Effect of planting dates and cutting treatments on production of dual purpose barley in the Central Region of Saudi Arabia

The traditional system of wheat and barley cultivation in Saudi Arabia was based on the utilization of vegetative growth at 50 - 60 days as forage for live stock then allow the crop to produce grains. This system was suitable for local cultivars to delay flowering to frost free periods and reduce their ability to lodging. However, the introduction and use of improved short cultivars has reduced the value of this system in recent wheat and barley production practices. This study was designed to evaluate the use of barley as a dual-purpose crop. The objectives were to determine the suitable planting date, vegetative stage for forage utilization and the appropriate cultivars for this purpose. Six different cultivars, including the commercial cultivar, Justo and a local cultivar from the Asir Region, were planted in three dates 1st Nov., 25th Nov. and 20th Dec. and three cutting treatments at the age of 50 and 65 days and no cut treatment as a control. The experiment was laid out as in split-split plot design with four replications for two successive seasons 95/96 , 96/97. Results of the two seasons data have shown that the planting date at 1st Nov. was significantly higher than the other planting dates in forage, grain yield and straw production. Cutting for forage at age of 65 days was superior (5.17 tons/h) to cutting at the age of 50 days. (2.1 tons/ h). Utilization of vegetative growth for forage at the age of 65 days has resulted in a reduced grain yield ranging from 12 and 59 % in the first and the third planting dates respectively. Whereas the reduction in straw yield was greater ranging from 35 to 58% in the first and the third planting dates respectively. Significant variations among cultivars were observed in dry forage and grain yields. The cultivar Justo was the best in grain yield, while the local cultivar was the best in forage yield. The cultivars, Giza 121 and Giza 123 , had very good forage and grain yields while the cultivar, Sahrawi produced a good forage yield with excellent recovery after harvest which indicated that these three cultivars could be used as dual purpose cultivars under the conditions of the Central Region of Saudi Arabia

Analysis of Salinity Tolerance in Tomato Introgression Lines Based on Morpho-Physiological and Molecular Traits

The development of salt-tolerant tomato genotypes is a basic requirement to overcome the challenges of tomato production under salinity in the field or soil-free farming. Two groups of eight tomato introgression lines (ILs) each, were evaluated for salinity tolerance. Group-I and the group-II resulted from the following crosses respectively: Solanum lycopersicum cv-6203 × Solanum habrochaites and Solanum lycopersicum M82 × Solanum pennellii. Salt tolerance level was assessed based on a germination percentage under NaCl (0, 75, 100 mM) and in the vegetative stage using a hydroponic growing system (0, 120 mM NaCl). One line from group I (TA1648) and three lines from group II (IL2-1, IL2-3, and IL8-3) were shown to be salt-tolerant since their germination percentages were significantly higher at 75 and 100 mM NaCl than that of their respective cultivated parents cvE6203 and cvM82. Using the hydroponic system, IL TA1648 and IL 2-3 showed the highest value of plant growth traits and chlorophyll concentration. The expression level of eight salt-responsive genes in the leaves and roots of salt-tolerant ILs (TA1648 and IL 2-3) was estimated. Interestingly, SlSOS1, SlNHX2, SlNHX4, and SlERF4 genes were upregulated in leaves of both TA1648 and IL 2-3 genotypes under NaCl stress. While SlHKT1.1, SlNHX2, SlNHX4, and SlERF4 genes were upregulated under salt stress in the roots of both TA1648 and IL 2-3 genotypes. Furthermore, SlSOS2 and SlSOS3 genes were upregulated in TA1648 root and downregulated in IL 2-3. On the contrary, SlSOS1 and SlHKT1.2 genes were upregulated in the IL 2-3 root and downregulated in the TA1648 root. Monitoring of ILs revealed that some of them have inherited salt tolerance from S. habrochaites and S. pennellii genetic background. These ILs can be used in tomato breeding programs to develop salt-tolerant tomatoes or as rootstocks in grafting techniques under saline irrigation conditions

