Jellybean tomato plant not producing
 

I have a jellybean tomato plant that I grew from Ferry Morse seeds. I
have just one plant. It's about 3.5 feet tall and supported by a wire
cage. The others didn't survive. They are rather difficult to grow from
seed. It looks green and healthy. It has a decent number of little
yellow flowers and has been flowering for more than a month I think.
But it has not one tomato. Also, some of the flowers just fall off by
themselves. They break off the stem easily. I've been watering it every
day and I gave it fertilizer a couple of times. I also used a little
sulfur a couple of times since this is in southern California and the
soil is alkaline. Do you think maybe the high heat has prevented
tomatoes from forming? Do I need more than one plant to polinate? I
have another tomato plant with regular size tomatoes and it has
produced a lot of tomaoes.