Kentucky Bluegrass Germination and Early Seedling Growth Under Saline Conditions

Abstract

Salinity tolerance of five Kentucky bluegrass (KBG) (Poa pratensisL.) cultivars, Mystere, BAR VV 0709, Bariris, Rugby II, and Bewitched, were tested to determine germination and seedling growth. Twenty pure live seeds of each cultivar were placed in petri dishes and hydrated with 7 mL of MgSO₄ at 0.0 (deionized water), 1.6, 3.6, or 9.0 dS/m at 25/15°C with 8/16 h photoperiod cycle for 3 weeks. In another test, seeds were planted in pots to determine seedling responses to the same saline solutions. Pots were watered daily with 70 mL of the saline solutions and seedling responses (number of seedlings and tillers and tissue dry weight) and soil salinity were determined 45 days later. All KBG cultivars showed similar germination rate (average germinated seeds = 17.2) during germination regardless of MgSO₄ levels. Soil salinity increased from 0.3 to 5.6 dS/m and 0.1 to 4.2 dS/m in Study I and II, respectively, as MgSO₄ increased from 0.0 to 9.0 dS/m. Seedling growth decreased as MgSO₄ levels increased. All five KBG cultivars responded similarly to saline solutions, except in Study II where seedling numbers were the highest in ‘Rugby II’ and ‘Bariris’ (average = 11.8) and lowest in ‘BARVV0709’ (3.0) at 1.6 dS/m. Results revealed that KBG seedling growth is more sensitive to high salinity levels than germination.