J.R. Qasem

• PhD
• Professor (Full) at University of Jordan

The effect of paraquat, oxadiazon and oxyfluorfen herbicides was tested on two populations of hairy fleabane (Erigeron bonariensis L.), collected from a date palm orchard at Tal al-Ramil (Central Jordan Valley) and al-Twal (Northern Jordan Valley) sites using the recommended rates (0.5, 1.25 and 0.792kg a.i ha⁻¹ for each herbicide, respectively) an...

A field demonstration and pot experiments were implemented to assess the effect of paraquat, oxadiazon, and oxyfluorfen herbicides in controlling selected populations of fleabane Conyza bonariensis (L.), grown in the central valley of Jordan. Conyza mature seeds were collected from six investigated sites (five from Jordan valley named P1, P2, P3, P...

A field demonstration and pot experiments were implemented to assess the effect of paraquat, oxadiazon, and oxyfluorfen herbicides in controlling selected populations of fleabane Conyza bonariensis (L.), grown in the central valley of Jordan. Conyza mature seeds were collected from six investigated sites (five from Jordan valley named P1, P2, P3, P...

Ultrasound technology has been recently used to enhance and increase seed germinationwith no negative effect on seedling development. This study investigated the effects of ultrasoundexposure for 10, 20, and 30 min on seed germination, seedling growth, and gene expression of threesoybean varieties grown under glasshouse conditions. Ultrasonic treat...

Ultrasound technology has been recently used to enhance and increase seed germination with no negative effect on seedling development. This study investigated the effects of ultrasound exposure for 10, 20, and 30 min., on seed germination, seedling growth, and gene expression of three soybean varieties grown under glasshouse conditions. Ultrasonic...

Epigenetic variations are inherited or uninherited effects that occur beyond the DNA sequence of an individual. However, DNA sequence has a critical role in shaping epigenetic variation. The great diversity of epigenetic markers confers an advantage of various uses without interrupting its highly environmental independence. The epigenetic effects a...

This book introduces the most recent research findings on selected parasitic weeds that occur in Jordan and are also spread in Middle Eastern countries. It is a valuable source of information for researchers, students as well as farmers, giving readers a better understanding of these regional parasites and their unusual growth patterns. The book se...

This book introduces the most recent research findings on selected parasitic weeds that occur in Jordan and are also spread in Middle Eastern countries. It is a valuable source of information for researchers, students as well as farmers, giving readers a better understanding of these regional parasites and their unusual growth patterns. The book se...

This book introduces the most recent research findings on selected parasitic weeds that occur in Jordan and are also spread in Middle Eastern countries. It is a valuable source of information for researchers, students as well as farmers, giving readers a better understanding of these regional parasites and their unusual growth patterns. The book se...

This book introduces the most recent research findings on selected parasitic weeds that occur in Jordan and are also spread in Middle Eastern countries. It is a valuable source of information for researchers, students as well as farmers, giving readers a better understanding of these regional parasites and their unusual growth patterns. The book se...

This book introduces the most recent research findings on selected parasitic weeds that occur in Jordan and are also spread in Middle Eastern countries. It is a valuable source of information for researchers, students as well as farmers, giving readers a better understanding of these regional parasites and their unusual growth patterns. The book se...

This book introduces the most recent research findings on selected parasitic weeds that occur in Jordan and are also spread in Middle Eastern countries. It is a valuable source of information for researchers, students as well as farmers, giving readers a better understanding of these regional parasites and their unusual growth patterns. The book se...

This book introduces the most recent research findings on selected parasitic weeds that occur in Jordan and are also spread in Middle Eastern countries. It is a valuable source of information for researchers, students as well as farmers, giving readers a better understanding of these regional parasites and their unusual growth patterns. The book se...

This book introduces the most recent research findings on selected parasitic weeds that occur in Jordan and are also spread in Middle Eastern countries. It is a valuable source of information for researchers, students as well as farmers, giving readers a better understanding of these regional parasites and their unusual growth patterns. The book se...

This book introduces the most recent research findings on selected parasitic weeds that occur in Jordan and are also spread in Middle Eastern countries. It is a valuable source of information for researchers, students as well as farmers, giving readers a better understanding of these regional parasites and their unusual growth patterns. The book se...

This book introduces the most recent research findings on selected parasitic weeds that occur in Jordan and are also spread in Middle Eastern countries. It is a valuable source of information for researchers, students as well as farmers, giving readers a better understanding of these regional parasites and their unusual growth patterns. The book se...

This book introduces the most recent research findings on selected parasitic weeds that occur in Jordan and are also spread in Middle Eastern countries. It is a valuable source of information for researchers, students as well as farmers, giving readers a better understanding of these regional parasites and their unusual growth patterns. The book se...

Parasitic weeds of Jordan, species, hosts, distibution and management

This study was conducted to survey and characterize wild populations of date palm in Jordan. Phenotypic parameters either vegetative, leaf morphology, physical and chemical properties of fruits, and genetic diversity within and among populations were also, analyzed. Ecogeographical survey showed that date palm trees are naturally growing in differe...

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 oxyflour...

