Journal of the Saudi Society of Agricultural Sciences最新文献

The durum wheat (Triticum turgidum L. ssp. durum Desf.) Landraces are a valuable source of natural germplasm for enhancing the genetic diversity of existing durum wheat cultivars. The study analyzed the genetic diversity of twenty-two durum wheat landraces including eight local Saudi landraces and fourteen introduced landraces using sixteen morphological descriptors and sequence-related amplified polymorphism (SRAP) markers. The results showed significant differences between the analyzed agro-morphological parameters and a large degree of genetic variation across the tested landraces. Principle components analysis (PCA) was used to determine agro-morphological relationships among different traits. The first six principal components (PCs) accounted for 78.47 % of the cumulative variability among 22 landraces. The PC1demonstrated variability in coleoptile anthocyanin coloration, straw pith, culm neck glaucosity, flag leaf glaucosity, ear glaucosity, and length of awn at tip relative to length of ear. Wheat landraces (L8, L14, L497, L569, L590, L594, L600, L601, and L602) showed increased diversity in dry region and contributed to PC1. A couple landraces had higher plant height (L12, L598, and L654), heading days (650, 656), and ear length (L12, L594, and L650) respectively. The dendrogram generated from the standardized morphological data separated the twenty-two durum wheat genotypes mainly into two clusters. The landraces 14, 600 and 602 grouped into separate cluster with strong correlation to ear glaucosity. Genetic diversity of these landraces was also evaluated using eight SRAP markers, with 482 amplified fragments and an average polymorphic information content (PIC) of 0.27. The dendrogram based on SRAP markers separated into two clusters with some diversified landraces (L8, 594, 602, 977, and L650). The Mantel test found no significant correlation (phenotypic or genetic) between 22 wheat durum landraces (r = 0.013, p = 0.84, =0.05). The results demonstrated the power of morphological and SRAP markers for detecting diversity among durum wheat landraces in the semi-arid region of Saudi Arabia. Thus, study provides insights into wheat diversity for better in-situ and ex-situ conservation and paves the road for their use in a Saudi durum wheat breeding program.

The application of kaolinite has been shown to be a viable strategy for protecting crops against excessive solar radiation and high temperatures. In coffee, this could occur during the nursery stage when the seedlings grow directly in full sun. The objective of the present study was to evaluate the effects of kaolinite particles when applied to coffee seedlings in full sun during the nursery stage and those of seedlings with no kaolinite applied grown directly in full sun and in shade. Two Coffea arabica L. variety Cenicafé 1 nurseries were established, and the following treatments were stablished: 1) K30: full sun with kaolinite at 30 g/L; 2) K60: full sun with kaolinite at 60 g/L; 3) SUN: full sun without kaolinite; and 4) SHADE: under a sunscreen with 60 % shade without kaolinite. The studied variables were dry mass, dry mass distribution, leaf characteristics, leaf physiological parameters, albedo, leaf temperature, and seedling mortality. Except for mortality, the variables were analyzed using a simple factorial design in generalized complete blocks and randomly using the Welch-James statistical test with bootstrapping. Mortality was assessed using a logistic binary response model with a X² test. The results showed that in comparison to the SHADE treatment, the SUN and K60 treatments resulted in more dry mass; in turn, the K60 treatment resulted in better RDM/TLA. In comparison to the SHADE treatment, both the K30 and K60 treatments resulted in greater increases in net photosynthesis rates, and in comparison, to the SUN treatment, these treatments also resulted in a greater increase in stomatal conductance, although only when the leaf abaxial temperature was greater than 30 °C. This result may have occurred based on the greater light reflection and the lower leaf temperatures obtained with kaolinite, in the K60 treatment. However, the seedlings that grew in full sun with and without kaolinite died three times more often than the seedlings in the shade. The previous suggests that it is not convenient to establish nurseries in full sun, with or without kaolinite, despite the physiological advantages and tolerance to high temperatures at the plant level.

