The Mediterranean basin (MB), a “climate hotspot”, is experiencing faster than average increases in global temperature and water deficit, as well as soil degradation, with detrimental impacts on food crop yield and pest/pathogen incidence. Hence, there is an urgent requisite for sustainable crop diversification strategies to promote crop resilience, soil quality conservation and pest/pathogen control. Intercropping is a strategy that has yet to be widely adopted. Presently, cereal–legume combinations represent the most common intercrops. Of relevance, a large number of medicinal and aromatic plants (MAPs), native to the MB, serve as potentially profitable indigenous resources for intercropping with food crops. Environmentally sustainable benefits of MB MAP intercropping with food crops have ironically been reported largely from research outside the MB. The present study aims to review the published literature from 2003 to 2023 on MAP intercropping with perennial nut/fruit crops and annual field crops in the MB. Published research is scarce but shows a promising upward trend, with 70% and 47% of intercropping studies with perennials and annual field crops, respectively, dated between 2020 and 2023. MAP intercropping shows potential in augmenting yield, pest/pathogen and weed control, soil health and cash crop quality, warranting further research with more widespread adoption in the MB.

The limited germplasm resources of hulless barley restrict the breeding of hulless barley with improved traits. Mutation techniques are an effective tool for generating variation for plant breeding studies. This study aimed to evaluate the impact of gamma-ray at different doses on certain seedling properties of M1 plants of two hulless barley genotypes, as well as determine the effective dose (ED50). The seeds of two hulless two-row barley genotypes, cv. Yalin and hulless barley line YAA7050-14, were irradiated with 100, 150, 200, 250, and 300 gray Gamma-rays delivered by a Cobalt 60 source along with non-irradiated control samples. Gamma-ray irradiation affects the seedling properties of M1 plants of both hulless barley genotypes significantly. The significant effect varied based on the doses, traits, and genotypes. While lower doses were found statistically identical to the control in the majority of qualities in the M1 generation, 250-300 gray gamma ray doses caused statistically significant decreases in the majority of characteristics studied in both genotypes. The effective doses (ED50) for hulless barley genotypes were determined by plotting growth reduction values of seedling lengths, then the polynomial regression equations were calculated for each genotype. It was determined that 50% growth reduction in shoot length was reached at 214.1 Gy and 253.4 Gy for cv. Yalin and line YAA7050-14, respectively.

Barley scald is caused by the fungal pathogen Rhynchosporium commune. This disease causes substantial losses in barley production areas of the world. In this study, seedling resistance of 198 barley landraces, 104 wild barley (Hordeum spontaneum) genotypes and two susceptible Turkish cultivars (Bülbül 89 and Efes 3) to 6 R. commune isolates was assessed in greenhouse experiments. Virulence differences among the R. commune isolates were observed. One sixrowed barley landrace (Yeşilköy 9052) was resistant to all six isolates. Another six-rowed barley landrace (genotype no 17) showed resistant reaction to 5 isolates. Fourteen barley landraces were resistant and susceptible to 4 and 2 isolates, respectively. Twenty seven genotypes of H. spontaneum numbered as 5, 6, 7, 8, 9, 11, 16, 20, 30, 31, 36, 37, 48, 50, 51, 56, 58, 59, 60, 62, 67, 79, 80, 83, 90, 94 and 101 were found resistant to all six isolates of R. commune. Apart from these genotypes, 19 genotypes numbered as 1, 2, 32, 33, 34, 42, 43, 49, 52, 64, 66, 76, 77, 78, 96, 97, 102, 104 and 107 showed resistance to 5 isolates and susceptibility to only 1 isolate. Two susceptible Turkish cultivars Bülbül 89 and Efes 3 were found susceptible to 96% of the scald isolates. Resistant barley landraces and Hordeum spontaneum genotypes can be used as sources of resistance against R. commune.

Barley is a crucial cereal crop with a diverse genetic heritage that includes landraces-traditionally cultivated variants that have adapted to varying agro-climatic conditions over centuries. Preserving barley landraces in genebanks is of utmost importance for safeguarding genetic diversity and aiding future breeding endeavors. This study aims an agro-morphological characterization of a selected collection of two row barley landraces conserved in the Osman Tosun Genebank. A total of 262 barley accessions were assessed in controlled field conditions to analyze various agro-morphological traits. The study unveiled notable disparities in the morphological traits of the genotypes, specifically in flag leaf anthocyanin, flag leaf sheath wax, spike shape, spike density, lemma color, grain color, lodging tendency, days to 50% flowering, plant height, spike length, spikelet quantity, and thousand grain weight, among other critical agronomical characteristics. To scrutinize the morphological disparities, the research utilized principal component analysis and ascertained that nearly 77.22% of the overall variance was accounted for by the first two principal components. The first four principal components accounted for 90.96% of the total variation, thus indicating significant genetic diversity among genotypes. The results of the cluster analysis revealed the presence of diverse genetic resources within the collection, with distinct groups of genotypes exhibiting similar traits being identified. The results of the agro-morphological characterization are a valuable resource for researchers and breeders, aiding them in making informed decisions regarding the management and application of barley landraces in breeding programs.

Rapid shoot and root growth at the early developmental stage of barley is critical for maximising yield and access to water and plant nutrients, particularly in dryland environments. Determining genotypic variation in shoot and root traits at the early seedling stage is essential for germplasm identification. In this study, widely grown old and new barley cultivars and wild barley genotypes were grown in sand media under greenhouse conditions for four weeks. The differences in shoot and root traits between the genotypes, the broad sense heritability and the genetic parameters of these traits were determined. The genotypes showed statistically significant differences for all the traits studied except number of leaves. Old cultivars had higher shoot length, while new cultivars had higher shoot fresh and dry weight. The old cultivars, new cultivars and wild barley genotypes were characterised by root length, root fresh weight and specific root length, respectively. A high correlation was found between root weight and root volume, and it was determined that root volume was more influenced by root thickness than root length. Shoot fresh and dry weight, root fresh weight, root volume and specific root length had the highest broad sense heritability. Among the genotypes, cv. Tokak 157/37 showed potential as a donor for root length and cv. Durusu for root weight and root volume in breeding studies.

The restricted genetic diversity observed in modern barley represents a significant obstacle to enhancing productivity. This study addresses this issue by characterising 445 six-row barley genotypes from the Osman Tosun Gene Bank in Türkiye. A comprehensive analysis of 22 agro-morphological traits, comprising 11 qualitative and 11 quantitative traits, was conducted to explore morphological, growth and phenological diversity. Principal component analysis identified four principal components, which collectively explained 72.86% of the total variance. Of these, the first two components accounted for 52.45%. Based on agro-morphological similarities, the genotypes were grouped into seven clusters. Clusters 5, 6, and 7 contained genotypes with high-yield traits, including early maturity, increased grain per spike, and higher thousand grain weight. The findings contribute directly to the expansion of the barley gene pool. Moreover, this study provides a comprehensive characterisation of the hitherto overlooked six-row barley germplasm present in Türkiye. This offers invaluable genetic resources for future breeding and molecular studies. Furthermore, the study compares the performance of three machine learning models (XGBoost, MARS, and Gaussian Processes) in predicting the harvest index from various traits. The XGBoost model demonstrated superior predictive ability, with the lowest RMSE (0.137), MAPE (0.222), and MAD (0.101) values, and was able to explain 99.8% of the barley variation. This research highlights the potential of machine learning algorithms in enhancing barley breeding by accurately predicting beneficial traits for yield improvement.