Grain Quality and Stability of Advanced Barley Lines and Local Landraces in Mediterranean Conditions

Key findings from this study

• The study found that classical pedigree-derived barley lines demonstrated the highest stability across most grain quality traits when evaluated across six Mediterranean environments.
• The researchers demonstrate that broad-sense heritability exceeded 92% for all evaluated traits, with particularly strong genetic control of protein, fat, ash, and crude fiber content.
• The authors report that crude protein and carbohydrate content show significant negative correlation, while fat content positively associates with ash and fiber-related components, indicating both trade-offs and coordinated accumulation patterns relevant to breeding strategy.

Overview

This study evaluated grain quality traits across 15 barley genotypes, encompassing advanced breeding lines and local germplasm, cultivated across six Mediterranean environments. The research quantified the relative contributions of genetic and environmental factors to trait variation and assessed genotype stability across locations. Classical pedigree-derived lines demonstrated the highest stability, while selection-derived lines showed intermediate performance. High broad-sense heritability (>92%) characterized all measured traits, indicating strong genetic control.

Methods and approach

Fifteen barley genotypes representing distinct breeding strategies underwent field evaluation across six environments using a randomized complete block design with four replications per environment. Measured parameters included crude protein, fat, ash, starch, crude fiber, carbohydrate, soluble fraction, and non-starch fraction content. Combined ANOVA partitioned variance into genotype, environment, and genotype × environment interaction components. Stability analysis employed the Stability Index to rank genotypes. Heritability calculations used broad-sense estimates, while genetic advance metrics quantified expected selection response.

Results

Classical pedigree lines (G1–G5) exhibited the highest stability across most traits, followed by Plant Yield Index and Yielding Coefficient-selected lines. The local population showed lower stability, while cultivars demonstrated intermediate, trait-dependent patterns. Broad-sense heritability exceeded 92% for all traits, with protein, fat, ash, and fiber content showing particularly strong genetic control. Starch, carbohydrate, soluble fraction, and non-starch fraction were more environmentally sensitive. Crude protein negatively correlated with carbohydrate content, soluble fraction, and non-starch fraction. Fat content positively associated with ash content and fiber components, revealing potential breeding targets.

Implications

High heritability across all quality traits indicates that selection pressure can effectively improve grain composition in Mediterranean barley production. The superior stability of classical pedigree lines suggests that conventional breeding approaches retain robustness across variable field conditions, supporting their continued use in breeding programs. Trait-specific environmental sensitivity requires multi-environment testing protocols to reliably estimate breeding values, particularly for traits showing greater environmental influence such as starch and carbohydrate accumulation.
Negative associations between protein and carbohydrate fractions present breeding constraints, as simultaneous improvement of both traits may prove difficult. Conversely, coordinated positive relationships among fat, ash, and fiber components suggest opportunities for developing improved barley lines through selection on correlated traits. Advanced lines combining high performance with environmental stability provide material suitable for further development under Mediterranean agroecological conditions.

Scope and limitations

This summary is based on the study abstract and available metadata. It does not include a full analysis of the complete paper, supplementary materials, or underlying datasets unless explicitly stated. Findings should be interpreted in the context of the original publication.