Tall fescue (Festuca arundinacea Schreb.), a major cool-season grass species, is widely utilized as forage and turfgrass. The growth and development of tall fescue is severely litmited by heat stress in transitional and warm climatic regions, therefore, the heat tolerant cultivars are in great need. The study of plant physiological responses to heat stress and identification of molecular markers linked to heat toletance would promote the efficiency of traditional breeding programs in developing heat toleranct cultivars.  

A research team led by Prof. FU Jinmin from Wuhan Botanical Garden analyzed association of heat tolerance-related functional traits in 100 diverse tall fescue accessions from 33 countries grown in greenhouse and controlled growth chambers.  

Five growth and physiological traits, including turf grass quality (TQ), survival rate (SR), leaf chlorophyll content (CHL), evapotranspiration rate (ET), growth rate (GR) showed significant genetic variations and significant mutual correlations in response to heat stress in tall fescue.  

The population structure, relative pairwise kinship, and marker-trait association by mixed linear model (MLM) were statistically analyzed based on simple sequence repeat (SSR) markers. A total of 1010 SSR alleles were amplified from 90 SSR markers, two subpopulations were identified based on the Bayesian clustering approach model, but no obvious kingship was detected. By MLM as the best model for association analysis, 97 associations and 67 associations were identified for five heat tolerant traits respectively in greenhouse trial and growth chamber. In the two trails of this study, due to the different experimental conditions of heat stress, only 2 SSR alleles associated with GR and ET were identified in response to heat stress.  

The identification of marker alleles associated with functional traits enlightens heat tolerance genetic pathway study and promotes heat-tolerant tall fescue breeding.  

This research was supported by the General Program from the National Natural Science Foundation of China, the National High Technology Research and Development Program from “863” plan of China, and the Special Fund of Industrial (Agriculture) Research for Public Welfare of China. Relevant results were published in BMC Plant Biology entitled “Association of SSR markers with functional traits from heat stress in diverse tall fescue accessions”.