Vegetation Composition of the Halophytic Grass <i>Aeluropus lagopoides</i> Communities within Coastal and Inland Sabkhas of Saudi Arabia

Sabkhas are unique, highly saline ecosystems, where specially adapted plants can grow. Aeluropus lagopoides (L.) Thwaites is a halophytic forage plant growing in salt marsh habitats of inland and coastal sabkhas of Saudi Arabia. The present study provides an analysis of vegetation composition and distribution of the A. lagopoides community in five different regions within Saudi Arabia, emphasizing the environmental factors that affect species distribution. The floristic survey revealed the presence of 48 species, belonging to 26 families. Poaceae, Chenopodiaceae, Mimosaceae, Zygophyllaceae, and Asteraceae are the largest families (50% of total species). Phanerophyte, followed by chamaephytes, are the most frequent forms, indicating a typical saline desert life-form spectrum. The vegetation analysis revealed the dominance of A. lagopoides in all locations, where it was the most dominant species in Qareenah, Qaseem, and Salwa locations, and the second most dominant species in Jouf and Jizan locations. The flourishment of this halophytic grass within a wide soil range in sabkhas revealed its adaptability to the harsh environment, which could be ascribed to its structural adaptations and modifications, as well as the phenotypic plasticity. The Qareenah and Qaseem locations attained the highest species richness and evenness, while the Jizan location was the least diverse. Within the studied locations, other highly salt-tolerant species were determined with high abundances, such as Suaeda aegyptiaca (Hasselq.) Zohary, Zygophyllum album L.f., Tamarix nilotica (Ehrenb.) Bunge, Cressa cretica L., and Salicornia europaea L. The soil analysis showed a significant variation for all parameters among the studied locations, except for pH, chloride, and clay content. The Qaseem location revealed the highest values of most soil parameters, while the Jizan location showed the lowest. The canonical correspondence analysis (CCA) showed that the community structure and diversity are mainly affected by the soil salinity and moisture. Due to the economic potentialities of A. lagopoides as a forage plant and sand stabilizer, the conservation of its habitats is of vital importance. In addition, this grass could be integrated as a promising forage candidate that can be planted in saline-affected areas, even in the summer dry season

Molecular mapping of a novel QTL for resistance to cereal cyst nematode in F4 wheat population

A wheat line selected from an off-type plant (Lnm136) was found to be resistant to Heterodera avenae (cereal cyst nematode, CCN). A F4 population developed by crossing this line with a CCN susceptible genotype, Ksu118, was used to study the map location of the CCN resistance. The results showed that the most significant QTLs for the cereal cyst nematode (CCN) score were identified on five chromosomes. One of the QTLs was located on chromosome 1B and linked closely to Xwmc85 based on composite interval mapping. A novel locus accounting for up to 70% of the resistance to CCN was mapped to chromosome 1B of Lnm136, by association with the microsatellite marker Xwmc85-1B. The selected CCN resistant F4 lines showed introgression for molecular markers identified to be linked with the CCN resistance locus Xwmc85-1B. This QTL on chromosome 1BS in the interval of Xwmc85–Xgpw4331 appears to be a major novel resistance locus. Multiple regression analysis showed the importance of the 1B region and marker-assisted selection for the favorable allele at this region should improve the resistance against CCN. The introgression lines can be used for marker-assisted transfer of Xwmc85-1B to elite wheat cultivars

Assessing the Suitability of Selection Approaches and Genetic Diversity Analysis for Early Detection of Salt Tolerance of Barley Genotypes

