Diversity of leaf pubescence in bread wheat and relative species

Interspecific hybridization and polyploidization are the characteristic processes of evolution in the world of plants. The allopolyploid genomes undergo numerous structural rearrangements associated with the adaptation of separate genomes to each other. An important issue is to establish which part of the total diversity of genes characteristic of the ancestral forms have been preserved and manifested in the complex genomes. The aim of this work was to compare the diversity of the adaptive morphological trait-leaf pubescence among the relatives and the ancestors of hexaploid wheats to establish the variability of its phenotypic manifestation as a result of evolution and domestication. This was achieved through the study of quantitative characteristics of leaf pubescence among 47 representatives of di-, tetra- and hexaploid species of genera Triticum and Aegilops, the donors of the individual genomes of the allopolyploid Triticum species. Quantification of leaf pubescence was based on automated counting of the trichome number (N) and trichome length (L) estimation on a leaf fold and calculation of the pubescence index H (L/N). The species with different sets of elementary genomes differed for the type of pubescence. The ploidy level affected only the trichome length and the index of pubescence H (L/N) . The density of the hairs was affected by the individual genomes A and B, whereas genome D significantly influenced all of the studied pubescence parameters. The diploid species showed the largest variability while the cultivated durum wheats lacked pubescence. Bread wheat demonstrated pubescence characterized by a close correlation between N and L.