Yes, probably they did it, because Minsk region where I've been living for 20 years so far is a famous agricultural area and more than a half of all people here have got their own country houses (dacha) where we grow tomatoes and other vegetables for food and for selling at farmer markets every year.
Back in pre-1917 era there was a Russian Empire here, but the country your grandparents had left had also another name which is the same now - Belarus.
I was lucky to buy an old book dated in 1915 by the famous Belarusian (Russians called him Russian as well :-) agriculturist Mikhail Rytov who was the main keeper of vegetable collection of Agricultural Academy in small belarusian town Gorky near Russia. There are a lot of interesting info with pictures about gradening tips and popular varieites grown in Russian Empire before October Revoluton of 1917.
They mostly grew German, English, American and other foreign tomato varieties. The number of local varieties were quite limited because tomato were still no so Russian (and Belarusian as well) vegetable. Slavic people prefered to grow cabbage, onion, turnip and grains which they can grow without having greenhouses (a fairly very expensive thing for quite poor people).
These foreign tomato varieites were popular in 1915 in Russian Empire: King Humbert, Spark's Earliana, Koenig der fruehen, Koenigin der fruehen, Allerfruehester roter, Pomme rouge.
I believe you can still find and grow both King Humbert and Spark's Earliana now.
It'd be a very difficult to find a very old Russian tomato varieties now because in the Communist era (1917-1991) we had no tradition to save seeds and keep heirlooms. Everything had to be collective or owned by the State. In Soviet Union people had been working in collective farms (kolkhoz) where they grow vegetables not for their families in their gardens but for the whole country. These kolkhozes were supplied by seeds and machines by the State.
There was also no major tradition to breed and improve vegetable varieites by single gardeners. Since 1920s there were a growing amount of Agricultural Institutes and AES which have been doing this work.
And only in 1970s when more and more Soviet people got their own dachas from the State they started experiments with crosses of different varieties and re-enter the seed saving time like in pre-1917 Russian Impire era.
So as I said it much here, please, don't try to find many Russian (Soviet) heirlooms. We just don't have them. We have only commercial and non-commercial vegetable varieties. Probably you have better chances to find Russian heirlooms via old Russian emigrant families abroad.
Most of our people are still think that if they maintain the same vareity during more than 5 years there will a major loss of its yield, fruit size and sometimes even a taste. But I always try to teach them not to be like rednecks from the backwoods
