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Breaking Physiological Dormancy in Tubers of Solanum chacoense Christian T. Christensen 1, Lincoln Zotarelli 1, Kathleen Haynes 23 Kathleen Haynes 2,and.

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Presentation on theme: "Breaking Physiological Dormancy in Tubers of Solanum chacoense Christian T. Christensen 1, Lincoln Zotarelli 1, Kathleen Haynes 23 Kathleen Haynes 2,and."— Presentation transcript:

1 Breaking Physiological Dormancy in Tubers of Solanum chacoense Christian T. Christensen 1, Lincoln Zotarelli 1, Kathleen Haynes 23 Kathleen Haynes 2,and Mihai Giurcanu 3 1 Department of Horticultural Sciences, University of Florida, Gainesville, FL, 32611, 2 USDA-ARS, Beltsville, MD 20705, 2 USDA-ARS, Beltsville, MD 20705, 3 Department of Statistics, University of Florida, Gainesville, FL, 32611

2 Outline Introduction Current Challenges ObjectiveMaterialsMethod Preliminary Results Conclusions

3 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)

4 Gibberellins Exogenous gibberellins can be used to break dormancy in potato tubers –Brian et al. (1955) and Hemberg (1985) GA 3 is typically used in seed certification programs –Suttle (2004)

5 Current Challenges Solanum chacoense (chc) has shown difficulty breaking dormancy which may result in uneven emergence

6 Objective To determine an appropriate concentration of gibberellic acid (GA 3 ) and soak time to encourage breaking dormancy in chc

7 Materials and Methods 11 genotypes of chc across four accessions Separated by size evenly across 12 treatments –Small (1.4g avg.) –Medium (2.5g avg.) –Large (5.8 avg.) AccessionGenotypePI #Country Chc AA-3, A-5, A-6PI Argentina Chc BB-3, B-5, B-10PI Argentina Chc CC-6, C-8PI Bolivia Chc DD-6, D-7, D-8PI Paraguay Left to Right: Small, Medium, And Large

8 Materials and Methods Treatments Protocol GA 3 – Fischer Scientific International Inc. GA 3 dissolved in DI water for two hours Tubers were treated with desired treatment Tubers air dried for 30 minutes GA 3 (μg/ml)Soak Time (min.)

9 Materials and Methods CRD with 3 replicates Maintained in an incubator at 25 ºC Sprout number every 2 days Study duration of 46 DAT

10 Statistical Analysis 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

11 Results EffectNum DFPr > F GA Minutes Size2<.0001 Genotype10<.0001 GA 3 *Minutes GA 3 *Genotype30<.0001 Minutes*Genotype GA 3 *Minutes*Genotype GA 3 *Size Minutes*Size GA 3 *Minutes*Size Genotype*Size GA 3 *Genotype*Size Minutes*Genotype*Size GA 3 *Minutes*Genotype*Size Main effects –GA 3 –Genotype –Size Interactions –GA 3 xGenotype

12 Main effects: GA 3 Proportion of Sprouting EffectNum DFPr > F GA Minutes Genotype10<.0001 Size2<.0001 B A A A GA 3 concentrations greater than 0 µg/ml were more successful at breaking dormancy overall GA 3 concentrations greater than 0 µg/ml were more successful at breaking dormancy overall Time had no affect on % tuber sprouting

13 Main Effects: Genotype Proportion of Sprouting Genotypes showed large variation in % tuber sprouting EffectNum DFPr > F GA Minutes Genotype10<.0001 Size2<.0001 A B B B C CDCD D D E E E

14 Main Effects: Size Proportion of Sprouting A B C Direct Correlation between tuber size and % tuber sprouting Direct Correlation between tuber size and % tuber sprouting EffectNum DFPr > F GA Minutes Genotype10<.0001 Size2<.0001

15 Interactions: GA 3 x Genotype NS

16 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

17 Conclusion GA 3 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

18 Questions

19 Literature Cited Bethke, P Potato Tuber Dormancy. USDA ARS Vegetable Crops Research Unit and UW Department of Horticulture Brian, P.W., H.G. Hemming, and M. Radley A physiological comparison of gibberellic acid with some auxins. Physiol Plant 8: Errebhi, M., C.J. Rosen, S.C. Gupta, and D.E. Birong. 1998b. Potato yield response and nitrate leaching as infl uenced by nitrogen management. Agron. J. 90:10–15. Errebhi M, C.J. Rosen, F.I. Lauer, M.W. Martin, and J.B. Bamberg Evaluation of tuberbearing Solanum species for nitrogen use efficiency and biomass partitioning. Amer JPotato Res 76: Hemberg, T Potato rest. In: PH Li(ed), Potato Physiology, Academic Press, New York. Pp Opena, G.B. and G.A. Porter Soil management and supplemental irrigation effects on potato: II. Root growth. Agronomy Journal 91, 426–431. Suttle, J.C Physiological Regulation of Potato Tuber Dormancy. Amer J of Potato Res 81:

20 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


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