The effects of different plant growth-promoting rhizobacteria (pgpr) applications on turfgrass performance of perennial rye grass (Lolium perenne L.)

This research was carried out to investigate the effects of different bacteria groups on turfgrass performance of perennial ryegrass (Lolium perenne L.)' in Kelkit district of Gümüşhane in North East Turkey in 2017 and 2018. The treatments included: Seven different bacteria group inoculations [i.e. (B1: RK-1977 + RK-1978 + RK-1979), (B2: RK-79 + RK-504 + RK-1984), (B3: RK-92 + RK-540 + RK-1980), (B4: RK-1981 + RK-1982 +RK-1983), (B5: RK-491 + RK-716 + RK-1130), (B6: RK-79 + RK-92 + RK-1105), (B7:RK-79 + RK-92 + RK-491 + RK-532 + RK-1105 + RK-1108)] and a control (without bacteria inoculation). The effects of different bacteria groups' inoculations to the seeds of perennial ryegrass on cold resistance, number of tillering, texture, cover, weed ratio, color and turf quality of perennial ryegrass were investigated in this study. The study design was a randomized complete block with eight treatments replicated three times. Different bacterial groups have positive effects on cold resistance, number of tillering, texture, cover, weed ratio, color and turf quality of perennial rye grass. B1 bacteria group in terms of cold resistance; B2 and B7 bacteria groups in terms of number of tillering; all bacteria groups in terms of texture; B7, B5 and B6 bacteria groups in terms of covering; B1, B3 and B5 bacteria groups in terms of weed ratio and B7 bacteria groups in terms of color and turf quality have the best values. The B1 bacteria group the most ideal application was in "very good" level in terms of cold resistance, while the control group was in the "middle" level. B2, B3, B4 and B7 bacteria groups the most ideal applications were in the ''frequent" level in terms of tillering number, while the control group was in the "middle" level. The B7 bacteria group the most ideal application increased the tillering number by 171% in compare with the control group. Control and B4 bacteria group were in the "thin" level in terms of texture, all other bacteria groups were "middle" level. B5 bacteria group the most ideal bacteria application increased the texture by 65% in compared with the control group. B7 bacteria groups the most ideal application were in the "high density" level in terms of cover, while the control group was in the "middle" level. B1, B3 and B5 bacteria groups the most ideal applications were in the "no weed" level in terms of weed ratio, while the control group was in the "middle" level. Control was in the "light yellow green" level in terms of color of turf grass, while the all bacteria groups were in the ''green" level. B7 bacteria groups the most ideal application were in the "very good'" level in terms of turf quality, while the control group was in the "bad" level. According to the results of the study, B7 (RK-79 + RK-92 + RK-1105 + RK-1108 + RK-491 + RK-532) bacteria group was more effective than other applications, when all these parameters were evaluated together. Keywords: Bacteria, Turfgrass, Perennial rye grass, Cold resistance, Color.