers were treated with desired treatment Tubers air dried for 30 minutes
Materials and Methods • CRD with 3 replicates • Maintained in an incubator at 25 ºC • Sprout number every 2 days • Study duration of 46 DAT
StatisticalAnalysis • Binary logistic regression model- proportion of sprouting • SAS statistical package for Windows (SAS Systems for Windows Version 9.2, SAS Institute Inc. Cary, NC, USA) • PROC GLIMMIX
Results Main effects GA3 Genotype Size Interactions GA3xGenotype
Main effects: GA3 Proportion of Sprouting • GA3 concentrations greater than 0 µg/ml were more successful at breaking dormancy overall • Time had no affect on % tuber sprouting A A A B
Main Effects: Genotype Proportion of Sprouting • Genotypes showed large variation in % tuber sprouting A B B B C C D D D E E E
Main Effects:Size Proportion of Sprouting • Direct Correlation between tuber size and % tuber sprouting A B C
Interactions:GA3x Genotype A AB A A BC A A C A A A A A A B A A B A B B B NS A A A B NS B B NS NS
Conclusion • Direct Correlation between tuber size and % sprouted tubers • Genotypes showed variation in % sprouted tubers with D-6, D-7, and D-8 exhibiting the strongest dormancy • Genotypes from Argentina exhibited weaker dormancy mechanisms while those originating from Bolivia or Paraguay exhibited a stronger dormancy mechanism
Conclusion • GA3 concentrations greater than 0 µg/ml were more successful at breaking dormancy overall • Soak time had no affect on breaking dormancy • No single treatment combination broke dormancy across all genotypes
Literature Cited • Bethke, P. 2013. Potato Tuber Dormancy. USDA ARS Vegetable Crops Research Unit and UW Department of Horticulture • Brian, P.W., H.G. Hemming, and M. Radley. 1955. A physiological comparison of gibberellic acid with some auxins. Physiol Plant 8:899-912 • Errebhi, M., C.J. Rosen, S.C. Gupta, and D.E. Birong. 1998b. Potato yield response and nitrate leaching as influenced by nitrogen management. Agron. J. 90:10–15. • Errebhi M, C.J. Rosen, F.I. Lauer, M.W. Martin, and J.B. Bamberg. 1999. Evaluation of tuberbearingSolanumspecies for nitrogen use efficiency and biomass partitioning. AmerJPotato Res 76:143-151. • Hemberg, T. 1985. Potato rest. In: PH Li(ed), Potato Physiology, Academic Press, New York. Pp 353-388 • Opena, G.B. and G.A. Porter. 1999. Soil management and supplemental irrigation effects on potato: II. Root growth. Agronomy Journal 91, 426–431. • Suttle, J.C. 2004. Physiological Regulation of Potato Tuber Dormancy. Amer J of Potato Res 81:253-262
Acknowledgments • USDA-ARS Beltsville, MD • Kathleen Haynes: Committee Member • Karen Frazier: T.C. Technician • University of Florida • Lincoln Zotarelli: Advisor • Mihai Giurcanu: Statistician • Rebecca Darnell: Committee Member • Charles ‘Ethan’ Kelly: Lab and Field Technician