Studying Meiosis and Genetic Character of Inheritance of the Novel Type Branching in Hybrid Populations, Derived from the Crosses between a Line 171ACS and Tetra- and Hexaploid Wheat Species and Amfidiploids

A line 171ACS (AABBDD, 2n=6x=42), that derived from the cross between an Aegilotriticale or trigeneric incomplete amphidiploid [(Triticum durum Desf. × Aegilops tauschii Coss) × Secale cereale L. ssp. segetale Zhuk.] (genomic formula AABBD/R, 2n=6x=42) and a bread wheat cultivar T. aestivum L. ‘Chinese Spring’ (AABBDD, 2n=6x=42) and involved to hybridizations only with the durum (Triticum durum Desf.) and bread (T. aestivum L.) wheat cultivars up to date, have been crossed with the other tetra- (AABB, 2n=4x=28) and hexaploid (AABBDD, 2n=6x=42) wheat species, also tetra- (AADD, 2n=4x=28) and hexaploid (AADDSS, 2n=6x=42) wheat amphidiploids having D-genome. The meiosis and inheritance of the novel type spike branching in obtained these hybrid populations F1-F3 were studied. It have been found that the segregation ratios in F2 and F3 took places as 3 normal : 1 branched and 5 normal : 3 branched, respectively, i.e. a novel type of branching is inherited by a single gene to the tetraploid wheats and a line 171ACS is a source of the novel type branching not only in durum wheats, also other tetraploid wheat species. But not a single branched spike observed in hybrid populations that produced by crosses of the line 171ACS with hexaploid wheat species, also tetra- and hexaploid amphidiploids having D-genome, as well as it observed before in hybrid populations derived from the crosses among a line 171ACS and bread wheat cultivars. These results once more experimentally confirmed an inhibitor effect of D-genome chromosomes on the expression of spike branching. In spite of the both parental forms had D-genome, the branched spike forms have been generated in hybrid populations 171ACS × T. vavilovii Jakubz. and 171ACS × T. petropavlovskyi Udacz. et Migusch. This fenomen in the former explains by branchiness of T. vavilovii itself, but in the latter might be two different explanations: either in these hybrids has been activated some mechanism which prevented an inhibitor effect of D-genome chromosomes on expression branching spike, or D-genome chromosomes were eliminated in part or in full.