Back to top

Plant Physiology

Current Research:

Irrigation water management.  Water management is arguably one of the most critical issues affecting the cranberry industry for four major reasons, (a) crop production, (b) environmental concerns, (c) costs and (d) regulatory scrutiny.  The objectives of this research project is to (i) develop a Crop Water Stress Index (CSWI) using soil moisture monitoring devices such as tensiometers, moisture sensors along side with water level floats, (ii) develop a relationship between soil tension and volumetric water content, and (iii) evaluate impact of water management on cranberry photosynthesis and fruit yield factors. Traditionally, cranberry beds receive 1 inch of water per week from either rain, capillary action from the groundwater, irrigation or some combination of these. This experiment has been conducted on commercial cranberry beds on (i) sand based beds and (ii) peat based beds (mixed layers of sand, peat and organic matter).

Frost Cycling in Cranberry Production: Effects of Frost Protection Method. Frost protection using the principle of thermal heat of fusion is one of the best management practices in cranberry production. Frost cycling on a frost night is a new management technique being used to protect against cold temperature, reduce water usage resulting in both water and energy savings. However, the response of each cultivar and especially the newly introduced cultivars such as Crimson Queen, DeMoranville, and Mullica Queen and others to this new approach is relatively unknown. Temperature dynamics that occur during frost cycling have not been studied. Temperature probes and sensors used to initiate frost protection have been subject to colossal errors and in some instances resulting in frost damage of an entire cranberry bed. In this project we intend to do field studies monitoring different frost protection methods and their effect on a number of commonly grown cultivars including new introductions. In the freezing chamber, we will study temperature probe calibration with the hope to identify limitation ranges in temperature accuracy. We hope research data obtained will help growers in choosing an effective frost protection approach and also choosing appropriate temperature sensors/probes for their sets of conditions.

Shade Effects on chlorophyll content and nutrient content of cranberry vines exhibiting yellow vine syndrome. Our research objective is to evaluate the effect of shading on the chlorophyll content and nutrient content of cranberry vines exhibiting yellow vine symptoms. The chlorophyll content and photosynthetic activities were investigated by spectrometric, high pressure liquid chromatography (PHLC) and in vivo Chl fluorescence kinetics.

Leaf Gas Exchange in Cranberry Cultivars. Managing plant water stress is critical to cranberry production. Plant gas exchange and photosynthesis and stomatal activity data can provide a highly sensitive measure of the degree of water stress to which a plant is exposed. Currently there are no studies comparing the photosynthetic capacity of recently introduced cultivars of cranberry with that of established cultivars. Photosynthesis measurements and gaseous exchange readings will be collected from Crimson Queen, Demoranville, Howes, Stevens and Early Black. Measurements include photosynthesis rate, transpiration, stomatal conductance of water vapor and sub-stomatal cavity CO2 concentration.

Subsurface Water Drainage and Irrigation System. Wet conditions as a result of inadequate drainage in cranberry production could potentially result in increased root rot and fruit rot diseases, inhibition of root development, reduced fruit retention and reduced productivity.  Subsurface tile drainage provides a mechanism for removing excess moisture from the soils by draining to field capacity in a reasonable time so that plant growth is not significantly impaired. Without artificial drainage, plants have difficulty establishing a healthy root system on poorly drained soils since excess water prevents air and oxygen from getting to the plant root zone. This project is evaluating the potential to (i) remove excess water from the cranberry beds and (ii) irrigate from below ground. Tile drainage(s) were installed in both new and established beds, although on old beds installation was far more challenging.  Four tile spacing(s) and two depths of installation in the soil are being evaluated on commercial cranberry beds.

Selected Research Publications

Jeranyama, P. and J Sack. 2015. Temperature and photosynthetically active radiation effect on carbon assimilation in cranberry cultivars. HortScience 50(9):S13. (Abstr.)

Ndlovu, F., P. Jeranyama, and C. DeMoranville. 2015. Evaluation of cold hardiness changes during acclimation in cranberry cultivars grown in Southeastern Massachusetts. HortScience 50(9):S7. (Abstr.)

Peter Jeranyama, Faith Ndlovu, Carolyn DeMoranville and Casey Kennedy. 2015. Temperature set-point effect on cranberry bud damage in frost cycling. NACREW 2015. Presentation archived at

Faith Ndlovu, Peter Jeranyama and Carolyn DeMoranville. 2015. Evaluation of cold hardiness changes during acclimation in cranberry cultivars grown in Massachusetts. NACREW 2015. Presentation archived at:

Jeranyama, P., C. DeMoranville, and J. Waddell. 2014. Using Canopy Temperature, Soil Tension and Moisture Measurements as Tools in Cranberry Irrigation. Proc. 10th Int. Symp. on Vaccinium and other Superfruits. Acta Horticulturae (ISHS) 1017:487-492.

Ghantous, K.M., H.A. Sandler, W.R. Autio, and P. Jeranyama. 2013. Response of cranberry vines to hand-held flame cultivators. HortScience 48:870-874.

Ghantous, K.M., H.A. Sandler, W.R. Autio, and P. Jeranyama. 2012. Hand-held flame cultivators as a management option for woody weeds. Weed Technology 26:371-375.

Fan Zhang, Zi Wei, Peter Jeranyama, Carolyn DeMoranville and Harvey Hou. 2011. A significant loss in photosynthetic activity associated with the yellow vine syndrome of cranberry. HortScience 46(6):901-907.

Wi, Zi, Peter Jeranyama, Fan Zhan, Carolyn DeMoranville, and Harvey Hou. 2010. Probing the mechanism of the yellow vine syndrome development in the American Cranberry: Shade effects. HortScience 45(9):1345-1348.

Jeranyama, Peter and Carolyn J. DeMoranville. 2009. Gas Exchange and chlorophyll content of cranberry under salt stress. Acta Horticulturae 810:753-758.

Betserai Nyoka, Peter Jeranyama, Vance Owens, Arvid Boe and Michael Moechnig. In Biofuels: Alternative Energy. Management Guide for Biomass Feedstock Production from Switchgrass in the Northern Great Plains. Pearson Education Company, OK. 2008. pp12.