In most cases, I don't know which traits are dominant, and which are recessive. I just know which traits I want to keep around.
I use "normalization" in the statistical sense. Sorting the beans to get them all back to the same starting scale: 20 seeds from each variety. That's my way of keeping some of each type in the population, and of identifying new hybrids. I also plant bulk beans, intending them primarily for feeding my community. In that population, the plants that produce the most (harvested) beans end up dominating. "Balancing" the population would be another great word, that might appeal more to non-statisticians.
In my garden, common vulgaris beans are primarily inbreeding, with only like 1 in 200 crossing. Other gardens might have up to 5% crossing. So with beans it's really easy to maintain recessive traits over the long term. Black seems to be the most common dominant trait in bean seed coat color. Over the years I have done a lot of selection against black beans.
While my beans cross at a very low rate, I sort them by hand, to try to identify hybrids. Any suspected hybrids that I find go into the stash to be planted next year. Then the hybridized-genetics are reorganizing themselves for 5 to 7 generations, so lots of new varieties can show up. Once a recessive trait shows up, and I select for it, then it's 99.5% likely to remain in the population each year after that.
In out-crossing crops like corn, it is easy to select for recessive traits, by selecting against dominant traits in every generation. It's much harder to select for dominant traits, cause recessive traits can be masked and then show up many generations later.
Many of the hybrids that I have worked with were between pole beans and bush beans. I aim for my population to be bush beans only. So I do a tremendous amount of culling for growth habit.
I have not been selecting beans for flavor. How do I cook a pot of beans, when an individual plant might only produce 20 seeds? I suppose that I could grow and harvest by type, and get enough to cook a pot of beans.
For me, the most important traits in melons are quick vigorous growth and early flowering. That is due to the short-growing season. A corollary is that smaller fruits tend to mature weeks earlier than larger fruits, so it's to my benefit to select for smaller fruits.