I am not able to answer your question but I think tomatoes like runner beans
are perennials-it's just more convenient to grow them as annuals.
Waiting for flak!
Regards
David T
"gary croft" wrote in message
...
HI all i cant recall my botany lessons and i was wondering what is the
actual mechanism that triggers the death of an annual is day length, temp
or production of seed? or a combination of those factors?

The reason i am asking is i am looking to start to breed varieties of
fruiting plants for example tomato. If i get a particular plant i want to
keep as stock i would like to keep the plant alive for example
hydroponically with artificial conditions temp light etc until such a
point
i can develop the seed to see if it hasnt been cross pollinated. So i was
wondering if i kept the temp and daylength up and not allow it to set seed
could it live until the following season? just a little project i want to
work on any comments please?

Kind Regards,

Gary