Broomrapes (Orobanche spp.) are among the most damaging parasitic weeds to agriculture. They subsit themselves on the root systems of a wide range of cultivated and wild grown plant species of different plant families. These parasites are varied in morphology and hosts they attack although share a large number of host species. Certain Orobanche spe...

Wheat is the main field crop grown in Jordan. Productivity is low due to different factors, including erratic rainfall, poor soil fertility and weed competition. A field experiment was carried out at the University of Jordan Research Station for two growing seasons to determine the effect of weed competition on growth and yield of wheat (Triticum d...

Six field experiments were conducted at Al-Muwaqar (arid) and Al-Jubeiha (Mediterranean) locations, Jordan for four years to study establishment, growth and production of selected medicinal species under supplimentary irrigation, water harvesting and soil conditioner treatments. Results showed that 70% of plot area left for water harvesting signifi...

Aqueous fresh shoot extracts of 200 plant species from 47 plant families were evaluated for their herbicidal activities on Amaranthus retroflexus L. and Chenopodium murale L. Foliar applications of 192 extracts reduced shoot dry weight and height of A. retroflexus and all extracts reduced both growth parameters of C. murale under glasshouse conditi...

Effects of olive cake and olive mill waste water on Orobanche ramosa L. infection to tomato (Lycopersicon esculentum Mill.) were investigated in pot experiments conducted under glasshouse conditions during the spring/summer seasons of the 2016 and 2017. Treatments included the use of olive mill cake, cake extracts or mill waste water. In all experi...

Field experiments were carried out to evaluate the effects of different soil mulch materials and herbicides on growth and yield of tomato and weed control at two locations in Jordan during the 2016 and 2017 growing seasons. Treatments included different new nonwoven biodegradable UV-treated polypropylene fabrics, paper, black plastic, animal manure...

Solanum elaeagnifolium (silverleaf nightshade) is a problematic weed that is common in Jordan and difficult to control. The weed exhibits distinct morphological variations in growth habit, leaf shape, leaf margins, flower colour and presence or absence of spines between individuals among and within populations suggesting genetic differences. Geneti...

Forty-four plant species of 13 families were tested as trap plants reducing Orobanche ramosa L. infestation on tomato under glasshouse conditions. Many species were parasitized but Orobanche shoot number and dry weight were varied. Petroselinum sativum Hoffm and Trifolium alexandrinum L. were the most infested and Origanum syriacum L. and Citrull...

Although all tested extracts have the ability to promote plant growth, such an ability is extract-dependent but volume-independent. The increase in plant growth, as mediated by some extracts, ranged between two- to threefold on treated plants when compared to control plants..

Exploring the plant growth promotion effect of several plant extracts

Phytotoxic effects of some vegetable crops including bean, cabbage, cauliflower, eggplant, pepper, potato, radish and tomato were investigated against Amaranthus retroflexus, Chenopodium murale, Eruca sativa, Malva sylvestris, Portulaca oleracea and Solanum nigrum weed species under laboratory and glasshouse conditions. Shoot extracts, foliage leac...

The effects of individual and combined application of endophytic fungal entomopathogens (Beauveria bassiana strain NATURALIS and Metarhizium brunneum strain BIPESCO5) and aqueous extracts of two medicinal plants (Calotropis procera and Inula viscosa) on the survival and development of the sweetpotato whitefly (Bemisia tabaci) were investigated for...

Competition of 31 tomato (Lycopersicon esculentum Mill) cultivars with Amaranthus retroflexus and Chenopodium murale was investigated at different growing periods under natural conditions, University of Jordan, during 2008–2010. Cultivars were varied in their competitiveness with weeds; some tolerated while others were highly susceptible and exhibi...

The effects of individual and combined application of endophytic fungal entomopathogens (Beauveria bassiana strain NATURALIS and Metarhizium brunneum strain BIPESCO5) and aqueous extracts of two medicinal plants (Calotropis procera and Inula viscosa) on the survival and development of the sweetpotato whitefly (Bemisia tabaci) were investigated for...

In Laboratotry bioassays, the extracts of 136 plant species (40 families) in Jordan were collected and investigated for their phytotoxicities on wheat (Triticum durum L. cv. Stork). All aqueous extracts reduced the wheat seed germination and shoot (except Smilax aspera L.) and root growth (except Launaea nudicaulis (L.) Hook.) than control. There w...

Desert Hyacintyh (Cistanche spp.) By Professor Jamal Ragheb Qasem Faculty of Agriculture, University of Jordan Cistanche spp. Are annual or perennial root holo-parasitic plants that attack different plat species in arid and semi-arid land and distributed in tropical and sub-tropical regions in different parts of the world. Although different specie...

A new technology is developed to separate allelopathy from competition in pot experiments. Square pots of any sizes may be used. Each pot is divided by a metal or pvc mesh (100-150 micrometer) barrier fi xed from the bottom to pot surface. The barrier divides the pot into two sections fi lled by the same amount of soil mixture. Seeds or seedlings o...

