New approaches in winter rye breeding for grain quality

Abstract

Introduction. Winter rye grain is traditionally used for the production of bread, alcohol, starch, malt, but very seldom for fodder. For this reason, every year a significant part of harvested rye remains unclaimed, it does not stimulate the growth of its production.This is due to the fact that, in comparison with other cereals, rye contains relatively high contents of non-starch polysaccharides (pentosans), which are undesirable in fodder. The total pentosans in rye grain vary slightly across varieties (9.2-11.5%), but their expression is significantly affected by environmental factors. The major structural component of non-starch polysaccharides is five-carbon sugars - arabinose and xylose (so-called arabinoxylans – AX), which are capable of producing highly viscous aqueous solutions at relatively low concentrations.The aim and tasks of the study. The purpose of this work - to evaluate the effectiveness of 9-time divergent selection based on the trait of ‘aqueous extract viscosity’ (AEV), to explore varietal specificity in response to selection, to study the degree of breeding shift asymmetry and to determine its correlative impact on technological and baking qualities of grain.Materials and methods. The starting material for AEV selection was winter rye varieties -populations ‘Alfa’ and ‘Moskovskaya12’.Results and discussion. The potential of aqueous extract viscosity is directly dependent on water-soluble AX content in rye grain (r = 0.97), in connection with which it can serve as an indirect index of their amount. It was found that aqueous extract viscosity is in negative (r = -0.82) correlation with protein digestibility in rats, and xylanase and arabinosidase as supplements to the diet, promoting AX depolymerization, eliminate the harmful effect of rye ingredient in fodder, and the less rye grain the diet contains, the greater the effect of enzymes is.Therefore, to improve the nutritional value of rye grain, targeted breeding for low AX content is necessary in order to provide low viscosity rye fodder in animals’ stomachs. It is believed that such rye varieties will compete with triticale. Some researchers believe that molecular structures of water-soluble AX play a more important role than their amounts.After 9 selection cycles, the AEV in divergent populations from variety ‘Alfa’ differed by 7.2 times, and in populations from variety ‘Moskovskaya12’– by 12.3 times. The cause for such an ambivalent response of varieties to selection could lie in background differences in levels of phenotypic dispersion of the trait selected in the original varieties.Conclusions. Intrapopulation selection of genotypes contrasting in viscosity led to a strong divergence of populations in terms grain quality traits due to correlative reactions. In this regard, multiple divergent selections based on AEV can be recommended as an efficient method of rye breeding for targeted use.