How does the degradation of technoscience most significantly affect class dynamics?

Your question refers to the Octavia Butler novel Parable of the Sower. You might get some insight into the themes of the novel by reading and understanding the eponymous chapter of the Bible's Book of Matthew (Matthew 13:1–9 and 13:18–23).
The term "technoscience" refers to the convergence of science and technology. That is, it puts science into context, gives it meaning, and gives it social frames of reference. In Octavia Butler's novels, her characters frequently possess some special ability or tool—a technological artifact or body of scientific knowledge—around which the plot revolves. In Parable of the Sower, this tool is hyperempathy, or the ability to feel everyone else's pain as it really is.
Class dynamics are the ways people of different social status interact. In the social science literature, including Marxist theory, class is a function of material conditions and history. In Parable of the Sower, class is also a function of race.
When technoscience breaks down, we would expect class conflicts to both accelerate and sharpen. That is, people would tend to judge people quicker based on their perceived class, and the consequences of this judgment would tend to be more severe. That's because technoscience, when it's working well, blunts class distinctions by giving people of different classes the same tools with the same powers. It's a leveling effect. When that's taken away, class distinctions re-emerge, and because people don't have the mediating influences of technoscience any longer, those distinctions are more important, and people are more sensitive to them.
An example of this in Parable of the Sower is the outlawing of interracial relationships. One consequence that flows from this is the murder of Lauren's family, from which the rest of the plot flows. So, in a sense, the entire novel is about class dynamics after the breakdown of technoscience.