Chemical control and herbicide resistance of hairy fleabane [Conyza bonariensis (L.) Cronquist] in Jordan

Two field experiments were conducted to evaluate the effectiveness of 12 herbicides in controlling hairy fleabane [ Conyza bonariensis (L.) Cronquist] in a date palm orchard located in the central Jordan valley during the spring of 2017. Results showed that C. bonariensis resists paraquat (2.5, 5 and 7.5kgha -1 ), oxadiazon (5kgha -1 ) and oxyflourfen (3.3kgha -1 ) herbicides applied at normal or higher than the recommended rates. None of the three herbicides was significantly effective against the weed and treated plants continued growing normally similar to those of untreated control. Higher rates (10-fold of the recommended rates) of the same herbicides failed to control the weed. The effect of other tested herbicides on the weed was varied with bromoxynil plus MCPA (buctril ® M), 2,4-D- iso-octyl ester, glyphosate, glyphosate trimesium and triclopyr were most effective and completely controlled the weed at recommended rates of application. Testing paraquat, oxadiazon and oxyflourfen using the normal recommended and 10-fold higher rates on two populations of C. bonariensis grown from seeds of the date palm and al-Twal (another site in the Jordan Valley) weed populations and grown in pots under glasshouse conditions showed that Date palm population was resistant to the three herbicides at both application rates while al-Twal site population was highly susceptible and completely controlled at normal and high rates of the three herbicides. It is concluded that certain populations of C . bonariensis developed resistance to paraquat, oxadiazon and oxyflourfen but control of this weed was possible using other herbicides of different mechanism of action. Herbicide rotation or other nonchemical weed control methods have been suggested to prevent or reduce the buildup and spread of resistant populations of this weed species. These results represent the first report on herbicide resistance of C. bonariensis in Jordan.

The Effect of Polyamines and Silver Thiosulphate on Micropropagation of Date Palm Followed by Genetic Stability Assessment

There are some limitations in the practical applications of in vitro date palm tissue culture, such as low multiplication efficiency, low rooting rate, and high mortality experienced by in vitro raised plantlets during laboratory to soil transfer. This study’s objective was to investigate the effect of the two types of polyamines (putrescine "PUT" and spermidine" SPD") in combination with silver thiosulfate (STS) on the growth and development and genetic stability of cultures of Quntar cultivar. Media supplemented with 75 mg L−1 SPD in combination with 10 mgL−1 STS gave the highest percentage of callus producing buds (83.34%) and average bud formation (16.3) per jar. The addition of PUT and STS to the medium was most effective in root formation and the number of roots per shoot, where the best result 91.67% and 6.37 roots per shoot, respectively, were obtained using 75 mgL−1 PUT and 10 mgL−1 STS, resulting in fast-growing plantlets during acclimatization phase, reaching 90% of plant survival. The genetic fidelity assessment of plants derived from micropropagation was confirmed by RAPD analysis. Four operon primers were used, and all of them showed amplified unambiguous (OPA02, OPC-04, OPD-07, and OPE-15). All generated bands were monomorphic and had no variation among the tissue culture-derived plants tested. Accordingly, these results indicate that adding polyamines and silver thiosulfate to the nutrient medium of date palm cv. Quntar is beneficial in improving shoot organogenesis, rooting, and production of genetically stable date palm plants.

The Efficiency of Long Primers Compared to The Short Primer for RAPD Technique in Date Palm

Random Amplified Polymorphic DNA (RAPD) applies single arbitrary short primers (8-12nucleotides) to produce many amplified discrete DNA. Limited reports and studies were done onthe use of long primers (over 12 bases). This study was performed to investigate the potential valueof long primers (15-21 bases) for generating RAPD polymorphisms. We compared both short andlong primers in RAPD assays of two date palm cultivars grown in Malaysia: Ajwa and Barhi. Thenumber of produced polymorphic fragments ranged in order from 2 and 38 bands for short andlong primers in Ajwa. Meanwhile, more polymorphic fragments were generated by long primersin Barhi, which were 50 and only five bands for short primers. 18-mer GY107 and 20-mer CO4primers yielded 100% polymorphism in Ajwa and Barhi, respectively. Moreover, long primersproduced more DNA fragments and a wider range of DNA fragment sizes (from 140-1600 bp,with respect to 300-1000 bp obtained with 10-mer primers). Hence, a significant correlation wasobserved between primer length and the number of polymorphic fragments within the long primergroup, suggesting that increasing primer length above 15 bases may demonstrate enhancedproduction of more polymorphism.

Management of Deleterious Effect of Fusarium oxysporum Associated with Red Palm Weevil Infestation of Date Palm Trees

Red palm weevil (RPW) is a dangerous pest that infects the date palm tree and makes tunnels in the tree’s trunk. RPW infection is followed by secondary invaders of microorganisms that cause degradation of the trunk tissues leading to toppling the crown and death of the tree in a short time. This study showed that Fusarium oxysporum Schlecht. was the common fungal species isolated from the root and trunk tissues of the date trees infested with RPW, which recorded 100% of frequency. Pathogenicity of 4 isolates of F. oxysporum was confirmed on date palm seeds and seedlings. The results confirmed that all isolates involved in rot of the germinated seeds (40–100% incidence), root rot, and death of palm seedlings (20–100%) under artificial infection as well as degradation of date palm petioles. Application of 20 L/palm of systemic fungicide (Topsin) at 1% as foliar and soil drench of date palm for successive three times successfully reduced development of the deterioration and suppressed the growth of F. oxysporum. Interestingly this fungicide did not suppress the growth of Trichoderma viride Pers. So, our results recommend this fungicide to suppress the pathological and degradable activities of F. oxysporum during the integrated pest management of RPW on date palm trees.

Physical and mechanical properties of mortars containing date palm fibers

This paper presents the results of a study conducted to investigate the effects of incorporating Sefri Date Palm Leave Fibers (SDPLF) into the mortar. A total of seven mixtures were prepared and tested. SDPLF were collected from local farms. The fibers were then cleaned, dried, and cut to different sizes of 10 mm, 20 mm, and 50 mm, maintaining the same individual fiber width of approximately 5±2 mm. The content of SDPLF in mortars was kept to 1% and 3% by mass. The physical and mechanical properties of SDPLF fibers and SDPLF mortars were investigated. The compressive strength at 7, 14, and 28 days was determined. The water absorption rate test was carried out on mortars containing 1% SDPLF fibers. The results showed that mortars with SDPLF have lower workability, lower density, and lower compressive strength as compared to control mortars. However, they are still acceptable for use in construction works. Mortars containing 10 mm and 20 mm SDPLF fibers by mass showed significant improvement in terms of water absorption rate as compared to the control mortar.