Chuck Marr

Horticulture

Kansas State University

Chuck Marr

Horticulture

Kansas State University

What’s New in Tomatoes

What’s New in Tomatoes

Don’t start too early in the season.

In Manhattan, 20% chance of a freeze April 30

10% chance of a freeze May 5

5% chance of a freeze May 9

Soil temperature should be a consistent 55o F

Below critical soil temperature, plant roots don’t develop and plants don’t absorb nutrients properly.

Plants may survive but don’t ‘thrive’

‘Modern’ tomato varieties

Semi-determinate (‘determinate’) vine Uniform ripening genetic trait Multiple disease resistance Meaty, firm fruit

Heat tolerant genetic trait (Hot Set) Long Shelf Life (LSL) genetic trait

What is important?

Produce lots of tomatoes Foliage cover but easy to spray Fairly large size and uniform Produce early but sustained Few culls (cracks, Blossom-End Rot, etc) Disease resistance Taste good

Semi-Determinate or “Determinate”-”Compact” Vine Habit

Standard vine Determinate/Compact vine

Advantages of Compact VineAdapted to raised bed culture

Short cages or ‘stake-weave’

More stable in wind

Use less water and fertilizer

Closer spacing-more plants per row

Yields comparable to large vined types

Variations in vine size:

Uniform Ripening (UG Gene)

Fruit ripens uniformly- top to bottom and inside-outside. Uniformly ripe. No ‘green shoulder’ or waste when using.

Meaty Firm Fruit

Fruit holds into slices

Can be chopped or diced

Does not soften easily when stacked

Modern consumers prefer

Not irregular or rough like a ‘beefsteak’ type

Fusarium wilt in tomato. No known control. Persists for 8-12 years.

There are 2 strains or races F1 and F2. Need both resistance

(A new strain F3 has been discovered in the deep south)

Multiple Disease Resistance

Leaf blight (Early Blight and Septoria Leaf Spot) is a different story. There is some resistance available but hasn’t proven to be very effective in the field. Both are foliar fungus diseases-spores develop on leaves and don’t enter the roots of the plant.

Tomato Spotted Wilt (TSW) Virus

Stunted plants, purplish color. Mottled, marbled fruit

Spread by western flower thrips-primarily in greenhouse or transplants.

Bacterial Spot or Speck

Spots or specks on fruit, stem, and leaf. Usually a problem in cooler, wet conditions.

Copper fungicides- not as effective as blight control

Additional Disease Resistance

Fusarium 1 and 2 Fusarium 3 (a few varieties) Verticillium wilt (don’t have in KS) Tobacco mosaic virus (TMV) Nematodes (a problem south of I-70) Tomato spotted wilt virus (some coming) Bacterial speck and spot (a problem north

of I-70)

V,F1,2,3 N, TMV, TSWV, ASC, Bacterial Speck/Spot)

‘Modern’ Tomato Varieties

Merced- sturdy vine, good quality Mt. Spring-second early, good quality Celebrity- oldest of the semi-determinates Carnival- slightly larger than Celebrity

Some that we’ve relied on for several years. Still useful to consider for their reliability and consistency over the years.

Semi-determinate, F1,2 resistance, reliable production

Blossom drop from excessive summer heat.

Daytime 95 F, Night 75 F

Excessive N; Hot, dry winds make problem worse

A genetic trait- usually referred to as the Hot Set or Heat Set gene allows tomatoes to set under heat conditions.

Many new varieties now are being developed with the Hot Set gene incorporated.

Sun Leaper and Sunmaster have done well. Several newer varieties coming along with this characteristic.

Long Shelf Life (LSL) Tomato

When a tomato reaches a full size, green stage, it starts to produce an internal gas – ethylene- which ‘drives’ the ripening process. Continuous ethylene production continues after the tomato is fully ripe- then it becomes soft, squishy, and begins to rot.

LSL tomatoes can be held for a longer time after fully ripe with little loss of quality or flavor.

Have held tomatoes for up to 1 month after fully ripe and still edible. May not be useful to all growers but can improve shelf life of tomatoes if not sold quickly.

Pik Ripe 193 and Keepsake. Several newer varieties coming along with this trait as well.

Yes, but how do they TASTE!!

21 varieties

55 ‘tasters’

Whole tomatoes, cut slices and taste samples

Appearance

Color

Meatiness

Acidity

Sweetness

Texture

Rated on a 1-10 scale. Varieties were named and names visible to tasters.

Tomato ‘Taste’ Study

Appearance 6.8-8.7 5-10

Color 6.8-8.7 5-10

Texture 6.7-8.3 4-10

Acidity 3.4-5.4 3-10

Sweetness 4.2-5.0 2-9

Texture 4.7-7.6 3-9

Factor Variety Range Taster’ Range

Good fruit size .52 lb

Mid season harvest

Good quality

F3 Fusarium resistance

Fruit size .50 lb

Good quality

Compact vine, F1,2 resistance, small ‘stylar scar’, sturdy vine

What’s ‘really new’- so new that we have only limited testing (1 year in several locations).

Very limited seed or not released yet.

Will be evaluating more in the next few years….. But have several advantages to consider when they may become more widely available

Heat set

Good size .57 lb

Mid season Now named “Red Pride”

High early yield

Fair size .54 lb

Low culls

Large .59 lb

TSWV and F3 resistance

Early-midseason

Good yield

LSL type

Good size .52 lb

Good yield

Seed increase this year

Early-midseason

Good size .53 lb

Highest yield in our trial

Early-midseason

Very large fruit .67 lb

Low culls

Bact S and TSWV resistance

Early-midseason

Very large size .68 lb

A little rough

More culls

Bacterial wilt, F 1,2, and TSWV resistance

Moderate early yields

Good size .56 lb

Bacterial S resistance

Some pointed fruit

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