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Research Project: Genetic Improvement of Small Grains for Biotic and Abiotic Stress Tolerance and Characterization of Pathogen Populations

Location: Plant Science Research

Title: QTL linkage analysis and identification of quantitative trait loci associated with freeze tolerance and turf quality traits in St. Augustinegrass

Author
item KIMBAL, JENNIFER - North Carolina State University
item Tuong, Tan Duy
item ARELLANO, CONSUELO - North Carolina State University
item Livingston, David
item MILLA-LEWIS, SUSANA - North Carolina State University

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2018
Publication Date: 5/1/2018
Citation: Kimbal, J., Tuong, T.D., Arellano, C., Livingston, D.P., Milla-Lewis, S. 2018. QTL linkage analysis and identification of quantitative trait loci associated with freeze tolerance and turf quality traits in St. Augustinegrass. Molecular Breeding. 38:67.

Interpretive Summary: This paper presents the first linkage map for St Augustinegrass. One hundred sixty single sequence repeats (SSR) were located on the chromosomes of this important turf species. SSR’s are small segments of DNA that can be associated with traits of interest (in this case winter kill, spring green up and other traits described in the manuscript). These DNA segments can be used to identify germplasm with positive traits for use in breeding programs. This study, for the first time, provides a basis for a St Augustinegrass improvement program based on DNA marker technology.

Technical Abstract: St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] is a warm-season turfgrass commonly grown in the southern United States. In this study, the first linkage map for all nine haploid chromosomes/comprising all chromosomes of the species was constructed for cultivar ‘Raleigh’ and cultivar ‘Seville’ using a pseudo-F2 mapping strategy. A total of 160 simple sequence repeat markers were mapped to nine linkage groups (LGs) covering a total distance of 1176.24 cM. To demonstrate the usefulness of the map, quantitative trait loci (QTL) were mapped controlling field winter survival, laboratory-based freeze tolerance, and turf quality traits. Multiple genomic regions associated with these traits were identified. Moreover, overlapping QTL were found for winterkill and spring green up on LG 3 (99.21 cM); turf quality, turf density and leaf texture on LG 3 (68.57-69.50 cM); and surviving green tissue and regrowth on LGs 1 (38.31 cM), 3 (77.70 cM), 6 (49.51 cM), and 9 (34.20 cM). Additional regions, where QTL identified in both field and laboratory based/controlled environment freeze testing co-located, provided strong support that these regions are good candidates for true gene locations. These results present the first complete linkage map produced for St. Augustinegrass, providing a template for further genetic mapping. Additionally, markers linked to the QTL identified may be useful to breeders for transferring these traits into new breeding lines and cultivars.