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United States Department of Agriculture

Agricultural Research Service

Title: Carbon Isotope Discrimination of Three Kentucky Bluegrass Cultivars with Contrasting Salinity Tolerance

Authors
item Qian, Y - CSU/FT. COLLINS, CO
item FOLLETT, RONALD
item Wilhelm, S - CSU/FT. COLLINS, CO
item Koski, A - CSU/FT. COLLINS, CO

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 25, 2003
Publication Date: February 15, 2004
Citation: Qian, Y.L., Follett, R.F., Wilhelm, S., Koski, A.J. 2004. Carbon isotope discrimination of three kentucky bluegrass cultivars with contrasting salinity tolerance. Agronomy Journal. 96:571-575.

Interpretive Summary: When salinity level was in the range of 2.0 to 8.0 dS m-1, (lower to higher salinity, respectively) the Kentucky Bluegrass cultivar 'Moonlight' produced 1.9-fold more root mass than did the 'NorthStar' cultivar, and NorthStar exhibited 3.9 fold more root mass than 'P105' cultivar. When salinity level increased beyond 8.0 dS m-1, NorthStar had similar root mass as Moonlight, and both showed greater root mass than P105. Cultivar P105 had a higher carbon isotope discrimination (D) than Moonlight and NorthStar without salinity stress, but a lower D than Moonlight and NorthStar at 11.0 dS m-1 salinity. The great reduction in D of P105 as salinity increased suggested that salinity induced a greater degree of stomatal resistance that provided less opportunity for discrimination against the heavier isotope. Carbon isotope discrimination may serve as a useful selection criterion in breeding effort to develop salt tolerant Kentucky Bluegrass.

Technical Abstract: We evaluated leaf carbon isotope discrimination as affected by salinity among three Kentucky bluegrass (KBG) cultivars that differ in their salt tolerance. 'Moonlight', 'NorthStar', and 'P-105' Kentucky bluegrass were grown in a solution culture and exposed to salinity levels of 2.0, 5.0, 8.0, 11.0, and 14.0 dS m-1 for 12 wks. All cultivars exhibited increased leaf firing with increasing salinity. However, Moonlight and NorthStar exhibited less leaf firing than P105 at all salinity levels. The salinity levels that caused 25% shoot growth reduction were 4.9 dS m-1 for NorthStar and Moonlight and 4.1 dS m-1 for P105, indicating that Moonlight and NorthStar have better salinity tolerance than P105. When salinity level was in the range of 2.0 to 8.0 dS m-1, Moonlight produced 1.9-fold more root mass than NorthStar, and NorthStar exhibited 3.9 fold more root mass than P105. When salinity level increased beyond 8.0 dS m-1, NorthStar had similar root mass as Moonlight, and both showed greater root mass than P105. Cultivar P105 had a higher carbon isotope discrimination (D) than Moonlight and NorthStar without salinity stress, but a lower D than Moonlight and NorthStar at 11.0 dS m-1 salinity. The great reduction in D of P105 as salinity increased suggested that salinity induced a greater degree of stomatal resistance that provided less opportunity for discrimination against the heavier isotope. Carbon isotope discrimination may serve as a useful selection criterion in breeding effort to develop salt tolerant KBG.

Last Modified: 7/28/2014
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