Derkach K. The biotechnological characteristic of maize Lancaster germplasm genotypes.

The biotechnological characteristic of maize Lancaster germplasm genotypes according to the results of molecular genetic, cell engineering and genetic engineering studies is introduced in the thesis. A comparative analysis of the results of SNP genotyping of representatives of maize Lancaster germplasm inbreds and other types of maize germplasm was performed. Allelic variants of SNP-markers specific for Lancaster germplasm inbreds were identified. A specific set of Lancaster germplasm alleles was determined by the frequencies of the major alleles of the ten top-SNP markers in comparison with inbreds of other germplasms. The genetic diversity of the maize inbreds within Lancaster germplasm was estimated. The presence of two subclusters within Lancaster germplasm was confirmed by the cluster analysis. One, the Mo17 inbred, was a typical representative of the Mo17 subplasm, and the other, the Oh43 inbred, was a typical representative of the Oh43 subplasm. Relationship of modern Lancaster inbreds with typical representatives of this germplasm, based on SNP-genotyping, ranged in 52.2-89.7% for Mo17 and 48.2-66.8% for Oh43. Cell engineering investigations showed that Lancaster genotypes had specific qualitative and quantitative characteristics of the callusogenesis and regeneration potential, which differentiated them from the representatives of other maize germplasms, that should be taken in cell engineering studies. There were significant variations in the callusogenic ability inside the Lancaster germplasm. The average levels of the common frequency of callusogenesis, the frequency of morphogenic callus formation, in particular type I and type II, increased proportionally in the studied subplasms and groups in the direction of Mo17→Mo17mix→Oh43→Mo17/Oh43, along with the saturation of unrelated genetic material. Lancaster germplasm inbreds, stable over the years, were productive for the formation of calli of type II but unstable for the formation of calli of type I. The regeneration potential of Lancaster germplasm inbreds was low, but increased in hybrids with inbreds of high cultural response A188, Chi31 and PLS61. It is noted that the modification of the media for induction of callusogenesis and regeneration leaded to variability of callusogenesis and regeneration parameters depending on genotype. Genetic engineering investigations showed the existence of potential of the possibility of involving of Lancaster genotypes to genetic transformation. The biolistic transformation of callus tissues of such genotypes by vector pAHC25 with foreign genes uidA and bar was carried out. It was noted that phosphinothricin as a selective agent of the media for callusogenesis and regeneration had a prolonged 24 influence, and its effect significantly inhibited the vital activity of maize callus tissue not on the stage of callusogenesis, but during the period of plant regeneration. The positive effect of genetic transformation with gene bar on resistance to phosphinothricin is first demonstrated at the stage of plant regeneration. The expression of bar gene was also confirmed by the treatment of plants in the phase of seedlings with a herbicide «Basta»TM. In later generations of self-pollination the survival of plants after treatment with a herbicide reached up to 100%. Eight new transgenic maize inbreds within Lancaster germplasm resistant to active ingredient of «Basta»TM herbicide, phosphinothricin, were obtained.