Assessment of the salt tolerance of a large genotype collection at the early growth stages may assist in the fast-tracking improvement of salt-tolerant barley genotypes in breeding programs. This study aimed to investigate the ability of traits related to seed germination ability and seedling growth performance with helping of nine sequence-related amplified polymorphism (SRAP) markers to detect the salt tolerance of 70 barley genotypes during the early growth stages. The different genotypes were exposed to three salt concentrations (0, 100, and 200 mM NaCl) and evaluated for salt tolerance by looking at germination percentage, germination index, and mean germination time during eight days as well as the lengths and weights of seedling shoot and root after 21 days from sowing. The results showed that genotypic variations in germination ability and seedling growth performance obviously appeared under 200 and 100 mM NaCl, respectively. The germination traits exhibited a strong correlation among themselves, whereas they had a poor correlation with seedling traits. A strong and positive correlation was only observed for shoot fresh weight with shoot length and root fresh weight under salinity conditions. Principal component analysis revealed that the first two components, which explained 53% of the total variability, succeeded to identify the genotypes with high salt tolerance during only one stage (germination or seedling stage) and both stages. Cluster analysis based on the stress tolerance index of germination and seedling traits grouped 70 genotypes into four key clusters, with genotypes grouped in cluster 1 and cluster 2 being salt tolerant during the germination stage and moderately tolerant during the seedling stage; the opposite was found with the genotypes grouped in cluster 4. According to Ward’s method, the salt tolerance of genotypes that ranked as most salt-tolerant (T) or salt-sensitive (S) remained almost unchanged during germination and seedling stages. In contrast, a change in salt tolerance with both stages was found for the genotypes that ranked as moderately salt-tolerant (MT) and salt-sensitive (MS) genotypes. The nine SRAP markers divided the tested genotypes into two distinct clusters, with clusters B had the most T and MT genotypes. Finally, using appropriate statistical methods presented in this study with SRAP markers will be useful for assessing the salt tolerance of a large number of barley genotypes and selecting the genotypes tolerant of and sensitive to salinity at the early growth stage

Molecular Characterization and Functional Localization of a Novel SUMOylation Gene in Oryza sativa

Small ubiquitin-related modifier (SUMO) regulates the cellular function of diverse proteins through post-translational modifications. The current study defined a new homolog of SUMO genes in the rice genome and named it OsSUMO7. Putative protein analysis of OsSUMO7 detected SUMOylation features, including di-glycine (GG) and consensus motifs (&Psi;KXE/D) for the SUMOylation site. Phylogenetic analysis demonstrated the high homology of OsSUMO7 with identified rice SUMO genes, which indicates that the OsSUMO7 gene is an evolutionarily conserved SUMO member. RT-PCR analysis revealed that OsSUMO7 was constitutively expressed in all plant organs. Bioinformatic analysis defined the physicochemical properties and structural model prediction of OsSUMO7 proteins. A red fluorescent protein (DsRed), fused with the OsSUMO7 protein, was expressed and localized mainly in the nucleus and formed nuclear subdomain structures. The fusion proteins of SUMO-conjugating enzymes with the OsSUMO7 protein were co-expressed and co-localized in the nucleus and formed nuclear subdomains. This indicated that the OsSUMO7 precursor is processed, activated, and transported to the nucleus through the SUMOylation system of the plant cell

Molecular detection of QTLs for flour quality traits in two doubled haploid populations in spring wheat under heat stress

Wheat four quality is a complex group of traits of tremendous importance to wheat producers, end-users and breeders. Eight four quality traits; four protein content, wet gluten content, gluten index, dry gluten content, falling number, ash content, test weight and four moisture were measured in two doubled haploid populations (Yecora Rojo X Ksu106 and Klassic × Ksu105) at Riyadh and Al-Qassim locations under heat treatments. Single-nucleotide polymorphism markers have been used to determine the number of QTLs controlling the four quality traits in both populations. Analysis of variance revealed high signifcant diferences (P<0.01) for all traits among wheat genotypes and between locations in both populations. The wheat genotypes × location interaction was high signifcant in both populations. A total of 58 additive QTLs were detected for the eight four quality traits in the Yecora Rojo × Ksu106 population at Riyadh and Al-Qassim locations under heat treatments. They were mainly distributed over the 21 wheat chromosomes except 4B and 4D chromosomes. Moreover, in Klassic × Ksu105 population, there were 69 additive QTLs identifed over the full set of chromosomes except 3D chromosome under two locations. This study will facilitate the generation of improved wheat varieties with good quality via molecular markerassisted breeding

