Agricultural Sciences

Main Content

The School of Agricultural Sciences offers a graduate program leading to the Doctor of Philosophy (Ph.D.) degree. This degree is designed to provide students with an interdisciplinary doctoral education in the physical, biological and social sciences that enhances, regulates and sustains agriculture, food and forestry producers, industries and agencies. This degree will prepare Ph.D. in Agricultural Sciences graduates to teach and conduct research and outreach at universities and community colleges, and for careers in the corporate, private and government sectors.

Doctor of Philosophy (Ph.D.) in Agricultural Sciences


All applications to the program must include a Graduate School on-line Application available at, a statement of interest, college transcripts, three letters of recommendation, GRE scores including verbal and quantitative, and may include a financial assistance form. In addition, this Program requires a non-refundable $65 application fee. Criteria for admission include: an official transcript, letters of recommendation, grade point average (must meet the SIU Graduate School minimum 3.25 GPA in graduate work), and GRE scores. The Graduate Committee of the School of Agricultural Sciences must approve admission to the Ph.D. in Agricultural Sciences program. Ph.D. students will be selected on a national and international competitive basis.

Students may be admitted to the doctoral program with a Bachelor’s, a Master of Science or a Master of Arts degree in Agriculture, a discipline within the SIUC School of Agricultural Sciences, or a closely related field (such as Biology, Botany, Natural Science, Rural Sociology, Economics, or Environmental Science). Upon nomination of the master’s committee and upon approval by the School of Agricultural Sciences doctoral program committee, exceptional M.S. students may be allowed accelerated entry to the Ph.D in Agricultural Sciences program.

Students admitted under direct or accelerated entry to the Ph.D. in Agricultural Sciences program are subject to all existing requirements for the doctoral degree; the admission/advisory committee for the student may add extra requirements based on the student’s background.    


Each doctoral student in the School of Agricultural Sciences must successfully complete a common core of research methodology courses, including a two-semester sequence of graduate level statistics courses for four to five credit hours each, followed by a three to four credit hour graduate level experimental design course. Students also will be required to take a three-credit hour course in Research and Teaching Communications, two semesters of graduate seminar, and 24 credit hours of dissertation credits. There will be an additional minimum of 20 credit hours of structured courses appropriate for each student’s area of emphasis. The student’s graduate advisory committee must approve these courses. Emphasis areas include: Agricultural Economics, Agricultural Systems Technology, Agricultural Education, Animal Science, Biotechnology, Crop Science and Environmental Management, Forestry, Horticulture, Plant Pathology, and Renewable Energy.

All Ph.D. in Agricultural Sciences students in the program will be required to teach or assist in teaching at least two courses within the School of Agricultural Sciences while in the program. This requirement is regardless of the form of stipend of the student, i.e. if a student is on a research assistantship throughout their tenure in the program, they will still be required to teach or assist in teaching courses.

There is no minimal credit-hour requirement beyond the core, the area of emphasis, and the Graduate School’s residency and dissertation requirements. A student in consultation with their major professor will prepare a program of study, including courses in the student’s area of emphasis, by the end of the second semester of residency. This plan of study, when approved by the student’s advisory committee, will be filed with the Director of Graduate Studies for the School.

Ph.D. in Agricultural Sciences Candidacy

By the end of the second semester in residence, students must have chosen an area of emphasis and formed a graduate advisory committee to approve their coursework and oversee their dissertation research. The graduate advisory committee will consist of at least five graduate faculty members, with the majority from within the School of Agricultural Sciences and no more than three members from one program. The committee chair will be the student’s major professor and must be a member of the School of Agricultural Sciences faculty.

To be admitted to candidacy, the student must have completed the Graduate School’s 24-credit hour residency requirement within four calendar years, plus the core and emphasis area coursework that was approved by their graduate advisory committee. This should take the student three to four semesters, depending on whether they had any graduate-level research methodology courses during their Master’s degree. At this time, they will take both written and oral preliminary examinations designed and administered by the student’s graduate advisory committee. These exams will each have two parts. One will focus on the student’s knowledge of the research methodology core and the second part will focus on the student’s chosen area of emphasis. If the preliminary examinations are not passed, a student must wait a minimum of three months for the second and final attempt to pass the exam.

After passing the written and oral preliminary exams and with an approved dissertation proposal, the student will be admitted to candidacy. The Graduate School requires that Ph.D. in Agricultural Sciences students fulfill all degree requirements within five years of admission to candidacy or they may have to retake their preliminary exams.

Dissertation and Dissertation Examination

By the beginning of the fifth semester of residence, the students will present to their graduate committee a dissertation research proposal. The student’s committee must approve the proposal by the end of their fifth semester of residence. At this time, students must present their dissertation proposal verbally in the form of a graduate seminar. All faculty members in the School of Agricultural Sciences, the student’s graduate advisory committee, all other graduate students in the School, and appropriate individuals from industry groups in southern Illinois will be invited to these seminars. Following the seminar, the student will meet with their graduate advisory committee and will be asked to defend the substance and methods of the proposed research.

The student’s graduate advisory committee will monitor the student’s progress on the dissertation. When the dissertation is completed to the satisfaction of the graduate advisory committee, the committee will administer a final oral exam that will focus on defense of the dissertation. When the dissertation and final oral exam are successfully completed, the student will be recommended to the Graduate School for the doctoral degree.