Fruits

• 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

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 the tree rootstock research program is spent on evaluating new rootstocks for our primary crops in Michigan; apple, cherry, peach and plum. The goal for these crops is to find rootstocks that can help make tree production a profitable and sustainable enterprise. In apple, we have focused on finding new rootstocks that adapt to Michigan conditions and fit into high density modern planting systems. These stocks are also being evaluated under various management systems. These trials serve a dual purpose in generation of data for research with findings disseminated to growers directly or through extension educators. Field testing of rootstocks is still a long term process of some 10-20 years which today is carried out by Dr. Greg Lang at MSU. The apple industry is almost exclusively planting many of the dwarfing clonal rootstocks in new Vertical Axe and Tall Spindle plantings. For tart cherry, the standard seedling rootstock, Mahaleb, is still the standard which has been used for over 300 years. We continue to try new rootstocks which can reduce tree canopy size, resist soil maladies such as anaerobic soils, Phytophthora and Armillaria. Sweet cherry has been following apple industry lead by focusing on rootstocks which reduce canopy size to facility fresh harvest and like tart cherry for the processing industry, rootstocks that resist soil maladies. The peach industry still relies primarily on peach seedling rootstocks but seeks clonal rootstocks which resist anaerobic soil conditions. As a leader in the NC 140 Regional rootstock trial committee on pome and stone fruit rootstocks, rootstock researchers at MSU have coordinated and organized trials in a number of states and regions.

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. Zandstra authors the weed control section of the Michigan Fruit Management Guide. Current projects study new herbicides for residual control in fruit crops, including: strawberry, apple, blueberry, cherry, peach, and raspberry.