Pentosan content genotypic variability in winter rye grain

Varieties intended for diverse use are modern priority in winter rye ( Secale cereale L.) breeding. Composition and content of pentosans are indicators to diversify rye grain use. The aim of this work was estimation of variability in total arabinoxylans and soluble arabinoxylans in rye grain. Pentosans content was determined by high performance liquid chromatography in the HPLC-RI system (JASCO Deutschland GmbH, Germany), by chemical micro method with use of orcin-chloride, and indirectly by determining the viscosity of water extract (VWE). As a result, the samples with low and high pentosan content were identified at the linear, population and hybrid level in domestic and foreign gene pools. It was shown that Russian population varieties and high-pentosan lines selected at Tatar Research Institute of Agriculture stood out due to high rates of general pentosan level and extracted viscosity. The relationship between VWE and the content of water-soluble pentosans in the studied quantitative limits with a high probability (95 %) has a rectilinear character. In low pentosans lines originated from Tatar Research Institute of Agriculture VWE amounted to 6.40-of 6.45 centistokes (sSt), in the domestic population varieties VWE ranged from 15.40 to 34.50 sSt, and in hybrid varieties from Germany VWE reached 47.50 sSt. So we have a gene pool sufficient for baking rye breeding. In high-pentosan forms, we found the high significant positive correlation between the total content of pentosans, viscosity of water extracts and water-soluble fraction. An indirect estimate of pentosans fraction through determination of the water extract viscosity of rye meal allows to start selection in the early steps of breeding and to analyze a large number of samples in a relatively short time. Further search is necessary to select donor lines with low total level of arabinoxylans and water-soluble fraction. It is difficult to phenotypically evaluate low-pentosans plants based on an indirect indicator of viscosity only. Low pentosan lines had a significant correlation between VWE and the water-soluble fraction ( r = 0.745, Р = 0.05). Heritability of water extract viscosity of grain meal was rather high (H2 = 0.71), and genotypic variation coefficient reached 32.53 %, indicating advisability of VWE improving by breeding techniques. Heritability index of water-soluble pentosan content was 0.50, and genotypic coefficient of variation was 13.02 %, so the impact of breeding on these indicators should be low. The presented genotypic variability parameters are applicable only to the genotypes used in our experiment. The smallest amounts of water-soluble pentosans in flour and meal were characteristic of the Russian varieties Marusenka, Ogonek, Chulpan 7. We revealed a low content of water-soluble fraction in the bran in variety Ogonek. To distinguish rye genotypes more precisely, it is necessary to develop effective tests which will allow to assess water absorption, viscosity and solubility of pentosans (high-molecular arabinoxylans) in addition to their quantitation in grain grind products.