The objective of this article is grouping and clustering of maize inbred lines based on the results of SNP-genotyping for the verification of a separate cluster of Lancaster germplasm inbred lines. As material for the study, we used 91 maize (Zea mays L.) inbred lines, including 31 Lancaster germplasm lines and 60 inbred lines of other germplasms (23 Iodent inbreds, 15 Reid inbreds, 7 Lacon inbreds, 12 Mix inbreds and 3 exotic inbreds). The majority of the given inbred lines are included in the Dnipro breeding programme. The SNP-genotyping of these inbred lines was conducted using BDI-III panel of 384 SNP-markers developed by BioDiagnostics, Inc. (USA) on the base of Illumina VeraCode Bead Plate. The SNP-markers of this panel are biallelic and are located on all 10 maize chromosomes. Their range of conductivity equals >0.6. The SNP-analysis was made completely in automated regime on Illumina BeadStation equipment at BioDiagnostics, Inc. (USA). The grouping of the studied set of 91 inbred lines according to allelic state of SNP-markers and identifying cluster of Lancaster germplasm inbred lines in general selection of inbreeds used principal component analysis. The clustering and determining hierarchy in 31 Lancaster germplasm inbreds used quantitative cluster analysis. The share of monomorphic markers in the studied set of 91 inbred lines equaled 0.7%, and the share of dimorphic markers equaled 99.3%. Minor allele frequency (MAF) > 0.2 was observed for 80.6% of dimorphic markers, the average indicator of shift of gene diversity equaled 0.2984, PIC on average reached 0.3144. The index of gene diversity of markers varied from 0.1701 to 0.1901, pairwise genetic distances between inbred lines ranged from 0.0316–0.8000, the frequencies of major alleles of SNP-markers were within 0.5085–0.9821, and the frequencies of minor alleles were within 0.0179–0.4915. The average homozygosity of inbred lines was 98.8%. The principal component analysis of SNP-distances confirmed the isolation of the Lancaster group within the general set of analyzed inbred lines. Two-dimensional component analysis showed that the first principal component (PCA1) accounted for 36.0% of total variation and divided the investigated set of 91 inbred lines into two fractions, while all the inbred lines which are considered Lancaster based on pedigree information were included in one of the fractions. The second principal component (PCA2), which accounted for 12.1% of total variation, separated most of the Lancaster germplasm inbred lines from the others in this fraction, although the overlapping of the locations of Lancaster and non-Lancaster inbred lines was observed. Qualitative cluster analysis of 31 Lancaster germplasm inbred lines allowed us to identify two clusters: the first one includes 23 inbred lines of Ukrainian selection and the well known Mo17 (77.4% of total number of analysed lines) inbred line, and the second cluster included 6 inbred lines of Ukrainian selection and the well known Oh43 (22.6% of total number of analysed lines) inbred line. The isolation of two clusters within Lancaster germplasm indicates the genetic diversity in this plasm. The evaluation of genome similarities through allelic states of SNP-markers can successfully be used as a data source for classification and systematization of the gene pool of maize inbred lines.

Aim. This work is focused on the estimation of the callusogenic potential of 10 maize Lancaster germplasm inbreds in comparison with well-known inbreds-standards with high callusogenic ability A188, Chi31 and PLS61, and the identification of genotypes with stable morphogenic callus formation under varying conditions of donor plant cultivation during three years of researches. Methods. Method of cell, tissue and organ culture in vitro. Field method. One-way and two-way analysis of variance. Results. For the investigated Lancaster inbreds the average multi-annual value of the total frequency of callusogenesis was 80.1 %, the frequency of morphogenic type I callus formation was 25.7 %, type II callus formation was 43.8 %, but for inbreds-standards these ones reached, respectively, 96.2 %, 12.2 % and 65.4 %. The level of callusogenesis varied depending on the year of investigations for all studied genotypes. The influence of genotype, year conditions and the combination of these factors on callus induction for most of the studied inbreds was significant. Conclusions. The impact of the interaction of a genotype and ecological factors of donor plant cultivation on morphogenic callusogenesis of type I as well as type II was the most significant forLancaster inbreds.Lancaster inbreds ДK298, ДK6080, ДK212 and ДK420-1 were the most stable under varying environmental conditions on the total frequency of callusogenesis, the frequencies of morphogenic and type II callus formation. None of the studied inbreds revealed the stability on type I callus formation frequency. Keywords: maize (Zea mays L.), Lancaster germplasm, callusogenesis, culture in vitro.