Condensed tannins in birdsfoot trefoil (Lotus corniculatus L.) have be
en detected, but not quantified extensively. The objective of this stu
dy was quantitative analysis of tannins in birdsfoot trefoil germplasm
. Diverse accessions were evaluated at two locations and on three harv
est dates, and their tissues were analyzed by near infrared reflectanc
e spectroscopy (NIRS), an accurate and efficient procedure increasingl
y used in quantitative germplasm evaluation. Ninety-seven diverse acce
ssions of L. corniculatus were obtained from the USDA Northeast Region
al Plant Introduction Station at Geneva, N.Y. Seedlings were transplan
ted to fields near Columbia and Mt. Vernon, MO. Herbage regrowth was h
arvested three times at 30-d intervals, lyophilized, and analyzed for
total condensed tannins. Treatments were arranged in a split-plot desi
gn at two locations with accessions as main plots and harvest dates as
sub-plots. Treatment combinations were replicated three times. Access
ions were clustered according to the single variable, tannin concentra
tion, by the Scott-Knott non-overlapping means separation technique. P
erformance mean and standard error of NIRS equations were 51.0 and 11.
0 g catechin equivalents (CE) kg-1 dry matter (DM), respectively; NIRS
squared correlation coefficients exceeded 0.90. Condensed tannins dif
ferent (P < 0.01) among accessions and harvest dates, and an accession
x harvest date interaction occurred P < 0.01). concentrations ranged
from 0 to 132 g CE kg-1 DM, but 75% of the accessions contained less t
han 40 g CE kg-1 DM. For accessions appearing in the highest clusters,
tannins decreased 40% at Columbia and 27% at Mt. Vernon from July to
September. Accessions from Ethiopia contained an average of 100 g CE k
g-1 DM and usually appeared in the highest clusters.