Why did Vavilov think that the study of the traits of wild plants, which are the progenitors

Why did Vavilov think that the study of the traits of wild plants, which are the progenitors of cultivated forms of plants, is very important?

The study of wild plants is very important in our time. Wild plants are adaptable to their environment. They are well protected from drought, heat, wind, pests and other factors. Cultivated plants generally do not have these properties, since their goal was to produce the maximum number of fruits. Now the study of wild plants allows us to create new varieties by hybridization or genetic engineering. This way we get high-quality cultivated plants that become more resistant to environmental factors.