GENETIC VARIATION OF EUROPEAN MAIZE GENOTYPES ( ZEA MAYS L . ) DETECTED USING SSR MARKERS

The SSR molecular markers were used to assess genetic diversity in 40 old European maize genotypes. Ten SSR primers revealed a total of 65 alleles ranging from 4 (UMC1060) to 8 (UMC2002 and UMC1155) alleles per locus with a mean value of 6.50 alleles per locus. The PIC values ranged from 0.713 (UMC1060) to 0.842 (UMC2002) with an average value of 0.810 and the DI value ranged from 0.734 (UMC1060) to 0.848 (UMC2002) with an average value of 0.819. 100% of used SSR markers had PIC and DI values higher than 0.7 that means high polymorphism of chosen markers used for analysis. Probability of identity (PI) was low ranged from 0.004 (UMC1072) to 0.022 (UMC1060) with an average of 0.008. A dendrogram was constructed from a genetic distance matrix based on profiles of the 10 maize SSR loci using the unweighted pair-group method with the arithmetic average (UPGMA). According to analysis, the collection of 40 diverse accessions of maize was clustered into four clusters. The first cluster contained nine genotypes of maize, while the second cluster contained the four genotypes of maize. The third cluster contained 5 maize genotypes. Cluster 4 contained five genotypes from Hungary (22.73%), two genotypes from Poland (9.10%), seven genotypes of maize from Union of Soviet Socialist Republics (31.81%), six genotypes from Czechoslovakia (27.27%), one genotype from Slovak Republic (4.55%) and one genotype of maize is from Yugoslavia (4.55%). We could not distinguish 4 maize genotypes grouped in cluster 4, (Voroneskaja and Kocovska Skora) and 2 Hungarian maize genotypes Feheres Sarga Filleres and Mindszentpusztai Feher, which are genetically the closest.


INTRODUCTION
With the advent of the first maize hybrids, in 1933 in the US and around 1950 in Europe, maize cultivation has undergone a complete change.Numerous open-pollinated landraces adapted to specific regions were substituted by a limited number of hybrids bred from a large genetic basis (Gay, 1984).Today, the main maize hybrids cultivated in the world involve a restricted number of key inbred lines.Therefore, genetic diversity of those cultivars is almost certainly limited, in comparison to the large genetic diversity available in genebanks (Gay, 1984).A few years ago, the threat of genetic erosion led to a significant interest in the assessment of genetic diversity in germplasm collections and a huge number of studies on various crops (Dubreuil and Charcosset, 1998).
Molecular markers based on polymerase chain reaction (PCR) methods, such as simple sequence repeats (SSRs) or microsatellites, have become important genetic markers in a wide range of crop species, including maize (Elçi and Hançer, 2015).SSRs markers have many advantages over other types of molecular markers, such as co-dominance, abundant in genomes, highly polymorphisms, locus specificity, good reproducibility and random distribution throughout the genome (Sun et al., 2011).These features, coupled with their ease of detection, make them ideal for identifying and distinguishing between accessions that are genetically very similar (Saker et al, 2005).
For the analysis of genetic diversity of maize genotypes were used several dominant molecular markers: amplified fragment length polymorphism (AFLP) The present study aimed to examine the genetic variability within and among old maize genotypes cultivated in the Europe, using SSR markers.The data collected will contribute to identification, rational exploitation and conservation of germplasms of maize genotypes.

MATERIAL AND METHODOLOGY
Maize genotypes (40) were obtained from the Gene Bank VURV Praha-Ruzine (Czech Republic) and from the Gene Bank in Piesťany, the Slovak Republic (Table 1

CONCLUSION
In conclusion, a high level of genetic diversity exists among the old maize accessions analyzed.According to analysis, the collection of 40 diverse accessions of maize was clustered into four clusters.The first cluster contained nine genotypes of maize, while the second cluster contained the four genotypes (Šamorinsky konský zub, Wielkopolanka, Manalta and Toschevska) of maize.The third cluster contained 5 maize genotypes (Moldavskaja, Bučiansky Konský Zub, Milada, Bučanská žltá and Iregszemeseil 2 hetes).Cluster 4 contained 22 genotypes of maize.We could not distinguish 4 maize genotypes grouped in cluster 4, (Voroneskaja and Kocovska Skora) and 2 Hungarian maize genotypes -Feheres Sarga Filleres and Mindszentpusztai Feher, which are genetically the closest.A SSR marker system is a rapid and reliable method for cultivar identification that might also be used in quality control in certified seed production programs, to identify sources of seed contamination, and to maintain pure germplasm collections.
Filleres and Mindszentpusztai Feher, which are genetically the closest.Similar results were detected by other authors (Krishna et al., 2012; Kanagarasu et al., 2013; Molin et al., 2013; Qu and Liu, 2013; Al-Badeiry et al., 2014; Shiri, et al., 2014; Efendi et al., 2015; Ignjatovic-Micic et al., 2015; Salami et al., 2016) and these results presented a high level of polymorphism of old maize genotypes detected by SSR markers.In the present investigation (Krishna et al., 2012), 48 microsatellite markers were used for analyzing genetic diversity among the sixty three quality protein maize lines.Polymorphic profiles for 37 simple sequence repeat (SSR) loci aided in differentiating the QPM inbred lines.Using SSR procedures, the number of alleles per locus ranged from two to six, giving a total of 151 alleles for the 37 SSR loci.

Figure 2
Figure 2 Dendrogram of 40 maize genotypes prepared based on SSR markers.

Table 1
List of 40 analyzed genotypes of maize.

Table 2
List of SSR primers of maize (

Table 3
List of SSR primers, total number of bands and the statistical characteristics of the SSR markers used in maize.

Al- Badeiry et al. (2014) detected
selected SSRs with unique flanking sequences and then applied to analyze the polymorphism of nextgeneration sequencing data from 345 maize inbred.There were 58,946 SSRs with length information results in ten or more than ten genomes, accounting for 71.28% of SSRs with unique flanking sequences, while 55,621 SSRs had polymorphism, with an average PIC value of 0.498.41 alleles among the tested maize varieties using 10 Simple Sequence Repeat (SSR).The molecular size of bands obtained from amplification of SSR products ranged from 91 to 288 bp.