Height inheritance in durum wheat (Triticum durum Desf.) hybrids with D<sub> 2</sub> and D<sub> 3</sub> hybrid dwarfing genes

Abstract

Background. Durum wheat (BBAuAu, 2n=28) carries the D2 and D3 hybrid dwarfing genes. A study of the nature of D genes and a research of their influence on the adaptive and selectively valuable traits of hybrid plants with hybrid dwarfing genes is of theoretical and practical interest. It was previously established that the dominant alleles of the D2 and D3 genes significantly reduce the height of durum wheat hybrid plants and positively affect the kernel size and vitreousness. The purpose of the present work was to study the inheritance of height in hybrids obtained by crossing a semi-dwarf durum winter wheat cultivar with lines carrying hybrid dwarfing genes. Material and methods. The material of the study was four lines of durum wheat: L-961, L-962, L-963 and L-964 carrying hybrid dwarfing genes D2 and D3, a cultivar of semi-dwarf winter durum wheat ‘Krupinka’ (k-64725) with the rht1 gene, and hybrids of these lines with this cultivar. ‘Krupinka’ was used as the female parent in hybridization by controlled pollination. The degree of dominance was determined according to Beil and Atkins. Statistics were performed using the Pearson’s -x2 test. Results and conclusions. The analysis of plant lines of durum wheat with the D2 and D3 hybrid dwarfing genes showed that the average height of the ‘Krupinka’ × L-962 and ‘Krupinka’ × L-963 hybrids was 30 cm lower compared to the tall parent, the degree of dominance was 0.9 and 1.9 respectively. In hybrids with lines L-961 and L-964, there was no dominance of short stature. The height variability in F2 hybrids was continuous and prevented combining them into any phenotypic classes. The F3 families of ‘Krupinka’ × L-962 and ‘Krupinka’ × L 963 hybrids segregated by height into three phenotypic classes. The actual ratio of phenotypic classes did not contradict the theoretical one of 10:3:3. The obtained numerical ratios of F3 families are generally similar to those found in the literature. A distinctive feature is the absence of recessive alleles in D genes. It is assumed that the latter are regulators of phytohormone gene depression and do not have recessive alleles. It will be more correct to designate the observed phenotypic classes as D2D2 i and D3D3 i, where D2 i и D3 i denote homologues of chromosomes with a different number of multigenes. Conclusion. The study of height inheritance in the obtained hybrids indicated the presence of dominant D2 and D3 genes in the L-962 and L-963 lines and of the semi-dominant D3 gene in the L-961 line. A distinctive feature of height inheritance in durum wheat lines with the D2 and D3 hybrid dwarfing genes is the absence of recessive alleles in the D genes, i.e. no dominance of short stature