Increased salinity from irrigation and poor drainage has led to reduced production in semi‐arid and arid irrigated areas of the world. The narrow genetic variation among domestic barley (Hordeum vulgare L.) genotypes slows progress in developing varieties tolerant to biotic and abiotic stresses. A wild barley relative (H. bulbosum L.) is a genetic resource with tolerance to multiple stress conditions, especially salinity. New germplasm added to the USDA barley collection allows novel breeding opportunities. However, crosses between these species require embryo rescue. Crosses were made between diploid and tetraploidized domestic barley ♀ and tetraploid bulbous barley ♂. Immature embryos were rescued and placed on Murashige and Skoog (MS) or Gamborg's B‐5 (B‐5) media (no plant growth regulators, PGRs). Analysis of variance of families showed significant effects for the genotype × medium interactions, indicating each genotype responded to each medium type independently. Significant effects were observed for some traits due to both genotype and medium; and significant effects between media for some traits were observed indicating that those traits were affected by media type. Murashige and Skoog was found to be the better medium for most crosses compared to B‐5. Generally, results from this study indicated that it is difficult to draw broad conclusions about the most suitable medium composition for a broad spectrum of genotypes due to individual genotypes responding differently to the media type. Subsequent manuscripts by these authors will address the success of fertile crossed  progeny.

Salinity is a critical challenge facing productivity of barley around the world, necessitating the development of salinity tolerant varieties. Screening genotypes of two barley species during germination and seedling growth stages was conducted to identify genotypes with superior performance under saline stress conditions. Five genotypes of domestic barley (Hordeum vulgare L.) and six of wild barley (H. bulbosum) were used in this study. Genotypes were germinated in solutions of 0, 1.0, 1.5, and 2.0% NaCl (0, 171, 257, and 342 mM NaCl). Shoot and root length were recorded 10 d after germination. Upon reaching the three-leaf stage, seedlings were irrigated with 500 mM NaCl solution for 3 wk to evaluate salt tolerance using the growth index. The analysis of variance showed there was a high genetic variation among genotypes.Only genotypes PI220054, PI227242, and PI420909 of wild barley species germinated at the 2% NaCl salinity level. All domestic barley genotypes failed to germinate at 2% NaCl salinity and showed reduction of root and shoot length greater than wild barley genotypes under saline conditions. Mean root and shoot lengths decreased as the level of NaCl increased for all genotypes. This condition was more intense in domestic than wild barley genotypes. Seedling screening showed PI268243 had the greatest growth index compared with the other genotypes. The PI227242 genotype had the greatest growth index among wild barley genotypes. Regression analysis indicated that there was no relationship between salt tolerance at germination and seedling growth stages.

Salinity is one of the most detrimental abiotic stresses affecting crop productivity worldwide. To identify barley (Hordeum vulgare L.) genotypes with satisfactory production under increased salinity, screening must focus on multiple phenological stages, specifically the earliest stages (germination and seedling), when plants are most vulnerable to stress. This experiment was conducted in a greenhouse to assess salinity tolerance of 161 genotypes (34 genotypes of 2× H. vulgare crosses; 116 genotypes of 4× H. vulgare crosses, and 11 parents). Beginning at the third leaf stage, seedlings were irrigated with solutions of 0, 100, 200, and 300 mM NaCl for 21 d.Analysis of variance showed significant effects due to genotype, salinity level, and their interaction for shoot dry weight (SDW). Overall, SDW showed negative association with plant height, whereas it was positively associated with tiller number, fertility, 100-seed weight, and grain yield. Mean SDW of all families decreased as salinity treatment level increased. Families varied in SDW and salinity susceptibility index (SSI) at 300 mM salinity treatment. Diploid Families 2 and 3 had the greatest SDW and lowest SSI (<1). Thirty percent of crosses from tetraploid Family 2 yielded the greatest SDW, whereas the same proportion of crosses from tetraploid Family 4 showed the greatest salinity tolerance as measured by SSI. These crosses, as well as the female parents, are valuable germplasm for improving salinity tolerance in barley breeding programs.

Salinity is one of the most important challenges facing future global barley (Hordeum vulgare L.) productivity, as it causes major reduction in germination, growth, grain yield, and quality. Screening germplasm for salinity tolerance at germination is vital to breeding programs because germination is the first stage of plant growth and occurs near the soil surface where salt can accumulate in high concentrations. This experiment was conducted to assess salinity tolerance of 249 genotypes (64 diploid (2×) H. vulgare crosses; 174 tetraploid (4×) H. vulgare crosses; and 11 parents) at the seed germination stage. Salinity treatments applied at imbibition included concentrations of 0, 100, 200, and 300 mM salinity and were maintained for 10 d. Analysis of variance of all families indicated significant (P ≤ .001) genotype × salinity interaction for final germination percentage (FG%), corrected germination percentage (CG%), and germination index (GI) at all treatment levels, indicating high genetic variation for salinity tolerance among screened genotypes. The mean of all measured parameters (FG%, CG%, and GI) decreased as salinity concentration increased. These responses can be used to identify genotypes with salinity tolerance at germination. At 300 mM salinity, progenies in 2× Families 1 and 2 were 14.3 and 12.5% saline tolerant, respectively. A total of 29 progenies from 4× families were tolerant to 300 mM treatment at germination. These progenies would have an economic value for improving barley tolerance for salinity.

A laboratory experiment was conducted in the Department of Field Crops/College of Agriculture/Tikrit University to determine the effect of seeds priming of five barley cultivars (Arevat, Alwarkaa, Alhadher, Buraq, Rihan) with four concentrations (0, 60, 120, and 180 ppm) of kinetin on the parameters of germination and seedling growth. The factorial experiment was laid out in completely randomized design (CRD) with four replications. There was a significant effect on all studied traits due to cultivars, kinetin, and cultivars x kinetin interaction, which indicated high genetic variation among evaluated barley cultivars. Buraq cultivar was superior to all cultivars in all studied traits: germination percentage, speed, and vigor, root and shoot length, and dry weight with values of 98.38%, 48.76, 56.19, 10.35cm, 18.47cm, and 0.03776g, respectively. All concentrations of kinetin were significantly superior to the control treatment for all studied traits. Seeds treated with 60 ppm of kinetin gave the highest values of germination percentage (90.75%) and root length (10.81cm), while the concentration 120 ppm gave highest value of germination vigor (45.60) and shoot length (19.96 cm). The combination of (Buraq x 60 ppm) was superior for all studied traits except the trait of total dry weight, where the interactions of Buraq, Arevat, and Rihan cultivars with 120 ppm of kinetin were superior.