The bluegrasses, also commonly referred to as meadowgrasses, are one the most economically important genera of the Poaceae ( Huff, 2010 ; Soreng and Barrie, 1999 ). Kentucky bluegrass ( Poa pratensis L.) is the botanical-type species for the
Kentucky bluegrass ( Poa pratensis L.) is a facultative apomictic cool-season perennial grass species widely used for forage and turf in the United States and Canada ( Huff, 2003 , 2010 ). Although sexuality in kentucky bluegrass can be variable
-adapted tobacco callus J. Heilongjiang August Firet Land Reclamation University. 9 7 9 Zhang, Y. Li, Z. Li, M. Du, X. 2004 The study of complex alkali–saline stress on four varieties of Poa pratensis Chinese Agricultural Science Bulletin. 20 209 213
Kentucky bluegrass ( Poa pratensis L.) is a popular turfgrass species throughout its adaptive range. It typically produces a dense stand of turf with dark green color, high overall turf quality, and a wide range of disease tolerance. This makes
Kentucky bluegrass ( Poa pratensis L.) is a perennial turfgrass species that is widely adapted to many distinct environments. The extensive rhizome system of Kentucky bluegrass gives it the ability to tolerate and recover from many environmental
Seeds of a Kentucky bluegrass cultivar (Poa pratensis 'SD Common') and two native buffalograss (Buchloe dactyloides) strains, Texas (TX) selection and North Dakota (ND) selection, were tested for their germination tolerance to increasing levels of NaCl at 0, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, 3.2% in solution. Both the TX and ND strains of buffalograss exhibited a high degree of salt tolerance with the upper limit of seed germination at 2.8% NaCl (2% to 7% germination after 6 days). At high NaCl concentrations, however, percent seed germination was much greater in the ND strain than the TX strain of buffalograss. For instance, seed germination at 0.8% NaCl was 90% in ND strain and 53% in TX strain as compared to the control. Kentucky bluegrass was least tolerant to NaCl with the upper limit of seed germination at 0.4% NaCl (14.7% germination in 6 days). Seed germination in Kentucky bluegrass was completely inhibited at 0.6% NaCl.
The germination of Kentucky bluegrass, (Poa pratensis L.), seeds is profoundly influenced by two light reactions. One, the phytochrome reaction (P), is promotive, and the other, the so-called “high-energy reaction (HER)”, is inhibitory to germination. The level of germination displayed in 14 days as the resultant of these two opposing reactions is appreciably influenced by temperature.
In darkness, the seeds germinate well at certain temperature alternations but not at constant temperatures. At 15-25°C, the promotive effects of temperature alternation are accomplished in the first 5 to 6 cycles. The promotive effects of alternations are displayed in darkness when the daily period at 25° is between 4 and 14 hours.
Brief daily high-intensity fluorescent illuminances (approximately 4,000 ft-c) during otherwise continuous darkness at constant 20°C induce high germination in most lots. Continuous medium-to-high intensity illumination (approximately 1,200 ft-c) very weakly promotes germination and in potentially promoted seeds inhibits germination to about the level of the dark controls.
Inhibitory effects of continuous light on potentially promoted seeds are best displayed at 20°C constant although, in ‘Newport’ they are observable at 15-25°. The inhibition of ‘Newport’ at 15-25° is to a level below that of the dark controls but above that caused by prolonged illumination at 20°.
Thus conditions most promotive to germination are 15-25°C alternations and brief daily illuminances of high intensity. Simultaneous application of these 2 conditions causes higher germination than when either is applied alone and in one lot of ‘Newport’ the effects are strikingly additive.
A trial of 38 cultivare of Kentucky bluegrass (Poa pratensis L.) demonstrated genetic differences to an infestation of bluegrass billbug. The correlation coefficient between injury ratings and billbug larval density in sod samples was r = 0.73. Thatch accumulation was not significantly correlated (r = 0.31) with billbug density.
In a field test of 25 Kentucky bluegrass cultivars (Poa pratensis L.) “common types” were generally more drought tolerant than recently introduced turf types. ‘Code 95’, a common type, and ‘Merion’ exhibited high drought resistance and produced turf of good color, texture, and density. Turf mowed at 3.8 cm was more resistant to drought than turf maintained at 1.9 cm.
Bensulide [0,0-diisopropyl phosphorodithioate S ester with N-2-mercaptoethyl) benzenesulfonamide] at 13.6 kg/ha reduced sod transplant rooting of ‘Park’, ‘Merion’, and ‘Baron’ Kentucky bluegrass (Poa pratensis L.) when applied either to sod or sodbed. Prosulfalin [N-[[4-(dipropylamino)-3,5-dinitrophenyl] -S,S -dimethylysulfilimine] at 2.3 kg/ha applied to the sodbed reduced sod transplant rooting of ‘Park’ and ‘Baron’. Benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine) at 2.3 kg/ha reduced rooting of ‘Baron’ when applied to the sodbed. Sod transplant rooting of ‘Baron’ was significantly reduced by siduron [l-(2-methylcyclohexyl)-3-phenylurea] at 13.6 kg/ha, oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropyoxyphenyl)-△2-1,3,4-oxadizolin-5-one] at 4.6 kg/ha, prosulfalin at 2.3 kg/ha, and benefin at 2.3 kg/ha when applied to sod prior to transplanting. ‘Merion’ and ‘Park’ were not influenced by these treatments. Regardless of herbicide treatment, ‘Baron’ had a lower sod transplant rooting strength when compared to ‘Park’ and ‘Merion’.