By Minette Tonoli
WELCOME TO THE FIRST IN A SERIES OF ALL THINGS TOMATO
When pollination takes place naturally, without human intervention, by the wind or insects, open pollination has taken place. Open pollinated varieties have a set of fixed characteristics and these characteristics are passed onto the offspring, producing plants that are true to type, essentially identical to the mother plant.
Open-pollinated varieties include heirloom varieties and (fixed) hybrid varieties.
“True to type” means that if you grow a plant from the seed of a tomato, it will be guaranteed to produce the same shape/colour/size/taste tomato as the parent plant.
An heirloom tomato is an open pollinated tomato cultivar whose seeds come true to type and have been passed down from generation to generation for at least the last 50 to 100 years.
Tomato connoisseurs love heirlooms, mostly because of their taste. They aren’t (always) the best looking – there are some beauties out there, but generally they don’t produce greatly uniform fruit (supermarket standard), and come in all sorts of strange colours, shapes, and sizes. And they don’t last long after picking either. But they really have great taste. Much, much better than most standard store-bought tomatoes.
Examples of heirloom tomatoes are Black Krim, Purple Russian, Green Giant, Hawaiian Pineapple
Hybrid is defined as the offspring of two plants of different varieties (or less often different species).
Hybrids are normally commercially bred, with human interference, by specifically crossing two plants with distinctly different traits to result in a better tomato.
Natural hybrids do exist too - a common example is Peppermint which is a hybrid cross between water mint and spearmint.
It must be kind of fun, playing around with hybrids! Some hybrids are created to let us have plants with better disease resistance, or that grow in specific conditions, such as cold areas, or for their particular growing habit traits, such as dwarf cultivars, and even to get plants with an increase in productivity, cross-country shipping etc.
Fixed hybrids breed true to type, and are the result of a long selection preceded by an original natural or induced hybridization.
So, as far as I understand it:
A + B = C
C + C = 50% A / 40% B / 8% C / 2 %D.
But growing out those C selections each year means that each subsequent “grow-out” resulted in more and more pure C’s until only C’s are produced.
I think this is also where the word grex comes in - originally borrowed from orchid breeding to define the collective word for all the offspring of two genetic individuals.
Example of a fixed hybrid tomato = Indigo Rose
Fixed hybrid can become heirlooms over many generations.
When two plants are crossed to always produce a consistent hybrid offspring in the first generation, that cross produces an F1 hybrid.
The F in F1 stands for filial, or daughter and the 1 refers to the first generation. So two different parent plants will produce offspring with specific sets of characteristics.
E.g. X + Y = Z
Where plant breeders found that if they cross pollinate plant X, which fruits abundantly but is susceptible to disease, with plant Y which is a poor producer but a healthy disease resistant plant, they get seeds that will grow into plant Z which is a moderately productive tomato plant that is more disease resistant.
Commercial F1 hybrid seeds generally do not stabilize or come true to type (as opposed to fixed hybrids like above) - this means you’ll always have to cross the two original parents to create the seeds that will result in the particular hybrid that you want to grow. So, Z + Z ≠ ZIf you did save seed from an F1 hybrid and grew the resulting plants, you may find that the plants are more closely related to either of the original parents, or something entirely different. Growing from an F1 produces F2 plants and growing from F2 plants results in F3 plants etc. E.g. X + Y = Z (an F1), Z + Z = Q (an F2), and Q + Q = R (an F3)
Example of F1 hybrid tomato: Rapunzel
WHAT’S IN THE SHOPS
Well, that depends, because some savvy shops now provide the discerning customer with a choice of heirlooms too, but the stock-standard red globe tomato you find in most supermarkets is most probably an F1 hybrid that was chosen for how many tomatoes a plant can produce, in a short time, early in the season, and how uniform they are in size, shape and colour, and very importantly, how well they keep (shelf life). Taste is pretty much last on the list of importance for mass produced tomatoes (own opinion) It’s there… no one will eat a totally disgusting tomato after all. But bland is bland.
The sheer difference in tastes that are available in heirlooms and fixed hybrids are just astounding – from complex flavours that are deep and dusky in some of the purple tomatoes to uplifting citrus-like flavour in many of the yellow ones.
DID YOU KNOW – Tomatoes come from South America?
DID YOU KNOW – Most original tomatoes were not red?
The complete Idiot’s Guide to Seed Saving and Starting, Alpha Books, 2012, Sheri Ann Richardson
Growing Gardens for Free, David Bateman, 2003, Geoff Bryant