Journal of the Saudi Society of Agricultural Sciences最新文献

In this study, the resistance of selected canola genotypes to the mustard aphid Lipaphis erysimi (Kaltenbach) was investigated. Molecular characterization of plant resistance was conducted, and genetic variability was observed between the resistant (KS-75) and susceptible (Abaseen) genotypes of brassica. Three RAPD markers were identified that were associated with the resistance. This study was conducted to compare the genetic data between two genotypes (KS-75 resistant and Abaseen susceptible), with an average of 4.3 bands per primer. The amplification bands per primer ranged from 9 to polymorphic fragments of 8, with fragment sizes ranging from 450 to 1700 base pairs to 9 kilo base pairs (kbps). Amplification of the largest fragment in 9 kbps using four primers (A 1–12, B 1–12, K 1–12 and L 1–12) resulted in a mean 92 percent identity index between the first two resistant and susceptible genotypes. KS-75 resistant had the highest mean genetic diversity of 92 percent, while Abaseen susceptible had the lowest mean genetic diversity of 8 percent. Out of the three markers tested, two were found to be positively associated with aphid resistance, while one was negatively correlated. These markers can be used to help develop a pre-emptive strategy for aphid resistance in brassica species, without having to simultaneously select for yield and quality related traits.

Tuta absoluta is an invasive, oligophagous pest that has been recently reported from Pakistan. Although originated from South America, it has now introduced and spread in almost all the tomato growing areas of the globe including Pakistan. Therefore, delta type pheromone traps containing synthetic 0.8 mg pheromone along with various colored light traps i.e., red, blue, golden, white, and green were evaluated for the monitoring and management of T. absoluta. Weekly observations were taken for the mean capture of T. absoluta moths in traps along with mean infestation percentage on leaves, stems and fruits of tomato. Results indicated that all the traps were found effective to attract T. absoluta moths, but they vary in their effectiveness to capture moths. Pheromone traps capture only males, whereas light traps attracted both the sexes. Significantly the highest number of males were captured in female synthesized pheromone traps, followed by golden color light traps, whereas red color light traps capture least number of males. Males captured in blue, white, and green color light traps were not significantly different from each other. Significantly the highest number of females were captured in golden color light traps, followed by blue color trap, whereas females capture in white and green color light traps were not significantly different from each other. The least number of females were captured in red color light traps. The tomatoes grown in golden color light and pheromone traps significantly suffered the lowest infestation, followed by blue, white, and green color light traps, whereas maximum damage was observed in red color light trap treatment. Only temperature showed a significant but very weak influence on the performance of various traps to attract T. absoluta moths. Therefore, studies should be undertaken to evaluate various combination of light traps with pheromone to maximize the capture T. absoluta moths, that could not only help in its early monitoring and detection but could lead to its mass destruction.

‘Mejhoul’ date cultivar originated from Morocco and largely spread around the world. It is of high commercial value and is considered to be one of the best-exported dates concerning its fruit quality and size in comparison with other cultivars. This study aims to investigate variations within the physicochemical and microbiological characteristics of ‘Mejhoul’ dates sampled from its original growing areas in Morocco and other countries, where the cultivar is expanded in the recent years. Dates samples were collected from the most important production areas of the ‘Mejhoul’ cultivar in Morocco (Figuig, Bouanane, Boudnib, Difat Ziz, Rissani and Zagora) and the United States of America, Kingdom of Saudi Arabia, Jordan and Palestine. Variance analysis of pH, moisture, ash and sugar content show a significant difference (p < 0.05) within ‘Mejhoul’ cultivar samples. Statistical analysis (Principal Component Analysis “PCA”) allows the classification of samples into three groups. The first group holds ‘Mejhoul’ samples from Morocco, including Figuig, Boudnib and Difat Ziz, characterized by high water content and high density of TVC and Yeasts. The second group is composed of all international samples (Palestine, Jordan, USA and KSA) in addition to samples from Rissani (Morocco), presents reverse characteristics compared to the first group. The third group includes ‘Mejhoul’ from Bouanane and Zagora (Morocco). Despite the availability of favorable conditions, making Morocco an ideal area for ‘Mejhoul’ production. However export of this date cultivar remains limited from Morocco due to uncontrolled production techniques and environmental factors.

Due to global warming, animal’s heat tolerance and adaptability characteristics to hot environmental conditions are attracting more research interest. The current experimental study was actually designed to evaluate and compare the heat tolerance efficiency of two purebred Saudi sheep when exposed to heat stress conditions under a biometeorologically-simulated environment similar to Kingdom of Saudi Arabia (KSA) semi-arid environment. A total of 20 healthy male growing lambs of Najdi and Naimi breed with an initial body weight of 24.71 ± 4.65 Kg and 4 month-old were used in a 2-phases experiment. During the preliminary phase (lasted for 3 weeks), lambs were placed under a stable thermoneutral condition. Meanwhile, simulation of the external environment was performed using climatic-controlled chambers during the experimental phase (lasted for 8 weeks). Several meteorological [ambient temperature (Ta), relative humidity (RH) and temperature humidity index (THI)] and thermophysiological [rectal temperature (Tr), skin temperature (Tsk), respiratory rate (RR), heat tolerance coefficient (HTC), adaptability coefficient (AC), internal (BTG_in), external (BTG_ex) and total (BTG_to) body thermal gradients] measurements were recorded at weeks 0, 4 and 8. The obtained meteorological data showed that the prevailed conditions in the climatic chamber exhibited (P < 0.05) elevated values compared to the chambers with control or thermoneutral conditions, which indicated that all lambs had undergone a different level of surrounding conditions, which was our goal in the first place. Notably, the obtained findings of all variables showed irrespective to the breed the same trend as they all were affected (P < 0.05) at the 4th weeks and slowly returned to their steady values by the 8th weeks, especially body temperatures. Under such hot climatic condition, lambs showed as well some breed difference, where Naimi lambs kept in eliciting (P < 0.05) higher values of RR, AC, and BTG_to as well as lower values of HTC compared to their Najdi associates. In conclusion, the outcomes might collectively enable us to initially recommend selecting Najdi breed over Naimi breed for herding under the hot environmental conditions of KSA. However, identification of genes responsible for acquiring heat tolerance ability of Najdi compared to Naimi is highly recommended in future studies.

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’.