The use of Vrn genes for creation of triticale forms with different length of vegetation period (review)

Abstract

The advantages and disadvantages of triticale culture are briefly reviewed. The control of the length of vegetative period of spring triticale forms and spontaneous spring triticale mutants is viewed more particularly. Triticale (× Triticosecale Wittmack) is a new agricultural culture that combines valuable traits of wheat and rye. The advantages of triticale are its ability to grow on poor, acid, waterlogged soils; higher, than in wheat, content of protein in grains; its resistance to many fungus diseases. The disadvantages are undersized grains, its tendency to sprouting, lodging, a partial toxicity of grains due to the presence of alkylresorcinols, and a longer, compared to parental forms, vegetation period. The biggest influence on the length of the vegetation period of cereals have vernalization response genes - Vrn. Spring plants have one or more dominant Vrn genes, in winter plants all vrn genes are recessive. Common wheat carries genes Vrn-A1, Vrn-B1, Vrn-D1, located on the chromosomes 5AL, 5BL, 5DL respectively (A.J. Worland, 1996), Vrn-D4 gene, located on the centromeric region of chromosome 5D (N. Kippes et al., 2015) and Vrn-B3 gene on the chromosome 7BS (L. Yan et al., 2006). Rye has Vrn-R1 gene on the chromosome 5RL (J. Plaschke et al., 1993). In triticale there were detected Vrn-A1a, Vrn-B1a, Vrn-B1b and Vrn-B1c alleles (M. Nowak et al., 2014; O.I. Zaitseva et al., 2015). The same alleles were detected previously in common wheat (D.K. Santra et al., 2009; A.B. Shcherban et al., 2012, 2015; J. Milec et al., 2013; I.E. Likhenko et al., 2014). Heading time of plants can be influenced not only by an alteration of nucleotide sequence of Vrn genes, but also by a change of the copy number of these genes (A. Diaz et al., 2012). Vrn genes can influence heading time in the combination with each other. For example, cultivars with three dominant Vrn genes are ripening earlier, than cultivars with one or two dominant Vrn genes, but they have the least productivity (A.F. Stelmakh, 1993; M. Iqbal et al., 2007). It was also reported, that introgression of chromosome 2D shortened the period of triticale vegetation (A.A. Shishkina, 2008; L.V. Koren et al., 2010). Triticales have more prolonged vegetation period compared to parental wheat lines, which can be due to the inhibition of the Vrn genes by rye genome (L.N. Kaminskaya et al., 2005; I.N. Leonova et al., 2005). The genetic control of growth habit of spontaneous spring mutants is currently unknown. It was determined, that the majority of spring mutants are late ripening, and, after autumn sowing, they survive in different extent, what can mean, that they are facultative (P.I. Stepochkin, 2008; P.I. Stepochkin et al., 2008). In Siberia winter triticales occupy considerable areas, but the breeding of spring triticales hasn't been carried on yet. Spring triticales could increase biodiversity of spring cultures. Thereby creation of spring triticales with different length of vegetative period is of great breeding interest.