Theses and Dissertations

Issuing Body

Mississippi State University


Morrison, Jesse I.

Committee Member

Tomaso-Peterson, Maria

Committee Member

Baldwin, Brian S.

Committee Member

Lu, Shien

Date of Degree


Document Type

Graduate Thesis - Open Access



Degree Name

Master of Science (M.S.)


College of Agriculture and Life Sciences


Department of Plant and Soil Sciences


Cattlemen in the southeastern United States widely plant annual ryegrass [Lolium perenne L. spp. multiflorum (Lam.) Husnot] (ARG). It is often planted earlier than the recommended window. This exposes juvenile stands to increased pressure from gray leaf spot (Pyricularia oryzae Cavara) (GLS), causing stand loss. This study was designed to screen for resistance to P. oryzae in two ARG genotypes, Vertyl and a heat-tolerant germplasm (HTARG5) with the objective of developing a crossbred population to be improved using restricted, recurrent phenotypic selection. Experiments were conducted from 2021 – 2022. Disease severity (DS) was assessed 3wk after inoculation with P. oryzae. Vertyl had a significantly lower DS in the preliminary screenings compared to the other genotypes. In experiments 3 and 4, mean DS of Vertyl, HTARG5, and Marshall was not significantly different. These results confirm Vertyl has greater resistance to GLS than HTARG5 and can be a candidate for disease resistance breeding.

Available for download on Thursday, August 15, 2024