U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska

 

Document Type

Article

Date of this Version

November 1976

Comments

Published in 1976 Annual Meetings:

AMERICAN SOCIETY OF AGRONOMY

CROP SCIENCE SOCIETY OF AMERICA

SOIL SCIENCE SOCIETY OF AMERICA

Abstract

An in vitro assay for tall fescue leaf nitrate reductase activity (NRA) was established that required either O.5 % casein or polyvinylpyrrolidone in the extraction medium for maximal activity. Leaf NRA was proportional to light intensity and fertility levels. Mature tissue and high temperature decreased NRA. NRA showed significant genetic variability in broadly based genotypes and genotypes selected for photosynthetic rates and forage yields. However, progeny of the latter did not show significant genetic variability. High coefficients of variation (30-50%) among the heterogeneous progeny may have masked true genetic differences. No significant correlations were found between NRA and photosynthesis or yield in the parents.

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