Identification of genotyping-by-sequencing tags associated with bread-making quality traits in spring wheat under heat stress

The bread-making quality traits of bread wheat underlie into genetic make-up of a variety and are infuenced by environmental factors and their interaction. Identifying QTL that control bread-making traits in wheat under heat stress may help to develop cultivars that are improved for those traits. Two doubled haploid (DH) populations (Yecora Rojo×Ksu106 and Klasic× Ksu105) were used to identify QTL for eight bread-making traits in wheat under heat stress. The phenotyping of bread-making traits was performed under normal and heat stress conditions in Al-Qassim and Riyadh locations, Saudi Arabia. Single nucleotide polymorphism (SNP) markers have been used to determine the number of QTLs controlling the bread-making traits. The genetic analysis of bread-making traits showed considerable variation for measurable traits with transgressive segregation under normal and heat stress conditions in both locations. A total of 60 QTL explained 10–22% of phenotypic variation in the population (Klassic × KSU105). In the population (Yecora Rojo× KSU106), the 98 QTL explained 10–23% of phenotypic variation. In the population (Klassic×KSU105), eleven co-located QTLs were identifed on chromosomes 2A, 3A, 3D, 5B and5D. The BBS QTL under heat stress co-located with QTLs for BCC and BSY under heat stress and normal conditions, respectively, in Riyadh location. Nineteen QTL clusters were identifed on chromosomes 1D, 2A, 2B, 2D, 3B, 3D, 4A, 4D, 5A, 5B, 6A, 7A and 7D based on Map 2 in the population (Yecora Rojo× KSU106). Interestingly, one locus (JD_c4438_839) on the chromosome 5D was identifed in both populations and was considered stable QTL. This locus was associated with QLFV.hs and QSLFV.hs in the population (Klassic× KSU105) and QLFW.n in the population (Yecora Rojo×KSU106). The fnding of SNP marker (JD_c4438_839) has an important signifcant for marker-assisted selection of bread-making quality traits under heat stress

Phylogenetic Analysis of Ryegrass (<i>Lolium rigidum</i>) Populations and the Proliferation of ALS Resistance in Saudi Arabia

Morphological and simple sequence repeat (SSR) approaches were used to determine the genetic diversity of 29 ryegrass (Lolium rigidum) genotypes belonging to eight populations collected from several regions in Saudi Arabia. In this study, 50 in Silico-developed SSR markers derived from genomic and expressed sequence tag (EST) microsatellites were examined. Analysis of variance showed highly significant differences in all studied traits. Cluster analysis based on the morphological data of the 29 Lolium genotypes and using PAST (paleontological statistics) software was performed. According to the results, clustering was based mostly on genotype location. The sensitive genotypes for herbicide were clustered in one group. In addition, using EST-SSR markers, we observed the existence of a considerable number of genetic variations among Lolium genotypes. From these markers, only 31 produced reasonable amplification products. The results showed that 23 SSR markers revealed that 74.19% were polymorphic. The number of alleles detected per primer ranged from one to five in the primer LTC SSR1. The tested primers amplified 1434 bands across eight populations, with an average of 46.26 bands per primer. The polymorphism information content (PIC) values ranged from 0.11 to 0.76 for the primers LT EST-SSR5 and LTC SSR1. The unweighted pair group method with arithmetic average (UPGMA) clustering of the 29 genotypes representing eight populations was based essentially on their locations and herbicide-tolerance levels. Most of the populations formed into four clusters, together representing genotypes. Moreover, the tolerant populations were distinguished from the sensitive ones. The relationship between the genetic diversity and geographical source of Lolium rigidum populations of Saudi Arabia was revealed through this study. The results showed that the efficiency of developed SSR markers are transferable across species. They have been helpful to assess the genetic diversity of the ryegrass population as this could be applied to differentiate between tolerant and sensitive populations of ryegrass