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 Managing Color Disorders  

  Project Objectives

Color Disorders 

Presentations   Color Disorders vs. Soil    Preliminary Results  "Hartz" Ratio Calculator Related Links Participants



  Project objectives 

Fruit ripening disorders affect both the appearance and nutritional quality of tomatoes, reducing efficiency and return on investment for growers and the processing industry. Universities, growers and processors are working to develop an integrated management system to improve quality and nutritional value while reducing color disorders of tomato. 

Other important objectives of this long term project include testing equations based on soil nutrients as a predictor for ripening disorders; evaluating the economic feasibility of methods for preventing color disorders by agronomic means; and using gene expression profiling to determine whether there is a single disorder or multiple disorders with unique causes.

Research in University test plots and growers fields shows that soil test data can help us predict if a field may be at risk for producing tomatoes with yellow shoulder disorder.  The most important indicators of risk are the ratio of potassium to the square root of magnesium (the “Hartz” ratio), potassium levels, organic matter, and soils pH.  The buttons below will provide you more information on each.

 Click on the picture below to know more about color disorders of tomato.


Tomato Quality Starts with the Soil [Click here to get a PDF file] 

Presentation from the 2003 Ohio Fruit and Vegetable Growers Congress:  Managing processing tomatoes for quality  [Click here to get a PDF file]

* PDF files require Adobe Acrobat Reader. Download Acrobat Reader 5.0 for free.*

Click on the picture to know more about color disorders X soils.

Preliminary Results:

How to read the graphs pH Organic Matter Potassium "Hartz" Ratio

Click on the button above to estimate the "Hartz" ratio for your soil.

Related Links

University of California - Davis
Processing tomato production in California. 

Vegetable Research and Information Center

The Ohio State University

2003 Ohio Vegetable Production Guide Bulletin 672-03

The Ohio Soil Database

Ohio Agronomy Guide: Bulletin 472

Homepage of The Ohio State University Extension Vegetable Crops

California Tomato Commission
The latest news and information about California field-fresh tomatoes and the California fresh tomato industry.

Department of Horticulture and Landscape Architecture - Purdue
This site offers a complete list of tomato links.

Participants of USDA/CSREES Project

David Francis
Assistant Professor
The Ohio State University

Thomas Sporleder 
Agricultural, Environmental and Development Economics 
The Ohio State University

Stephen A. Garrison 
Extension Specialist, Vegetable Crops 
Rutgers Agricultural Research and Extension Center

Chris Gunter 
Horticulture Specialist 
Southwest Purdue Agricultural Program

Avtar K Handa
Professor of Molecular and Postharvest Biology 
Purdue University

Tim Hartz 
University of California, Davis

Majid Foolad 
Associate Professor of Plant Genetics 
The Pennsylvania State University

Funding for this project through: