Genetic Diversity for Agronomic Traits and Phytochemical Compounds in Coloured Naked Barley Lines

Abstract

Interest of breeders is increasing toward the development of new barley cultivars with functional properties and adapted for food uses. A barley breeding program was initiated to develop germplasm with naked and coloured grains rich in bioactive compounds In the present study, a set of 16 F8 recombinant inbred lines (RILs) derived from the following four parental lines: 2005FG, K4-31, L94 and Priora, were evaluated in the experimental trials in Foggia (Italy) during the 2017-2019 growing seasons with the aims to assess the genetic variability for desired traits and identify superior genotypes. Lines were characterised for agronomic traits (earliness, plant height, seed yield, specific weight, 1000-seed weight) and biochemical compounds accumulation (phenolics, anthocyanins, flavonoids, carotenoids, β-glucans, proteins, antioxidant activity). A high heritability and selection response were observed for most of the biochemical compounds. The grain yield showed high significant positive genetic and phenotypic correlations (p < 0.05) with phenols and antioxidant activity. Cluster analysis grouped the genotypes into three groups. The barley RIL lines L1997, L3005, L3007 and L3009 were superior for more than four traits including seed yield and antioxidant compounds. These genotypes may serve as potential sources of nutraceuticals for healthy food and in breeding programs. In the present study, the new barley genotypes with naked and coloured grains have been selected without compromising their productivity.

Keywords: agronomic traits; breeding; coloured seed; genetic diversity; phytochemicals.

Figure 1

Hierarchical cluster analysis dendrogram (Ward’s method) and pattern map of the values of the agronomic and qualitative traits of 20 barley genotypes. Abbreviations for graph: 1, days to heading from April 1; 2, plant height (cm); 3, seed yield (t ha⁻¹); 4, specific weight (kg hL⁻¹); 5, 1000−seed weight (g); 6, total proteins (%); 7, total carotenoids (μg β carotene g⁻¹ dry matter); 8, β-glucans (%); 9, total polyphenols (μg gallic acid equivalents (GAE) g⁻¹ dry matter); 10, total proanthocyanidins (μg catechin equivalents (CE) g⁻¹ dry matter); 11, total anthocyanins (μg CE g⁻¹ dry matter); 12, total flavonoids (μg gallic acid g⁻¹ dry matter); 13, DPPH (μmol of Trolox equivalent g⁻¹ dry matter); 14, TEAC (μmol of Trolox equivalent g⁻¹ dry matter).