LEAF WATER POTENTIAL AND RELATIVE WATER-CONTENT VARIATION IN CREEPINGBENTGRASS CLONES

Creeping bentgrass (Agrostis palustris Buds.) often requires daily irr igation and syringing to persist in turf areas in warmer environ ments with high evapotranspiration rates. Turfgrass performance could be en hanced if turgor maintenance under decreasing soil moisture levels cou ld be incorporated into new bentgrass cultivars. The objectives of thi s study were to determine: (i) if genetic variation in leaf water pote ntial (LWP) existed among creeping bentgrass clones under declining so il moisture, (ii) if LWP was associated with maintenance of growth und er declining soil moisture levels, and (iii) if genotypic variation ex isted in water-relation characteristics, including components of LWP, as determined by a hydraulic press. The LWP was measured on four field -grown creeping bentgrass clones twice per day with a hydraulic press. Leaf water potential and soil moisture levels were determined in a gr owth room study on five creeping bentgrass clones grown in pots, 17 by 13 cm, during a 17-d period. Water-relation characteristics were dete rmined on five creeping bentgrass clones grown in a greenhouse using a hydraulic press. Genetic variation existed among clones in LWP in bot h field and growth-room studies. The most negative LWP was not associa ted with the greatest leaf firing or decrease in leaf extension. The r elative water content at zero turgor represented a substantial differe nce in the degree of hydration at zero turgor. This study illustrated that genetic variation exists for LWP and relative water content in cr eeping bentgrass.