Short Answer: No, It’s not enough.
Long Answer: Not enough at all, even if you are going to study in English taught course, the thing which you will learn on Duolingo will help you to know the basic grammar and basic day to day conversations. By basic, it’s really pretty basic. Like I am eating an apple and he is eating an apple kind of stuff, so if you won't do any other thing to learn the language and only use Duolingo, you can say only these kind of basic sentences which according to CEFR would fall under A1 and in some advanced Duolingo levels A2, more than that Duolingo can not offer at the moment. I am Duolingo Global ambassador for 2 years, there are some promising features like Duolingo Stories, Duolingo Podcast and Duolingo events which can be used to fulfill the gap. You can connect with me and learn a language for free over Duolingo.
I have completed the complete 5 levels/ checkpoints offered on Duolingo when I was learning the language, they have updated them now. I was also attending the physical class, Duolingo for me was kind of addition to my language learning, but it was never a substitute for a full-time teaching or former teaching options. Even to communicate with a native person would need a proper environment and a little bit of practice, which is not possible at the moment with Duolingo. You can find a Duolingo Event group where you can practice with other Duolingo users. Listen to some podcast to get familiar with the german culture and some common practices by the natives, which are also important aspects of learning any language.
Use Duolingo as a tool to enhance your learning experience, but it won’t be enough on its own to use it in real-world out there, for that, you need some more resources like books, online materials, etc for your MS in Germany for English teaching course. For German taught courses there is no substitute other than learning professionally up to C1 level and appear for the required exams to get the proof of your required language proficiency.