Progress 10/01/03 to 09/30/08
Outputs
OUTPUTS: Multi-state collaborative research on the environmental effects of postharvest disorders of 'Honeycrisp' apple fruit was performed. The disorders included soft scald and bitter pit. The environmental effects included orchard location, tree location, fruit location, production temperature, and storage temperature, duration, and atmospheric conditions. Genetic variability related to fruit textural changes of the 'Honeycrisp' cultivar and its progeny was also studied. Crispness of 'Honeycrisp' and its progeny was measured using a TA.XT2 texture analyzer at harvest and after storage. Levels of RNA and enzyme activities of proteins involved in cell wall degradation were measured in these genotypes, and correlated to textural changes. A website describing 'Honeycrisp' research with links to peer-reviewed publications and searchable by location of work or by disorder was designed and uploaded. It is currently hosted on a University of Minnesota server. Other research findings were disseminated to growers at commodity group meetings, shared with colleagues at regional meetings, and made available to the scientific community through peer-reviewed publications. PARTICIPANTS: The principal investigator and Minnesota representative to this multi-state project is Cindy Tong. A graduate student, Harpartap Mann, completed his M.S. and Ph.D. performing research under this project. Collaborators on this project within the University of Minnesota included David Bedford and James Luby, apple breeders, and Zata Vickers, texture expert in Food Science and Nutrition. Outside collaborators included Randolph Beaudry, Michigan State University; James Mattheis, USDA-ARS; Christopher Watkins, Cornell University; and Sarah Weis, University of Massachusetts. Other than Harpartap Mann, three undergraduate students and one visiting graduate student from Korea were trained in conducting research under this project. TARGET AUDIENCES: Target audiences for this work include other scientific researchers interested in apple fruit storage, especially that of new cultivars, or in fruit textural changes. This group would gain new knowledge through the website or through peer-reviewed publications. The other target audience for this work is apple growers, who learned about new knowledge gained from this project through presentations at commodity group meetings, commodity group newsletter articles, personal phone calls, e-mail exchanges, and the website. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Knowledge outcomes included an increased understanding of the physiology of bitter pit and soft scald development in 'Honeycrisp' apples. Ideas for future research due to gaps in knowledge were also uncovered. Action outcomes include discussion of possible future grant proposal collaborations and other multi-state research collaborations. The 'Honeycrisp' research website has been used by growers to gain information useful for dealing with buyers and in furthering their understanding of how to produce high quality 'Honeycrisp' fruit. The project has been evaluated as part of the revision of the entire multi-state collaboration.
Publications
- Tong et al. 2008. Honeycrisp Apple Research Results. http://smfarm.cfans.umn.edu/Honeycrisp.htm. University of Minnesota.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Results from 2007 were shared at the annual NE-1018 Postharvest Physiology of Fruit multistate project meeting in Lake Tahoe, California in July, 2007. A written report was presented, and a short summary for the multistate report was prepared.
PARTICIPANTS: Harpartap Mann, a graduate student, worked in this project. Collaborators included James Luby and David Bedford, apple breeders.
TARGET AUDIENCES: The target audience for this work are researchers interested in apple fruit postharvest softening or quality maintenance in various apple genotypes.
Impacts
Findings from this project contributed to objective 4 of the multistate project - to expand knowledge of the influence of cultivar, production practices, and postharvest handling on the nutritinal and eating quality of fruit. Enzyme activities of polygalacturonase, beta-galactosidase, and arabinofuranosidase were measured in fruit of different apple genotypes at 2 week intervals from harvest to 8 weeks in storage at 0 C. There was no correlating pattern of enzyme activities, indicating that changes in enzyme activities of these cell wall degrading enzymes alone cannot explain why some apple fruit stay crisp during storage. Work required to break cylinders of apple fruit from various apple genotypes, including Honeycrisp progeny, were measured at harvest and after 4 months of storage at 0 C. One of the Honeycrisp progeny studied was MN1914, which has recently been released by the Minnesota Experiment Station. Significant changes in work values between harvest and storage
are indicative of softening. Our data suggest that the ability to maintain crispness during storage may be heritable.
