Two forage-types ['Kentucky 31', 'Georgia 5' (GA-5)], two dwarf-types ('Bonsai', 'MIC18
'), and seven nondwarf tuff-types ('Arid', 'Falcon II', 'Houndog V', 'Mustang', 'Phoenix', 'Rebel II', 'Rebel Jr.') were included in these studies.
Mustang (a tad-type cultivar), and MIC18 (a dwarf, turf-type cultivar) under well-watered conditions.
However, RLD of MIC18 was lower than that of Mustang at 30 to 60 and 60 to 90 cm.
Soil depth (cm) Cultivar 0-30 30-60 60-90 Kentucky-31 1.48 a([dagger]) 0.64 a 0.14 ab Mustang 1.68 a 0.67 a 0.19 a MIC18 1.23 a 0.38 b 0.04 b ([dagger]) Means followed by the same letter within a column were not significantly different (P = 0.05).
Root dry weight was reduced by 17, 12, 16, and 19% for MIC18 and by 12, 8, 8, and 15% for Kentucky-31 at 7, 14.
MIC18 had significantly higher SRL values than Kentucky-31 under well-watered conditions and at 28 d of soil drying (Fig.
In our study, the extent of root hair development at the basal 5 cm of nodal roots was similar for MIC18 and Kentucky-31 under either well-watered or drying conditions.
Root water potential was lower at 7, 14, and 21 d of drying than that under well-watered conditions for both Kentucky-31 and MIC18 (Table 2).
Root water potential ([[Psi].sub.root]) and turgor pressure in response to soil drought stress for Kentucky-31 and MIC18.
Days after treatment 7 Cultivar Treatment [[Psi].sub.root] Turgor MPa Kentucky-31 Well-watered -0.31 b([dagger]) 0.24 a Drought -0.83 a 0.17 b MIC18 Well-watered -0.40 b 0.28 a Drought -0.90 a 0.09 c Days after treatment 14 Cultivar [[Psi].sub.root] Turgor MPa Kentucky-31 -0.50 c 0.39 a -3.85 b 0.09 b MIC18 -0.68 c 0.47 a -4.11 a 0 c Days after treatment 21 Cultivar [[Psi].sub.root] Turgor MPa Kentucky-31 -0.35 b 0.27 a -5.87 a 0 b MIC18 -0.28 b 0.35 a -5.88 a 0 b ([dagger]) Means within a column followed by the same letters were not significantly different based on a LSD test at P = 0.05.
Severe cortical cell collapse, as evidenced by air space formation, was observed at 14 and 28 d of dry down for both cultivars, causing root shrinkage of a similar extent for Kentucky-31 and MIC18 (Fig.