ISSN 10227954, Russian Journal of Genetics, 2010, Vol. 46, No. 7, pp. 819–827. © Pleiades Publishing, Inc., 2010.
Original Russian Text © M. Smolik, O. Krzysztoszek, 2010, published in Genetika, 2010, Vol. 46, No. 7, pp. 923–931.
Apple trees are among the most important com
mercial fruit trees grown in moderate climate zones. A
large number of cultivars available on the market are
the result of free pollination of breeding trees, con
trolled hybridization and somatic mutation. Numer
ous apple tree cultivars are allogamous forms, often of
an unknown origin. In practice, they are obtained by
vegetative propagation. Their monoclonic character
and the fact that a large number of apple tree cultivars
were formed by mutation indicate that inter and
intracultivar genetic variability is reduced to a mini
mum within their range .
Thus, a thorough genetic characterization of the
aforementioned apple tree forms is important for at
least two reasons; they are very useful for breeding pro
grams, as well as for copyright protection of the newly
obtained cultivars .
Traditional methods of characterising and estimat
ing the genetic diversity of plants are based on the
analysis of morphological, phenological and agro
nomical features. It is well known, however, that these
parameters are significantly modified by environmen
tal conditions. For many years, a precise description of
this variability has been carried out using modern
molecular biology to elucidate the differences under
ling this genetic diversity .
The article is published in the original.
The ISSRPCR method is an analytical technique,
by which one can precisely characterise genetic vari
ability at the level of DNA. It is based on the analysis
of variability within the range of highly polymorphic
microsatellite sequences .
According to , microsatellite sequences contain
a higher number of random mutations then other
regions of the genome. The most likely reason for
these mutations is due to the inherent error rate of
DNA polymerases. This may be, among other things,
the result of incorrect copying of the chromosomes by
DNA polymerase (slippage of DNA polymerase),
which could take place in the interphase prior to each
division of the cell . According to the literature, the
height mutation rate of microsatellite sequences even
tually results in a series of insertions or deletions
resulting in changes within the repeated block of
sequences or in the number of its repeats.
The studies showed that the microsatellite
sequences occur in introns, exons, centromeric and
telomeric regions of chromosomes . Thus, we
believe that our choice of research methods for the
molecular characterization of the two groups of apple
trees are justifiable. These methods allow for the char
acterization of a full spectrum of transcribable DNA
variability (polymorphism of ISSR amplicons) at the
level of genes or the sequences in their vicinity. These
Evaluation of Genetic Variability in Choosen Apple
by ISSRPCR Analysis
M. Smolik and O. Krzysztoszek
Department of Horticultural Plant Breeding, West Pomeranian University of Technology, Szczecin, 71424 Poland;
Received April 07, 2009; in final form, January 12, 2010
—The aim of the study was to determine the genetic variability in eight apple cultivars: Delikates,
Cortland, James Grieve, Lired, Jonathan, Golden Delicious, Jonagold, and Idared from the collection of
Fruit Growing Research Station in Rajkowo of the West Pomeranian University of Technology, Szczecin. The
cultivar Delikates was obtained from the crossing of two cultivars: Cortland, and James Grieve, whereas cul
tivar Lired is a James Grieve’s sport. The second one cultivar—Jonagold was obtained from the crossing of
Jonathan and Golden Delicious. The cultivar Idared is a hybrid obtained from the crossing of Jonathan and
Wagener. Out of 40 primers, 17 were chosen for the final study. Those amplified a total of 183 loci (872 ampl
icons) out of which 34 (18.5%) were monomorphic, 128 (69.5%) were polymorphic and 22 (12%) cultivar
specific. Specific ISSR products were detected for each apple cultivar. A dendrogram was constructed using
the UPGMA method which revealed two distinct clusters: I—Delikates, Cortland, James Grieve and Lired,
II—Jonathan, Golden Delicious, Jonagold and Idared. Genetic similarity between Delikates, Cortland and
James Grieve was 68.6, 70.8%, respectively and between cultivar Jonagold, Jonathan and Golden Delicous
was 79.8, 85.2%, respectively.