Bird intake and damage to fruits of Phoenix dactylifera is a common problem in date palm cultivation regions. Though plant vegetative characteristics and fruit nutritional values influence frugivory behavior in passerines, there is little knowledge about these parameters for sparrows feeding on dates, as most previous studies have focused on the impact of farm organization and location on the feeding choice made by sparrows. This study aimed to examine the effects of date palm tree traits and its fruit morphology and biochemical traits on the level of damage caused by hybrid sparrows to date fruits of three different date palm cultivars. In a traditional date palm plantation, three date varieties (Degla-Beida, Deglet-Nour and Ghars) were analyzed. The estimates of date production loss were correlated to several tree morphometrics and fruit morphological and biochemical traits, including the number of bunches/tree, bunch height, number of pedicels/bunch, number of dates per strand, total production/tree, and date fruit traits (length, width, weight, volume, pulp weight, ratio pulp weight/date weight, sugar content, water content and pH). We demonstrated that sparrows were attracted to bunches with low height and high fruit density, but they showed no interest to number of bunches per tree, number of pedicels per bunch, total number of dates and production per tree. Regarding date morphology, large and heavy dates were more likely to be selected by sparrows, although an unclear relationship was found between production loss per tree and date length, width and volume. In terms of fruit biochemical traits, sparrows damage rates increased with the increase in fruit pH, moisture, and total and reducing sugars. The average rate of lost dates per tree was 9.2 ± 7.66%, 8.4 ± 5.16%, and 3.9 ± 1.71% for Ghars, Deglet-Nour, and Degla-Beida, respectively. Significant differences were observed between cultivars in the amounts of damaged dates still on bunches or fallen on the ground. The hierarchical choice of dates by sparrows was also confirmed. Our results showed that soft dates were more preferred by sparrows than semi-soft and dry ones. The findings of this study indicated that it is necessary to provide extensive protection for highly attacked cultivars in palm groves.

The objective of this study was to determine some geometric, gravimetric, and mechanical properties of lemon seeds and how these were influenced by moisture content under a range of post-storage processing conditions. The skin, pulp, and seed fractions of lemon fruits were determined. The seed fraction had a value of 1.86% with an average hull/seed ratio of 38.92%. Seed moisture content was varied by drying with hot air from the storage condition (8.28% d.b.) to a minimum moisture condition (1.31% d.b.). The drying kinetics were adequately described using a two-term exponential model, which suggested the presence of two distinct internal seed resistances to moisture transfer related to its composition. Furthermore, with the exception of thickness, all geometric properties evaluated tended to decrease as moisture content decreased, especially at the driest level evaluated. Within these, the most important variations were found in theoretical volume (24.20%) and width (22.28%), for a moisture content change of 84%. Gravimetric and mechanical properties exhibited the same tendency, with the exception of true density, which increased, and bulk density and bulk porosity which did not change significantly. It is noteworthy that rupture energy decreased by approximately 50% as the moisture content was reduced from 8.28 to 4.62%. In conclusion, drying lemon seeds generated smaller and more fragile structures that could benefit subsequent processes such as dehulling or milling, among others, but could also negatively affect seed movement through undesirable breaking. Therefore, knowledge of the properties studied in this work will be useful for the design of manufacturing and storage equipment, as well as handling and process operations.

Festuca arundinacea Schreb. as an important turf widely exposed to biotic and abiotic stresses. Therefore, optimization of an efficient in vitro culture and transformation method to create optimal traits and tolerance against stresses as a major problem, is essential. In this research, in order to callus induction, embryos of ‘Barlexas II’, ‘Barvado’, ‘Coronado TDH’, and ‘Finelawn Elite’ cultivars were transferred on callogenesis medium containing 0–15 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and after callus formation, the explants cultured on the regeneration medium added with 0–1.75 mg/L 6-benzyladenine (BA). Out of the four cultivars tested, ‘Barvado’ in 7.5 mg/L (51.83 %), and ‘Finelawn Elite’ in 10 mg/L 2,4-D (54.06 %) had better callusing, respectively. However, regeneration percentage was higher in ‘Barlexas II’ (73.15 %) and ‘Finelawn Elite’ (70 %) in 0.5 mg/L BA. Transformation was done in Murashige and Skoog (MS) modified medium by Agrobacterium tumefaciens strain LBA4404 harboring binary vector pCAMBIA 2301. Transgenic calli and plantlets were confirmed by GUS gene expression as non-destructive, non-invasive and useful marker. Maximum rate of callus transformation was shown on modified medium type 11 for ‘Coronado TDH’ and ‘Barlexas II’ (23 % and 22 %, respectively). When the calli samples were placed on the selection media, a high rate of calli (with no successful activity of neomycin phosphotransferase II (NPTII)) had not the ability to regenerate and died. Therefore, the highest rate of regenerated transgenic plantlets containing NPTII and GUS genes (6 %) was belonged to medium type 6 and ‘Coronado TDH’.

