Evaluation Of Heat Tolerance And Overseeding In Cool-Season Turfgrass

As a cool-season annual turfgrass, the present researches of annual bluegrass concentrate on the turfgrass management, while study on other aspects is little so that, its use still needs to be developed. The area of southern the Yangtze River is hot in summer, seriously harmful to normal growth of cool-season turfgrass. Using a wild-type annual bluegrass in NanJing (’Njpl’) and rough bluegrass’Sabre’, annual ryegrass’Panterra’, perennial ryegrass "Premier" as materials. The study was conducted to investigate morphological index and physiological-biochemical index of four cool-season grasses under high temperature stress. Results showed that1) different temperatures caused different effect on four turfgrass’s physiological indexes and antioxidant enzyme activity: under30/25℃(day/night) stress there’s no difference, under40/35℃(day/night) stress turf quality (TQ), relative water content (RWC) and CAT decreased with threatened time increasing, relative electric conductivity (EL) and malondialdehyde (MDA) increased, SOD activity increased firstly and then decreased;2) annual bluegrass has a lower rate of change of TQ, RWC, SOD and CAT, and a higher rate of change of EL and MDA. The heat tolerance of annual bluegrass is worse than rough bluegrass and perennial ryegrass, but better than annual ryegrass. CAT might play a role in the heat tolerance of turfgrass.Overseeding could be evergreen for warm-season turfgrass. It has be widely applied in turfgrass management in southern China. The commonly used varieties of overseeding in the region are perennial ryegrass and annual ryegrass, while other varieties are relatively few. This study of annual bluegrass overseeding is of great importance due to the evergreen characteristic during winter and early spring. Taking a wild-type annual bluegrass in NanJing (’Njpl’) and annual ryegrass’Panterra’, perennial ryegrass’Pinnacle’as research materials, overseeding experiment was conducted evaluate of the effects of the three varieties. The result showed that annual bluegrass maintained green for a long period during overseeding with good turf quality during spring time. It would not prevent Manila grass turning green.Overall performance of annual bluegrass was better than the other two common overseeding varieties.