Detection of fire blight resistant genes in apple trees (Malus domestica) planted in Isfahan province using SCAR and SSR markers

Plant diseases can be a limiting factor in planting in an area. One of the new methods of producing disease resistant plants is the use of molecular markers. Molecular markers are able to detect and analyze important genes of resistance. Therefore, due to the severity of fire blight, the apple tree germplasm evaluation is necessary, so this research was carried out with the aim of determining resistance genes in some apple genotypes in Isfahan province using SCAR and SSR markers.  

Fresh and young leaves of 70 samples of apple trees in Isfahan were collected in early April and DNA was extracted by CTAB method. Then polymerase chain reaction was performed and DNA fragment was detected and DNAs lengths were measured.

Results indicated that in all populations, none of the primers have a rare band or a typical band replication in 25 or less than 25% population, and 50 or less than 50% population. Semirom- Hana population had the greatest genetic diversity (Nei diversity index, Shannon, effective and different number of alleles) which shows greater genetic diversity in this population rather than other populations.Molecular analysis indicated that diversity among populations is not statistically significant and 92% of the diversity is related to diversity within the populations. The longest distance was between Semirom-Hana and Semirom-Padena populations, and in this disease, the distance between the farthest and closest populations is too low and this result was confirmed by analysis of molecular variance.

The six primers, which were used in this study, have been well produced and display the distinctions in population. Moreover, results indicate that inter-population diversity was very low but by the cross of the farthest and closest populations, then the cross of progeny can pyramidize the target genes and produce a stronger and more diverse recombination.