Peanut (Arachis hypogaea L.) is a major crop grown on 24 million ha around the world for edible oil and food. Globally, peanut varieties with high yield potential and adaptation ability have been enhanced, developed, and approved for cultivation. The improved varieties have diverse maturity durations and have disease resistance, drought tolerance, increased oil content, and improved quality traits for food uses. Currently, the limitations of productive agricultural lands and the scarcity of available water are the critical factors contributing to the gap in food production worldwide. In this direction, a two-year-long field study was conducted during the summer seasons of 2019 and 2020 to study the ability to cultivate certain peanut varieties, including Giza 6, Giza 5, and Gregory. Three water regimes100, 80, and 60% of crop water requirement (CWR) were applied using two methods of irrigation application (drip and sprinkler) in new agricultural expansion areas located north of Cairo city. The obtained results confirmed that increasing the water deficit from 100% to 60% of CWR significantly reduced all peanut growth traits such as biomass by 14.3%, pod by 14.2%, and seed by 7.8%, but the 80% water regime recorded the highest oil content. Regarding the irrigation systems, the drip irrigation system surpassed the sprinkler system in both successive seasons in all studied variables. Giza 5 variety, along with 60% of CWR, recorded the highest water productivity for biomass and pod yields. The Giza 6 variety was the most tolerant variety based on the stress tolerance index (STI), whereas the Gregory variety was the least drought-tolerant variety.

Moringa oleifera is a plant valued for its properties and applications in Ethnomedicine. It is cultivated in India, tropical Africa, and America; some regions use their different tissues as food supplements. Although germination can increase seedlings' phytochemical content, few studies have described the phytochemical content of moringa seedlings during early growth. This study aimed to investigate and discuss the limited information dealing with moringa seed germination, sprout production, and seedlings' chemical composition. This bibliographical research was systematically and thoroughly conducted using some of the most internationally-recognized databases. M. oleifera plants are characterized by their ability to grow under adverse environmental conditions. Although they generally germinate at rates greater than 70%, this response depends on the altitude, light periods, temperature, and nutrient availability. Pre-germination treatments have also been reported to help improve germination yields; the most common is soaking exposure. The production of M. oleifera sprouts is a viable option for obtaining functional food as this process can increase the content of nutrients (e.g. lipids, proteins) and phytochemicals (glucosinolates and phenolic compounds). Also, sprouts can be used as additives to enrich conventional foods. It is concluded that there is little scientific information describing the germination process and the chemical composition of both moringa seeds and moringa sprouts. Therefore, it is a niche opportunity to build new research that helps fill the informational gaps mentioned above. Meanwhile, it is envisioned that biotic or abiotic agents might modulate the germination process and their chemical compounds.

Mangrove endophytes have been widely studied for several years and Avicennia marina endophytic fungi is known for its remarkable activity against many plant pathogens. Tomato is an important food crop in Saudi Arabia but it is susceptible to fungal diseases.The control of these phytopathogens through fungicides and pesticides is temporary. Thus, this study is aimed to isolate mangrove plant i.e. Avicennia marina endophytic fungal antagonists, characterize their phylogenetic positions and determine their antagonistic activities against tomato fungal pathogens. This study isintended to find a suitable alternative method to control or limit the spread of tomato diseases by using endogenous fungi of mangroves. Ninety fungal pathogens were isolated from three tomato farms in different regions of Riyadh city, Saudi Arabia. In addition, 40 endophytic mangrove i.e. Avicennia marina fungi were isolated from the eastern and western mangrove stands of the Kingdom of Saudi Arabia using potato dextrose agar, Czapek dox broth and malt extract broth media. These fungal strains were phylogenetically classified into at least sixteen genera based on 18S rRNA gene sequencing analysis. The antagonistic strains were screened via a Dual Culture Plate Assay and filter paper disc method. This study showed that endophytic fungal isolates have an antagonistic effect on most tomato pathogenic fungi. Cladosporium sphaerospermum had the highest inhibition while Trichoderma asperellum showed least antagonism against Avicennia marina endophytic fungi. This study proved that endophytic fungi present in Avicennia marina can control many tomato pathogens and their respective diseases. This work also cleared many aspects regarding the use of Avicennia marina endophytic fungal strains as potential biocontrol agents. Also, the diversity observed by these endophytic fungal strains from different areas of Saudi Arabia opened many doors for future research in the control of fungal pathogens.