Morphological and Growth Characteristic of Low- and High-Water Use Kentucky Bluegrass Cultivars
- J. S. Ebdon and
- A. M. Petrovic
As the competition for water increases, there is a need to conserve limited water resources applied to irrigated turfgrass sites. Consistent with this effort is the identification of water conserving Kentucky bluegrass (Poa pratensis L.) because low consumptive water use may be important in reducing irrigation requirements by enhancing drought resistance. Low evapotranspiration (ET) rates under non-limiting soil moisture conditions have been associated with turfgrass morphology and growth characteristics that increase canopy resistance to ET and reduce leaf area components. Much of this previous research emphasized warm-season turfgrass. A greenhouse study was conducted to determine the relationship between morphological and growth characteristics in 61 Kentucky bluegrass (KBG) cultivars and comparative water use. By means of cluster analysis, the 61 KBG cultivars were categorized as either low- or high-water use cultivars based on ET rates evaluated in the growth chamber across three evaporative demand environments (1.263, 1.664, and 2.261 kPa VPD). Morphological and growth characteristics were assessed from unmowed, spaced plants and mowed turfgrass grown in fritted clay filled lysimeters. Based on single plant morphology, low-water use cultivars had 13% more horizontal leaf orientation, 6% narrower leaf texture, 13% more lateral shoots per plant, 12% slower vertical leaf extension rate, 2% more leaves per shoot, and 7% shorter leaf blades and sheaths than the high-water use cultivars. Based on turfgrass morphology from mowed lysimeters, the low-water use cultivars had 17% more horizontal leaf orientation, 10% narrower leaf texture, 15% more shoots, 4% slower vertical leaf extension rate, and 4% shorter leaf sheaths than the high-water use group. Canopy resistance to ET was not measured in this study; however, leaf angle (assumed component of canopy resistance) was the only plant characteristics evaluated under mowed conditions whose correlation with turfgrass ET exceeded 0.50 in absolute value. Differences observed among water use groups based on single plant- and turfgrass-morphology was not always consistent with the high canopy resistance to ET/low leaf area hypothesis. However, characteristics were identified which may be useful in selecting for KBG with a low-water use pattern.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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