Monday, February 3, 2014

Selecting Tomato Varieties by Rebecca Anderson

Winter is a great time to research tomato varieties
The seed catalogs are filling my mailbox, making me anxious for spring. I've been trying to narrow down my favorite tomato varieties, but it's tough. All the pictures are beautiful and the descriptions are amazing. How is one to choose?  Modern hybrid or heirloom?  Determinate or indeterminate?  To help with the decision process I've been looking at a study by Tom Fowler, Horticulture Specialist with the University of Missouri Extension Service.  He conducted a field trial in 2013 measuring the production 47 different varieties of tomatoes.  Although one year's worth of data from one state does not provide much opportunity to study tomato varieties in multiple environmental conditions, when considering varieties by classification, Mr. Fowler did come to some useful conclusions.

For this study, an heirloom tomato was considered a variety that was open-pollinated and would grow from true from seed.  They were varieties that could be documented for at least 50 years and/or had been passed down by several generations of family. Modern hybrids were created by specific plant breeding and did not grow true from seed.  Generally heirlooms produced larger fruit than modern varieties but modern varieties produced more pounds of fruit per plant. 

Determinate varieties are more compact plants with fruit that ripen over a shorter period of time. Indeterminate tomato vines are larger and rangy and require more support.  Indeterminate plants will have a longer harvest period than determinate tomatoes.  The study found that among both heirloom and modern hybrid varieties, indeterminate vines produced larger fruit while determinate vines had larger total yields. 
Now I need to focus my tomato production goals. Do I want to grow a record setting gigantic tomato?  Then I should look for an indeterminate heirloom variety. Do I want to have a lot of tomatoes ripen at the same time so I can do all my canning and preserving at once?  Maybe I need a determinate modern hybrid tomato.  I'll probably plant a couple of varieties so I can accomplish a little of both.  Hopefully I find something that will produce regardless of the environmental surprises Colorado has in store for 2014.

More information about this study, including data on individual varieties can be found in the Kansas State University Research and Extension Horticulture Newsletter, January 14, 2014 and January 21, 2014 editions.