Dice is fairly accurate is saying that
.......
"anyone reading here has answers to all of these questions off of the top of their head, they probably do not have the time to answer them all in a Tomatoville thread."
That is for sure! If I had the time I could talk about these topics 'off the top of my head', but I would rather have case studies of my own....backed up with examples of professionals that I have known...or internet quotes...or textbook references. Many questions have come up via the TVille topics and threads that begged tomato breeders as myself to offer definitive answers. I have had the experience of working without a precise genetic blueprint of the many genes that play into developing new varieties. It is mostly breeding with a working knowledge when one is in the field or greenhouse making crosses and/or selecting traits in the filial generations.
Dice mentioned this book:
The Tomato Crop: A scientific basis for improvement (World Crop) by J. Atherton and J. Rudich (Hardcover - Dec 31, 1986)
Buy new: $629.00
9 new from $467.03
10 used from $181.50
Even at $181.50 that is a pricey book! I tried to see if a book was in the greater King County/Seattle area libraries..to no avail. I read the sample pages just as Dice did. The problem I see with this book is......it is 25 years old with examples going back much further. I am now just a few days short of 66...and that book came out when I was 40....and of course, I would have had no access to it then. Much of what is in the book is what I learned by myself or from tomato breeders I have met over the many years. It is almost a history book!
Tomato breeders know that getting flavor and determinate growth has been almost insurmountable. I have exceptions to the rule, but not enough time to pursue a written report of the ups and downs of that. Rest assured that if you try to meld a Brandywine with a determinate...your first efforts will likely be dismal.
Tomatoes have 12 pairs of
chromosomes and we have way too many genes to pack into those 12 highly linked chromosome parts. With repeated breeding I think I have had translocation switches which allowed unusual pairings of traits. It does no great service to work with paired chromosomes that are identical. Working with a hybrid flux whereas the chromosomes are dissimilar in repeated generations of seed saving....the opportunities for favorable translocations are enhanced.
Once a variety is relatively true breeding (stable) those new chromosome pairings are identical. Translocations that occur after the variety is true breeding often occur at identical weak points far from the centromere, resulting in translocations that are equivalents of the original chromosome. If a translocation occurs at a different point...the resultant embryo has a chromosome that has an addition or a deletion for that gene and/or several genes, making for a mutation that may or may not be viable in a first generation...let alone when it becomes homozygous in an F-2 plant.
Plant breeding ought to be straight-forward...but it seems to be more successful in a field of art....observation, memory, trial and error, and stubbornness. It is in the awe of the unknown rather than the expectation of definitive results that drives me.
Tom Wagner