Influence of Temperature on Leaf Growth of Diverse Populations of Tall Fescue1

Abstract

Rate and duration of leaf growth have been suggested as yield determinants in cool‐season grasses. Therefore, our objective was to compare temperature responses of leaf blade growth among diverse populations of tall rescue (Festuca arundinacea Schreb.). Seedlings of three Mediterranean populations, two European populations, and three cultivars were grown at 10, 15, 20, and 25 C with a 16‐hour photoperiod. An additional growth treatment was 8 C with an 8‐hour photoperiod.Area of leaf blade 3 (3rd complete leaf), and area and weight of leaf blade 5 were maximum, but time interval between leaves was minimum at 20 C. Elongation rate of leaf blade 3 was greatest (about 28 mm/day) at 20 and 25 C. Specific leaf weight of leaf blade 5 was highest at 10 and 15 C (3.4 mg/cm2) and decreased as temperature increased. Specific leaf weight was only 2.6 mg/cm e at 8 C, probably due to lower irradiation and shorter photoperiod than at the other temperatures.Elongation rate of leaf blade 3, as well as area expansion rate and specific leaf weight of leaf blade 5, was lowest in Mediterranean populations and highest in improved cultivars. However, time interval between leaves for Mediterranean populations was shorter than for other populations. Relative temperature response among populations was similar from 10 to 20 C. At 8 C with an 8‐hour photoperiod, population Bn 272 (from Tunisia) had higher dry weight and area of leaf blade 5 than at 10 C with a 16‐hour photoperiod. At 25 C and a 16‐hour photoperiod, area and weight of leaf blade 5 of continental populations were greater than those of Mediterranean populations. Yield superiority of improved populations may be due partially to their inherently faster leaf growth rate and larger leaves.