Answer: When choosing tomatoes for canning, one of the major considerations is high acidity which contributes to a safe canned product, although it's easy to add citric acid or lemon juice to assure safe storage. A second consideration for canning is whether you want the majority of your harvest at in a short time (choose a determine variety), or prefer the production over the entire season (chose an indeterminate variety). Other than those considerations, it's up to you which you choose. Tomatoes which are usually listed as a good canning variety are often hi-acidic determinate varieties which will produce a large crop over a short period of time, rather than all season long.
Some varieties generally listed for canning include Mortgage Lifter, which is very meaty with few seeds. Bradley is a long time Southern favorite for canning, and Arkansas Traveler is a Southern heirloom well known for its ability to produce in hot weather. Santa Clara Canner originated in Italy. It's mid-sized tomatoes are juicy yet solid. It is an indeterminate variety.
There are varieties of seedless tomatoes. They are called parthenocarpic meaning they will set fruit at a cooler temperature and do not require pollination to set fruit. However, only the earliest maturing of these tomatoes will be seedless. Those produced later in the season will contain seeds (that's where the seeds come from for growing seedless tomatoes!) These varieties are seedless: Oregon Pride, Oregon Spring, Santiam and Siletz. They're all available from Territorial Seed Company, P. O. Box 157, Cottage Grove, OR 97424 Phone (541) 942-9547
http://www.territorial-seed.com and Tomato Growers Supply, http://www.tomatogrowers.com 1-888-478-3476
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