F1 Hybrid Theory ?

[MagpieDi]

Could someone kindly explain the basics of F1 hybrids.

Due to my non-labelling (yet again   ) I've got a bag full of mixed sunflower seedheads, and now realise that one type I grew was an F1 hybrid.
Will that particular seed be sterile, or just not grow true to type??

Many thanks

Di

[Palustris]

It is very simple really. An F1 hybrid is created when under carefully controlled conditions two forms of a plant are crossed, ie pollen from one is tranferred to the other. The resultant seeds produce plants which are the first cross between the parents.
If you then allow open pollination between the resultant plant and another, as in a garden situation then the seeds produced, whilst viable, could revert to any of the previous generation of parents or produce something different. So your Sunflower seeds could produce a whole ruck of different sunflowers.
There you are , clear as mud.
Now ask about f2 hybrids.

[MagpieDi]

Thanks Eric, simple !!    So still worth germinating then...... great!!

Now, F2's please !!  

[Palustris]

I will leave that to John or Hugh I think.

[Hugh_Jones]

Eric`s reply about F1 hybrids is technically correct, but in practice many hybridisers, in order to produce the best results with perfect uniformity will re-hybridise the original F1 hybrids, and even back-hybridise with the original parents, and the resulting seed is still sold as F1 hybrid.  The resulting seed produces plants of virtually complete uniformity, but despite this the actual gene make-up of the plants is variable

F2 hybrids are the progeny resulting from the inter-hybridisation of F1 hybrids, but the hybridising of plants with variable gene make-up, however uniform in habit the parents are, can result in quite considerable variations in the resulting progeny as to size and vigour of growth and flower colour and characteristics.

I`m afraid that this is a rather simplified answer, but the actual specifics would probably get a bit boring.

[Hugh_Jones]

P.S. Of course, I forgot to mention the most explanatory fact of all, namely that the `F` is merely an abbreviation of `Filial generation`, so F1 is First Filial generation, F2 is second Filial generation.  Thankfully we haven`t got around to F3 yet

[MagpieDi]

Many thanks for that easily digestible info Hugh!

b.t.w. Little chance of finding it boring. As a cricket enthusiast, avid reader of Wisden, and a Geoff Boycott fan to boot, I am boring personified!!    
Yorkshire's 1975 season statistics.........sheer bliss !