Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 7, 2002
Publication Date: October 31, 2002
Citation: STEINER, J.J. BIRDSFOOT TREFOIL FLOWERING RESPONSE TO PHOTOPERIOD LENGTH. CROP SCIENCE. 2002. v. 42. p. 1709-1718. Interpretive Summary: Birdsfoot trefoil (BFT) is an excellent non-bloating legume that increases the nutritive value of grazed pastures. However, BFT is susceptible to root and crown rot that reduces its persistence. To increase BFT natural reseeding, varieties are needed that will flower under relatively short day lengths found in the southern U.S. pasture belt. This research developed a method to evaluate BFT genetic lines for flowering and evaluated 68 accessions from the USDA National Plant Germplasm System collection. Plants collected from northern latitudes flowered less at photoperiod lengths similar to those at lower latitudes than materials collected from more southern latitudes. To increase flowering under lower latitude conditions, plant breeders should select plants that will flower profusely at these conditions. To increase natural reseeding in southern pastures, genetic materials were identified in the U.S. collection that could be used to develop new varieties.
Technical Abstract: Birdsfoot trefoil (Lotus corniculatus L.) is an Old World perennial forage legume that is widely adapted to environments ranging from Scandinavia in the north to highlands near the equator in the south. Because of poor root and crown rot resistance, birdsfoot trefoil requires reseeding to persist in pastures. The purpose of this research was to determine the effects of photoperiod length and collecting site ecogeography on birdsfoot trefoil flowering. The flowering response index (FRI) was used to describe 68 accessions grown in 10, 13, 16, and 19 h photoperiod lengths. As photoperiod length increased, the percentage of clones in an accession that flowered increased. Photoperiod lengths 16 h were too long to differentiate germplasm, and thus should not be used as a selection criterion for flowering at low latitudes. Under 13 h photoperiod length conditions and as collecting site latitude increased, the FRI and percentage of clones in an accession that flowered decreased. When selecting genotypes for use in low latitude pastures, the flowering response at 13 h photoperiod should be considered if reseeding is desired.