Salt Stress Effects on Forage Production and Turf Characteristics in Smooth Bromegrass (Bromus inermis L.): Genetic Variability and Breeding Opportunities

Salinity and water scarcity in arid and semi-arid regions pose significant challenges for turf-grass production and quality. The utilisation of salinity-tolerant turf grass genotypes is essential for enhancing their cultivation in both pasturelands and urban landscapes. Understanding the genetic variation of agro-morphological and turf quality characteristics, their associations, and the potential for simultaneous selection across forage and turf traits under salt stress conditions has not yet been thoroughly investigated in smooth bromegrass. In this study, 74 genotypes of smooth bromegrass (Bromus inermis L.) were assessed for forage, different agro-morphological, turf quality characteristics, and salt tolerance at five cuts in the field across 2 years of 2022 and 2023 under normal and salt stress conditions. Considerable genetic variation and estimate of heritability (h²_b) were observed for measured traits under both conditions in the studied panel. The range of h²_b was from 0.45 to 0.92 under normal and from 0.36 to 0.83 under salt stress conditions. Salt stress had an adverse effect on the forage yield (DFY), yield components and turf quality characteristics. On average, salt stress decreased the DFY, colour, coverage and density by about 50.78%, 6.73%, 32.20% and 34.54%, respectively. Under both conditions, the summer cut had the lowest values of forage production and turf quality characteristics compared to spring and autumn cuts, showing probable incomplete summer dormancy in the genotypes. Positive associations among crown diameter, plant height, leaf length, colour, coverage, density and stress tolerance index with forage yield indicated that simultaneous selection for both forage production and turf quality is feasible within this germplasm under both conditions. Based on the application of multivariate analysis, genotypes with possible utility as forage use or turf application were recognised, which can be used in future breeding programmes for developing synthetic varieties.