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TALL FESCUE SOIL MOISTURE DEPLETION, EVAPOTRANSPIRATION AND GROWTH PARAMETERS
Growth chamber and field experiments were conducted with tall fescue (Festuca arundinacea Schreb.) to: (1) investigate the genetic response of tall fescue germplasm sources for root and shoot growth parameters under mowing stress (2) test the growth performance and associative soil moisture extraction of replicated clonal material based on divergent, directional and random seedling selections and (3) evaluate evapotranspiration (ET) and consumptive water use on a intraspecific basis. In the growth chamber, unmowed seed sources had significantly different mean leaf area and root number, while mowed sources were significant for mean leaf number and deepest root. Sources differed in root growth parameters which may relate to drought avoidance. Broadsense heritability and coefficients of genetic variation for growth parameters of mowed seedling sources based on a plants/plots analysis ranged from 1.2 and 34.1, and 1.5 to 17 respectively.^ Field shoot and root production were highly significant on a clonal basis and were under moderate to high genetic control. Soil moisture extraction was significant for clones, but changed with depth and time. Seedlings selected for high root production tended to have high field root production. Total field root production and soil water present in the 120 cm profile at the end of a 75 day induced drought were related (r = 0.78) and significant at the 0.01 probability level. Visible wilt response for two thirds of the clones tested could be explained in terms of soil moisture, indicating drought avoidance.^ Cultivars differed in ET rates determined on ground and leaf area basis, using mini-lysimetry. Calculated and theoretical leaf area index (LAI) values were correlated (r = 0.89, p (GREATERTHEQ) 0.01), verifying effective use of a nondestructive technique for turf LA estimation. Cultivars with low LAI had high ET rates on both the leaf and ground area basis. Cultivars differed for individual crop ratios, fraction of available water used, and wilt expression. ^
DAVID M KOPEC,
"TALL FESCUE SOIL MOISTURE DEPLETION, EVAPOTRANSPIRATION AND GROWTH PARAMETERS"
(January 1, 1985).
ETD collection for University of Nebraska - Lincoln.