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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research » Research » Publications at this Location » Publication #107865

Title: HERITABILITIES OF WATER USE EFFICENCY TRAITS AND CORRELATIONS WITH AGRONOMIC TRAITS IN WATER-STRESSED ALFALFA

Author
item RAY, I.
item MUNCY, C.
item TOWNSEND, M.
item Henning, John

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: If benefits from improved water use efficiency are to be realized, heritabilities of, and correlations between important agronomic traits and key physiological traits associated with water use efficiency must be determined under water limited conditions. This study characterized genetic correlations among carbon isotope discrimination, canopy temperature, ash concentration, dry-matter yield, forage maturity, and leaf to stem ratio in alfalfa grown under water stressed field conditions. Heritabilities of the traits on a progeny mean basis were also determined. Carbon isotope discrimination, ash concentration, and yield were moderately heritable (h^2 = 0.40 - 0.56) indicating that these traits could be altered for breeding and selection. The positive correlation between carbon isotope discrimination and shoot yield suggests that germplasm should be evaluated for both carbon isotope discrimination and yield when characterizing alfalfa for high water use efficiency to minimize potential yield reductions that may result from selection based only on carbon isotope discrimination.

Technical Abstract: Alfalfa production in the southern Great Plains and western United States may benefit from improvements in water-use efficiency, the amount of forage and root biomass produced per unit of water transpired. If benefits from improved water use efficiency are to be realized, correlations between important agronomic traits and key physiological traits associated with water use efficiency must be determined under water limited conditions. This study characterized genetic correlations among carbon isotope discrimination, canopy temperature, ash concentration, dry-matter yield, forage maturity, and leaf to stem ratio in alfalfa grown under water stressed field conditions. Heritabilities of the traits on a progeny mean basis were also determined. Carbon isotope discrimination was negatively correlated with canopy temperature and ash content. An increase in dry matter yield was associated with higher carbon isotope discrimination, lower canopy temperatures, low ash concentration, taller shoots, earlier maturity, and reduced leaf to stem ratio. Carbon isotope discrimination, ash concentration, and yield were moderately heritable (h^2 = 0.40 - 0.56) indicating that these traits could be altered for breeding and selection. The positive relationship between carbon isotope discrimination and shoot yield suggests that germplasm should be evaluated for both carbon isotope discrimination and yield when characterizing alfalfa for high water use efficiency to minimize potential yield reductions that may result from selection based only on carbon isotope discrimination.