Background: Calibrachoa
Cerv. (ex La Llave & Lexarza) is a genus of the Solanaceae family (La
Llave and Lexarza, 1825). This genus has a high ornamental and economic value due to its intrinsic
variability and multiplicity of flower colours. In Argentina there are eight native species, and one of them
is
Calibrachoa caesia. The genetic diversity among 35 accessions of
C. caesia, from five departments
in the province of Misiones, was analyzed using ISSR markers.
Results: Thirteen ISSR primers
yielded a reproducible banding pattern, with 701 amplified loci and 98% of polymorphism. The ISSR
primers 5’CT, 5’CA, 5’GA, 5’GACA, 3’CAC, 3’TG and 3’TC generated 100% polymorphic patterns. The
Rp values ranged from 23.20 to 10.29 for 5’GACA and 3’AG primers, respectively, while the average
values for MI and PIC were 0.367 and 0.231, respectively. The more informative primers were 5’GACA
and 5’GA, and the less informative was 3’AC. Simple matching coefficient of similarity varied from
0.8875 to 0.6659, indicating high levels of genetic similarity among the genotypes studied. The
UPGMA cluster analysis indicated three distinct clusters; one comprised genotypes of the five
departments, while the second included individuals from Guaraní and Oberá regions and the third
cluster included the San Pedro individuals. The overall grouping pattern is in agreement with principal
coordinate analysis (PCoA).
Conclusions: The Bayesian cluster analysis revealed structuring of the C.
caesia population and two clusters were identified, which correspond to UPGMA major clades. The
AMOVA test for all populations showed highest genetic variation within populations (90%), meanwhile
the F
st coefficient was 0.098, indicating a medium differentiation between populations. These results
showed a great intrapopulation genetic diversity but no significant difference was detected among
populations. In this work the use of thirteen ISSR markers, allowed the characterization of every
individual examined. Therefore, the possibility of using molecular data for varietal identification is a
promising tool for application in future breeding programs in the genus
Calibrachoa.
