Cytogenetic and molecular identification of novel wheat- addition lines with resistance to leaf rust and the presence of leaf pubescence trait.

Introduction: Emerging new races of leaf rust ( Eriks) are threatening global wheat ( L.) production. Identifying additional resistance genes from all available gene pools is crucial to expanding wheat resistance to these virulent leaf rust races.

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The degree of dominance and the coefficient of heritability have been investigated as indicators of the allelic interaction at loci Rht8 and Rht-B1, which is characterized by the partial, complete or over dominance of greater plant height and by the low or medium heritability. Alleles with a weaker or without direct negative effect dominate under alleles reducing the plant height stronger. The impact of weather conditions on a change of the dominance is discussed.

[PLEIOTROPIC EFFECTS OF GIBBERELLIN-SENSITIVE AND GIBBERELLIN-INSENSITIVE DWARFING GENES IN COMMON WHEAT OF THE SOUTHERN STEP REGION OF BLACK SEA].

Investigations of the pleiotropic effects of GA-sensitive (Rht8) and GA-insensitive (Rht-B1, Rht-D1) dwarfing genes and a gene that determines the response of plants to photoperiod--Ppd-D1 were carried out for three years in the southern step region of Black Sea bank on five different genetic backgrounds. It is shown that in addition to direct effects on plant height GA-sensitive and GA-insensitive dwarfing genes have pleiotropic effects on all studied traits except the number of fertile spikelets. Presence of the dwarfing genes in the genotype of tall forms led to the decrease of stem and ear length, and at the same time to the increase of ear density.

[Effects of dwarfing genes on the genetic background of wheat varieties of the south Ukraine region].

Effects of the Rht8c, Rht-B1b, Rht-B1e and Rht-D1b genes on the plant height of wheat have been investigated. Variations of these effects are significantly modified by genetic background and year conditions. Complex of the alleles Rht8c Rht-B1a Rht-D1b Ppd-D1a is advantageous for the conditions of the South Ukraine region.

[Gibberellin signaling pathways in plants].

During the last decade plant growth and development have been investigated at the molecular level. Plant specific family GRAS-proteins plays one of the key roles in the molecular mechanisms of this process. In this report we highlight the importance of DELLA-proteins and show the model ofgibberellin signalling pathway in plants that starts from the binding of biologically active gibberellic acid with receptor and DELLA-protein.