Dj. Crawford et al., GENETIC-VARIATION IN RUNNING BUFFALO CLOVER (TRIFOLIUM-STOLONIFERUM -FABACEAE) USING RANDOM AMPLIFIED POLYMORPHIC DNA MARKERS (RAPDS), Annals of the Missouri Botanical Garden, 85(1), 1998, pp. 81-89
Trifolium stoloniferum Muhl. es Eaten (Fabaceae), a perennial, stoloni
ferous herb commonly known as running buffalo clover, once occurred ov
er a large area in the Midwest (U.S.A.) but is currently restricted to
five states and is federally endangered. The purpose of this study wa
s to examine genetic variation within and among populations of T. stol
oniferum throughout its known geographic distribution using Random Amp
lified Polymorphic DNAs (RAPDs) as markers. The average within-populat
ion banding similarity values for 390 individuals from 21 populations
are high, ranging from 0.920 to 0.984 (mean = 0.952). The mean banding
similarities for comparisons between populations range from 0.856 to
0.902 (mean = 0.884), implying that much of the diversity resides amon
g populations in this species. There are also differences in average s
imilarities within and between patches at the population level, sugges
ting substructuring within populations. A large proportion of plants s
ampled within populations have different banding patterns, indicating
that populations do not consist of one to several genets perpetuated v
egetatively by stolons. Our results agree with those of previous worke
rs using allozymes in showing relatively low levels of diversity withi
n populations and in the species as a whole. However, in the present s
tudy RAPD-marker variation was detected in all populations, with level
s of diversity in several smaller populations equal to those in larger
ones; no allozyme variation was detected in half of the populations s
ampled, and smaller populations were often monomorphic. Two bands are
unique to Missouri populations and one band was found only in Ohio pop
ulations. Allozyme data were used to suggest that conserving smaller p
opulations could be of lower priority because they lack diversity; cer
tain ones are identical to each other, and thus they may consist of si
ngle genets. By contrast, RAPDs show that even the smallest population
s have a high proportion of different genets and thus are worthy of fu
rther consideration for conservation.