Publications
- No publications reported this period
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Progress 01/01/06 to 12/31/06
Outputs
Changes in fruit crispness of various progeny of Honeycrisp and other apple varieties were completed. The work required to fracture 'Honeycrisp' fruit mesocarp did not change between harvest and 4 months of storage, varying between 1800 and 2000 g/mm. In contrast, the work required to fracture fruit mesocarp of a sibling of 'Honeycrisp', 'MN1708', decreased from 2000 g/mm at harvest to 400 g/mm after 4 months of storage. This shows that the ability of 'Honeycrisp' to maintain its crispness is truly unusual. Work required to fracture fruit from 'MN1915', a progeny of 'Honeycrisp', did not change significantly between harvest (2200 g/mm) and 4 months of storage (1800 g/mm). This shows that the ability of 'Honeycrisp' to maintain fruit crispness can be passed on to its progeny. Molecular genetic and biochemical analyses of these progeny are ongoing.
Impacts
Data from our experiments show that maintainess of fruit crispness can be inherited. Our results will help breeders select for crispy apple fruit earlier in the breeding process, which now takes 15-20 years. This will allow for earlier release of economically successful varieties like Honeycrisp.
Publications
- Lester, GE and CBS Tong. 2006. Introduction to the colloquium: Making fruits and vegetables flavorful, nutritive, and convenient to eat. HortScience 41: 58.
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Progress 01/01/05 to 12/31/05
Outputs
In order to help breeders develop new, crisp apple varieties, we wanted to find reliable and quantifiable insrumental methods for measuring fruit crispness. We integrated data from a snapping test, confocal laser scanning microscopy (CLSM), and sensory panels to predict sensory crispness. Change in Work, as measured with a TA.XT2 texture analyzer, was able to predict change in Crispness, as determined by a sensory panel. These data suggest that although postharvest physiologists may be able to use Change in Work with storage in lieu of sensory evaluations to measure changes in apple fruit crispness, breeders will have to continue to rely on sensory panels to evaluate fresh fruit crispness. We then measured sensory Crispness, Work, and average cell number of several different apple genotypes at harvest and after 4 months of cold storage. `Honeycrisp' and one of its progeny, `MN1915', maintained their crispness, did not exhibit a measurable change in work required to
fracture fruit cortical tissue, and had lower average cell numbers than the other apple genotypes. `MN1802', a genotype unrelated to `Honeycrisp', had similar attributes. These data suggest that in order to develop crisp apples, breeders may want to look for apple fruit with a relatively small average number of cells, and that crispness maintenance, like that found in `Honeycrisp', is probably heritable.
Impacts
Our data suggests that apple breeders must take into account factors other than cell wall number and size, and fracturability of cell walls when screening for crispness of apple fruit at harvest. However, objective measurements of the work required to fracture fruit tissue can be used as a measure for crispness maintenance with storage.
Publications
- Mann, H, D Bedford, J Luby, Z Vickers, and C Tong. 2005. Relationship of instrumental and texture measurements of fresh and stored apples to cell number and size. HortScience 40:1815-1820.
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Progress 01/01/04 to 12/31/04
Outputs
In 2004, several trees of Honeycrisp progeny had enough fruit to start storage studies. Fruit were harvested from trees resulting from crossing Honeycrisp with MN447, MN1702, MN1760, MN1849, Salute, or Fortune. Crispness of the fruit, as measured by the work required to break cylinders of cortex tissue from these fruit, was measured. Variability in crispness was detected within the Honeycrisp progeny, Honeycrisp, and the other parental genotypes. Fruit are now being stored and their crispness will be assessed after 3 months of storage at 0C.
Impacts
We will determine whether the crispness of Honeycrisp fruit, and the ability of Honeycrisp fruit to maintain this crispness during storage is heritable. This information will help breeders develop new, crisp apple fruit that stay crisp for months after harvest.
Publications
- No publications reported this period
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