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Tomato Terminology

Okiedawn OK Zone 7
16 years ago

In a different thread, a new tomato grower asked for the definition of indeterminate and determinate tomatoes.

Writing about the differences in the two types of tomatoes got me thinking about all the tomato terminology we use. I thought I'd post some of it here to help out the new tomato growers among us.

Tomato--Lycopersicon esculentum but more accurately Lycopersicon lycopersicon.

Currant tomatoes--Lycopersicon pimpinellifolium.

The other seven species of the genus Lycopersicon are inedible.

OPEN POLLINATED tomatoes reproduce true from seed.

HYBRID TOMATOES are created by crossing 2 or more varieties. In general they DO NOT come true from seed, but some have been dehybrized into an open-pollinated form.

HEIRLOOM TOMATOES are generally those which have been passed down via seed-saving from one generation to another, often within an extended family or a small community. Within the group of heirlooms, there are several sub-categories:

--FAMILY HEIRLOOMS are varieties that someone originally selected for and stabilized genetically and then passed down the seed through multiple generations. Many were brought to the US by immigrants who carried their favorite seeds with them when they came to this country. Many family heirlooms are now available commercially.

--COMMERCIAL HEIRLOOMS are varieties introduced to the public by seed companies prior to 1940.

--CREATED HEIRLOOMS are varieties created deliberately by crossing either two known heirlooms or one known heirloom with one or more known hybrids. You have to grow these out for several successive generations to stabilize them.

--MYSTERY HEIRLOOMS are tomatoes resulting from a natural or unintentional cross-pollination between two or more varieties.


RED tomatoes are as their name

YELLOW tomatoes range from almost white or ivory to deep gold.

ORANGE tomatoes range from a golden orange to a deep pure bright orange.

PINK tomatoes are really light red. They are not bubble gum pink or Barbie doll pink.

PURPLE tomatoes are a deep dark blackish-red. They are NOT violet or the color of puple eggplant.

BLACK tomatoes are a deep reddish, maroonish, brownish, greenish color. They are not a deep dark black.

WHITE tomatoes are a pale, pale yellow or ivory. They are not white like snow.

GREEN tomatoes are green when ripe, and are often referred to as GWR tomatoes. They often have amber to yellow shoulders.

BI-COLOR tomatoes can be red and green or red, orange and yellow or red and orange, etc.

SYSTEMIC DISEASES are those that infect and/or affect the entire plant and are the most serious diseases plants face.

Common systemic diseases in our part of the country include the various strains of fusarian wilt, nematode infestation in the soil, and tobacco mosaic virus. Up north in the colder zones verticillium wilt is more of a problem. Some tomato plants have been bred to have resistance to or tolerance of some of these diseases and it is indicated by the use of the letters V,F, N, T, etc.

FOLIAGE DISEASES are common on tomato plants and there are many of them, including early blight, bacterial speck, septoria leaf spot, late blight and gray leaf speck. Of these, only late blight is quickly fatal. The others will defoliate a plant but can be survived.

ABIOTIC DISEASES are the problems that result from either a genetic condition or specific growing/environmental conditions. There are many of these, including:

--BLOSSOM END ROT, commonly referred to as BER. Often appears as a dry brown patch at the blossom end (bottom) of a fruit. IT is caused by several different stresses. There is also an internal blossom end rot but it is more rare. BER is often the result of a lack of calcium update due to cultural conditions and is common in the early part of the season.

--CATFACING often appears when pollination occurs during cool weather and includes abnormal scarring and shapes.

--CONCENTRIC CRACKING is the forming of concentric rings of split tissue around the fruit's stem end. It is a genetic condition.

--SUNSCALD results when the fruit sunburns due to inadequate foliar coverage. The fruit develops thin skin that is white, sort of blistered looking and is kind of shiny.

--GREEN SHOULDERS are also a genetic condition. The upper part of the tomato remains green or red streaked with green although the rest of the fruit is ripe.

--LONGITUDINAL CRACKING is splitting that runs from the top to the bottom of the fruit. It is caused by excessive rainfall or excessive irrigation.

--CURLING LEAVES are a common problem. Often it occurs because of a particular gene the tomato carries called the 'wilty gene'. Tomato leaves can curl for many reasons, including when the weather is either too cool or too hot, too wet or too dry, or has experienced a sudden change, like from cool and cloudy to sunny and hot.

REGULAR LEAF or REGULAR LEAVED (RL) is the term used for standard tomato foliage. RL foliage is a dominant trait.

POTATO LEAF or POTATO LEAVED (PL) is the term used for tomato foliage that resembles the foliage of potato plants.

PL foliage is a recessive trait.

RUGOSE LEAVES are puckered leaves. Both potato leaved varieties and rugose leaved varieties appear to exhibit better resistance to foliar diseases than that exhibited by regular leaved varieties.

PERFECT BLOSSOMS are those flowers which contain the male and female reproductive structures within the flower. They self-pollinate. Tomatoes have perfect blossoms.

DAYS TO MATURITY, often expressed as DTM, is the approximate time between transplantation of plants into the garden and the arrival of the first ripe fruit.

EARLY tomatoes are those that tend to produce fruit about 55 to 65 days from transplantation into the garden. They tend to be determinate varieties and usually are not as tasty as regular-season tomatoes. Early tomatoes seem to have more trouble with Blossom End Rot.

MID-SEASON tomatoes are those that tend to produce fruit about 65 to 80 days from transplantation into the garden. They tend to perform very well in our climate.

LATE-SEASON tomatoes are those that produce over 80 days after transplantation into the garden. They are not always the best producers in our climate.

PRUNING involves removing 'suckers' that appear as bew growth between stems. Suckers usually occur wherever two stems normally come together to form a V-shape. The decision about whether to prune or not can become quite contentious. I NEVER prune because doing so leads to less foliage which means less photosynthesis, less fruit and more sunscald.

There are many good seed companies that sell quality tomato seed which tends to have good germination rates and also to be the seed it is sold as. Unfortunately there are some companies whose seed is substandard, has low germination rates and sometimes ends up producing a tomato other than the one you thought you purchased. Some companies whose seed performance is reliable include Tomato Growers Supply Company, Sandhill Preservation Center, Totally Tomatoes, Victory Seed, Territorial Seed, Johnny's Selected Seed, Baker Creek Heirloom Seed and Heirloom Tomatoes.

"Cats" when used by tomato growers generally refers to caterpillars in general and specifically to tomato or tobacco hornworms. Other caterpillars you may encounter include tomato fruitworms (same thing as corn earworms) and cutworms.

Bt is the insecticide Bacillus thuringiensis that some people apply to their plants to control cats. Be advised that it will kill all the butterflies and moths who come into contact with it.

Mites are generally Red Spider Mites and they are a problem on tomatoes in hot weather.

I hope this list of some of the tomato terms we use is helpful to new growers. If I left out some of the common tomato terms, and I am sure that I did, I hope someone else will add them to this thread.


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