Fruits

We are actively engaged in pursuing research to determine the genetic factors that contribute to the development, ripening and quality of fleshy fruits. We primarily use tomato as a model system for studying fruit biology but we are also interested in using next generation sequencing and comparative genomics to investigate signaling pathways in additional Solanaceae species.  

• Modeling respiration of apple slices in modified-atmosphere packages
• Inhibition of fungal activity and enhancement of aroma biosynthesis in apple slices
• Changes in chlorophyll flurorescence of apple fruit during maturation, ripening and senescence
• Respiratory and fermentative metabolisms in asparagus tips under low O2/High CO2 atmosphere
• Regulation of the steady state oxogen in asparagus spears tips: responses of glycolytic metabolism and sucrose-metabolizing enzymes under low oxogen/high carbon dioxide atmospheres
• Phosphate and nucleotide metabolism under low O2 and high CO2 partial pressures in the tips of harvested asparagus spears stored at 1 degree Celsius
• Aroma biology and biochemistry

 Consumer and market research, business marketing and management.

Current research is focused on (1) chemical management of crop load on fruit quality and flower initiation to increase cropping efficiency and (2) factors affecting cuticular penetration of foliar-applied plant growth regulators to optimize the dose response relationship.

The main areas of our research are:

• Carbon assimilation by fruit crops

• Carbon partitioning in fruit crops, c)the effect of biotic and abiotic stress on assimilation and carbon partitioning

• Understanding the response of trees to biotic stress

• Establishing damage thresholds for stone fruit based on a carbon based model

Current Research in biotic stress: We have completed work on the effect of simulated leaf damage for strawberry, apple, and have initiated experiments with cherry.

• Sweet cherry research
• Tart cherry research
• Comprehensive pubs
• Fruit bud hardiness
• Stone fruit releases
• Apple NC140 project
• ASHS Podcasts
• Virtual Cherry Project 2007
• High Tunnel Cherry Project 2006/2007
• Great Lakes Expo High Tunnel Workship - Cherries 2008
• Northwest Orchard Show 2008/2009

View Great Lakes Fruit Workers

Tree Fruit Horticulture & Physiology

A primary focus is on cultural (orchard development) and physiological (reproductive and environmental stress) factors important to efficient production of high-value tree fruits. My laboratory has tended to take a diverse and integrative research approach through studies of meristem determination and growth regulation, carbon and nitrogen assimilation and partitioning, rootstock evaluation, and environmental limitations to refine orchard systems and management, primarily in stone fruits.

 Sweet Cherry Genetic Improvement

A primary focus is on identification, evaluation, and development of important traits found within sweet cherry scion and rootstock germplasm to enhance fruit quality and reduce production inputs, such as fungicides.

Nematode management in fruit production systems with particular emphasis on virus-vectoring nematodes and understanding rhizosphere ecology.

Rootstock evaluation of tree fruit (1980-2006)

A principal part of our research program is spent on evaluating new rootstocks for apple, cherry, peach and plum. The emphasis in apple is on finding new rootstocks that adapt to Michigan conditions and fit into high and moderate planting systems. These stocks are also being evaluated under various management systems. These trials serve a dual purpose in generation of data for research and as focal points in extension programming for workshops on rootstocks and training of high density apple systems. For tart cherry, we continue to recommend the standard Mahaleb rootstock and through our systematic trials have begun to change commercial sweet cherry growers over from the standard Mazzard seedling rootstock to the new clonally propagated MXM 2 and MXM 60 rootstocks. These rootstocks have proven to influence varieties to crop better and survive longer in less than optimum soil conditions. As a leader in the NC 140 Regional rootstock trial committee on pome and stone fruit rootstocks, we were able to organize new trials for evaluating dwarfing cherry rootstocks from Europe. Several of the German stocks in these trials have drawn considerable national and international attention.

Perennial root system studies related to soil dynamics

Over the years we have graduate students working on projects related to soil dynamics and physiology of fruit tree rootstocks and their root systems. Work was conducted on the relationship of soil stresses to the decline of cherry trees. Root system studies were conducted on the impact of root system health, morphology and longevity. We conducted field studies in growing tart cherry, apple and peach on raised beds at the Clarksville Hort Exp Station. We found after 10 years that cherry and peach survival was much higher on beds and that apple on MM 106 rootstock was not affected. The soil and site selected for the study was more well drained than expected and desired.

Dr. Bernard Zandstra does research on weed control in fruit, ornamental, and vegetable crops. Current projects include weed control in seedling Christmas trees, controlled flaming for weed control between rows of vegetables, reduced rates of herbicides in vegetable crops, and new herbicides for residual control in fruit crops. Dr. Zandstra authors the Michigan Weed Control Guide for Vegetable Crops bulletin and the weed control section of the Michigan Fruit Management Guide. He also is Field Research Director of the IR-4 Center (National Program for Minor Use Registrations) at Michigan State University.