QUANTIFICATION OF TANNIS IN BIRDSFOOT-TREFOIL GERMPLASM

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.