Lotus corniculatus Classification by Seed Globulin Polypeptides and Relationship to Accession Pedigrees and Geographic Origin

Abstract

The birdsfoot trefoil (Lotus corniculatus L.) accessions from the National Plant Germplasm System (NPGS) have not been systematically evaluated to determine the genetic relationships of individuals or groups of similar accessions. This study was done to classify and determine the diversity of a collection of birdsfoot trefoil accessions using high salt‐soluble globulin polypeptides (SGPP) and to compare their classification with geographic and ecological distribution, morphology, and known accession pedigrees.. Seeds of 128 plant introductions, germplasms, and cultivars that represented a wide‐range of geographic regions and collection site ecological habitats were analyzed for SGPPs. The accessions were grouped into five major classes based on 13 protein bands ranging in molecular weights from 23.1 to 65.3 kDa. Seventy‐nine percent of the accessions were placed into two major classes with subclass differences due to collection from either highland or lowland ecoregion sites. Sixteen percent of the accessions were placed in a third class and a limited number of accessions were placed into two distinct minor classes that exhibited atypical birdsfoot trefoil morphology. Approximately 79% of the cultivars and germplasms from North and South American and Europe have been selected from a limited base of genetic resources found in the two major classes. Few improved cultivars or germplasms have been developed from materials similar to accessions found in Class 3 (18%), Class (3%), and Class 5 (0%). Using established world ecoregion descriptions greatly assisted with the interpretation of the SGPP classification and provided a useful approach that should apply to other germplasm collections.