|Garcia D L Santos, G - MEXICO|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2000
Publication Date: April 30, 2001
Interpretive Summary: Birdsfoot trefoil is an important forage legume for livestock production and has other uses as a conservation species where habitats have been disturbed. The USDA National Plant Germplasm System collections contain a wide array of genes of this and other species that can be used to developed improved varieties. To make these genes more easily available and useful to forage breeders and conservationist interested in restoring habitats, methods are needed to identify the plant germplasm that may be best adapted for use in different regions of the world. This research showed that plant crossing ability was associated with ecogeographic features of the collecting site, but not with morphologic characteristics. This differs from other findings that morphology was correlated with ecogeographic origins and genetic similarities based on RAPD markers. Exotic birdsfoot trefoil genotypes can be utilized with commercial quality germplasm using conventional crossing methods.
Technical Abstract: Birdsfoot trefoil (Lotus corniculatus L.) is a widely distributed Old world perennial forage legume found in wild and naturalized populations throughout temperate regions of the world. Exotic birdsfoot trefoil germplasm has rarely been used for birdsfoot trefoil genetic enhancement and information about its crossing ability with commercial quality germplasm is not available. The objectives of this research were to characterize the crossing ability of 27 exotic birdsfoot trefoil genotypes with two genetically diverse hybridization testers, and determine if crossing ability among genotypes was related to their genetic background and ecogeographic origins. Crossing ability was determined using reciprocal crosses with one commercial quality germplasm and one exotic genotype tester. All possible crossing combinations for an eight-genotype subset were also determined. Crossing ability was measured as percentage of flowers pollinated that set pods, F1 progeny pollen viability, pod length, and seeds per pod. Self-genotype pod set and pollen viability were not correlated. Intermediate bridge crosses were identified that could potentially overcome specific cross incompatibilities and be used to obtain progeny for any combination of genotypes. Genotype crossing ability was associated with ecogeographic features of the collecting site, but not with morphologic characteristics. This differs from findings that other genotype morphologic characteristics are associated with ecogeographic origins and genetic similarities based on RAPD markers. Exotic birdsfoot trefoil genotypes can be utilized with commercial quality germplasm using conventional crossing methods.