The first thing to think and do research in agriculture is to find theories related to your underlying and constructed statement problem or objective. The important of theory concept or theoretical framework is to gather information and tangible idea to come up with your research. The research will systematically proves theory.
Related literature and studies in agricultural research is vital to reflect your underlying research and theories of recall ideas of what variables are involve and it will contribute you knowledge on how method should you used. Agricultural research methodology usually used quantitative research. Most of research are dealing with experimental.
Here is the Sample study in conducted in Africa entitled "Improved Rice in Senegal"
In Senegal, researchers screened hundreds of Asian short-duration rice varieties to promote double cropping in areas where only one rice crop was grown before. In 1994, the variety that performed best in local conditions was released under the name Sahel 108. It was an instant success and not just for double cropping. Farmers also found it useful during the rainy season. The extra month of planting time provided by the short-duration variety proved to be a life-saving advantage for those who did not get inputs in time or who were sick during the critical period.
More details on Sahel 108 can be found in the 1996 Annual Report of the West Africa Rice Development Association (WARDA)