CYTOPLASMIC DIVERSITY IN OLD DOMESTIC VARIETIES OF SOYBEAN USING 2 MITOCHONDRIAL MARKERS

Modern soybean [Glycine mar (L.) Merr.] cultivars are derived from a limited number of plant Introductions, which restricts germplasm diversity at both the nuclear and cytoplasmic levels, This study was conducted to use molecular techniques to assess the extent of cytoplasmic diversity available to soybean breeders, We have surveyed a collection of old domestic soybean varieties with a cloned 2.3 kilobase (kb) HindIII mitochondrial DNA fragment from the cultivar Williams 82 and the mitochondrial ATP synthase subunit 6 (atp6) gene to determine sources of cytoplasmic diversity present within this collection, This strategy revealed unique mitochondrial DNA (mtDNA) polymorphisms and polymorphism combinations, In several cases, the mtDNA polymorphisms provided a different classification than was predicted from recorded pedigrees, Variability was also detected among cultivars assigned the name Peking that were introduced independently into the USA soybean collection, The results of this survey coupled with previous studies can be used to define additional cytoplasmic groups in soybean.