On peculiarities of breeding purple-grained wheat based on varieties with anthocyanin pigmentation of coleoptiles and stems

Natural anthocyanins, which accumulate in the vegetative and generative organs of plants, performing protective functions during biotic and abiotic stress, are of interest for the production of functional foods with therapeutic and prophylactic properties. Obtaining forms of grain crops with a high content of anthocyanins is one of the rapidly developing areas in modern breeding. The formation of anthocyanins in the pericarp of common wheat grains is controlled complementarily by the Pp-1 and Pp3 genes. In contrast to the unique dominant allele Pp3 , inherited by common wheat from the endemic species Triticum aethiopicum Jakubz., dominant alleles of the Pp-1 genes are widespread among wheat varieties and, in addition to grain color, control the biosynthesis of anthocyanins in the coleoptile and stem. Consequently, the limiting factor in the accumulation of anthocyanin pigment, both in the vegetative organs and in the pericarp of the wheat grain, is the dominant allele of the Pp-D1 gene. The purpose of the study was to create purple-grain hybrids with dominant alleles of the Pp-D1 gene introduced from different varieties and to comparatively study the effect of these new alleles on the biosynthesis of anthocyanins in vegetative and generative plant tissues: in coleoptiles and in the pericarp of grains. To prove the presence of dominant alleles of the Pp-D1 gene in varieties with anthocyanin-colored coleoptiles, which are necessary for the creation of purple-grain wheat hybrids, we crossed the varieties Sibirskaya 21, Tertcia, Erythrospermum 4-16, which have this trait of coleoptile color, with almost isogenic lines C29 Pp3 P and C29 Pp3 PF, created earlier on the background of the variety Saratovskaya 29. These lines do not have anthocyanin coloring of the grains, but carry dominant alleles of the Pp3 gene. Selection was carried out using the intragenic DNA marker Pp3-diagnostic and SSR markers Xgwm0044 and Xgwm0111 linked to the Pp-D1 gene. Selected purple-grained hybrid plants with dominant alleles of target genes in a homozygous state were characterized by the presence of anthocyanin pigments in the coleoptile and in the grain, the content of which, when grown in a greenhouse, varied within the range of 35.4-69.0 and 34.1-84.2, respectively. μg/g and did not differ from the indicator in the control purple-grain lines fS29P and fS29PF, carrying both Pp genes. The correlation coefficient between the total content of anthocyanins in the grain and in the coleoptile was rs= 0.83 (p = 0.0003). New purple-grain hybrids with the highest content of anthocyanins in grains, obtained in combinations of crossing combinations Tertcia × 29 Рр3 P and Erythrospermum 4-16 × С29 Рр3 P, were tested in field conditions for yield characteristics and anthocyanin content in grains. Both lines did not differ from the Saratovskaya 29 variety in the number and weight of grains per plant and exceeded this control variety in the number of spikelets in the main ear (13.8 and 13.0 vs. 12.3), and the line based on the Tertcia variety had a statistically significantly higher weight of 1000 grains (41.6 vs.37.5). The content of anthocyanins in the grains of this line was 244.3 μg/g and practically did not differ from that of the previously obtained dark purple-grain line pBW49880P (221.4 μg/g), which inherits the dominant Pp-D1 gene from the Purple variety. The dark purple-grain lines we obtained are promising pre-varieties and donors for further selection of anthocyanin-rich varieties of bread wheat. In addition, it is possible to use a simplified scheme of monogenic inheritance of the Pp3 gene in crosses of purple-grain wheat plants with widespread wheat varieties with a colored coleoptile and stem. These varieties already containing in the genome dominant alleles of the Pp-1 genes (Pp-B1 or Pp-D1) to obtain new hybrids and varieties with a high content of anthocyanins in the pericarp of the grain. Thepolymorphic intragenic diagnostic marker of the Pp3-diagnostic gene that we have developed allows us to identify homozygous plants of the F2 generation already at early stages of development and increases accuracy.