Education qualification is nothing do with the finalisation of marriage. You should look for his family background, financial position and his habits and attitudes should be matching with yours. Then both of you can have a personal chat regarding your desires, ambitions and goals. If both of you are on similar lines and if both of you can have an adjustable mentality, you can go ahead. You need not think about what is the educational qualification. In your case, both of you are very well educated and both of you can get good jobs. So there should not be any problem if all other accepts are acceptable to you both.
Coming to your question regarding M.Tech and PhD. In any subject PhD is the top qualification and it is a Doctorate degree. M. Tech is a PG course and after M.Tech, you can go for your PhD in your subject.
Agricultural discipline is more a science-based course and PhD in that subject is based on the research carried out by the candidate. This is a specific degree given to an individual based on the quality of the work carried out. There are no written tests for this. Only a Thesis is to be submitted in which his original research work is to be presented with the information about his scientific publications. This book will be adjudicated by the experts in the subject. Then a viva will be conducted and then the degree is awarded. M.Tech is awarded based on the written exams and project work carried out and it is a professional degree. Both are different fields and we should not compare each other. However, PhD is the highest qualification one can get.