In field conditions, Anthemis cotula L. forms pure stands excluding the wheat, barley and replacing Hordeum spontaneum (K. Koch) Thell weed. Laboratory and glasshouse experiments were done to investigate the possible allelopathic inhibitory effects of this weed on wheat and barley. High concentrations of fresh shoot extracts inhibited the seed germ...

A field survey of wild medicinal and industrial plant species in saline habitats in the area extended along 75 km in the Jordan Valley was carried out during 2010. Results showed occurrence of 263 species of 59 62 plant families in the region. The highest numbers were belonging to Compositae (48 species), Gramineae (18 species) and Chenopodiaceae (...

This study was conducted to survey and characterize wild populations of date palm in Jordan. Phenotypic parameters either vegetative, leaf morphology, physical and chemical properties of fruits, and genetic diversity within and among populations were also, analyzed. Ecogeographical survey showed that date palm trees are naturally growing in differe...

A field survey was conducted to assess the occurrence of Solanum elaeagnifolium Cav. in the Jordan Valley during 2011 and 2012. S. elaeagnifolium was found in field crops, on roadsides, on fallow land, in pastures, and around water sources. Different vegetable and fruit tree crops were infested and had suffered from this invasive weed species throu...

Allelopathic phenomenon perpetuating in nature is of considerable significance, which has gained even more importance these days. Field applications of allelopathy have attracted the attention of scientists as an alternate to weedicide use. In this chapter, allelopathy development and its application for weed management have been reviewed over the...

The antifungal effects of scarlet pimpernel (Anagallis arvensis L.) extract or dried materials on wheat leaf spot (Helminthosporium sativum King & Bakke) and tomato wilt (Fusarium oxysporum Schlecht) fungi were investigated using different experimental techniques under laboratory conditions. Results showed that shoot and root extracts or dried mate...

Matthiola arabica is an annual weed widely spread in arid and semi-arid regions in Jordan. It forms colonies in wheat fields at which crop plants were almost absent suggesting an allelopathic activity. Therefore, possible inhibitory effect of this species was investigated through different laboratory and glasshouse experiments. Results showed that...

Allelopathy techniques usually used under field conditions, may help in understanding and identifying allelopathic species and their harmful influences on other species are presented and discussed. New suggested technology enables the students and researchers to better understand the allelopathy mechanism in field are also included and explained. S...

A field survey was carried out to record plant species climbed by Ephedra alte in certain parts of Jordan during 2008–2010. Forty species of shrubs, ornamental, fruit, and forest trees belonging to 24 plant families suffered from the climbing habit of E. alte. Growth of host plants was adversely affected by E. alte growth that extended over their v...

The antifungal effects of scarlet pimpernel (Anagallis arvensis L.) extract or dried materials on wheat leaf spot (Helminthosporium sativum King & Bakke) and tomato wilt (Fusarium oxysporum Schlecht) fungi were investigated using different experimental techniques under laboratory conditions. Results showed that shoot and root extracts or dried mate...

Parasitic weed occurrence in Jordan was surveyed during the period from 2004 to 2009. Results revealed the presence of seven genera attacking 85 woody plant species belong to 33 botanical families. Parasitic genera were Cuscuta, Orobanche, Cistanche, Plicosepalus, Viscum, Osyris and Cynomorium. Among the most severely parasitized species were Citru...

This chapter deals with negative effects of weeds on wheat crop, the impact of weed competition on quantity and quality of wheat yield, allelopathic effects of certain weeds on crop growth and development and the poison effect of other weed species to humans and animals. Weeds usually found in wheat fields and associate with crop plants were identi...

Growth and competitive abilities of cauliflower (Brassica oleracea L. var. botrytis cv. ‘White Cloud’) and nettle-leaved goosefoot (Chenopodium murale L.) were investigated under glasshouse conditions. The two species responded differently to a reduction in potassium (K) levels in the medium. Growth of C. murale was reduced while that of cauliflowe...

Allelopathic activity of some common weed species in onion fields in Yemen Republic was investigated under laboratory and growth chamber. Test weeds spp. were: Amaranthus graecizans L., Alhagi maurorum Medik., Brachiaria reptans L. Gard. & Hubb., Cassia italica (Mill) Lam. Ex. Steus., Corchorus trilocularis L., Cyperus rotundus L., Dactyloctenium a...

The effects of water stress and planting density on the competitive relationships, yield performance, and dynamics in canopy dominance of cowpea [Vigna sinensis (L.) Savi ex Hassk] and redroot pigweed (Amaranthus retroflexus L.) grown in pure and mixed stands were investigated under glasshouse and field conditions. Results showed that water stress...

The effects of Malva sylvestris and Sisymbrium irio on wheat and barley were used to model the differences in the observed effects of plant species in the field, laboratory and glasshouse experiments. Observations on the effects of two weed species on same crops in field differed from their effects under laboratory or glasshouse conditions. The dif...

Field experiments were conducted to study the effects of oxadiazon and oxyfluorfen on weeds and Syrian marjoram (Origanum syriacum L.) in the central Jordan Valley during the period from 1998 to 2001. Results showed that weed competition with marjoram for the whole growing period resulted in almost complete crop failure. Oxyfluorfen and oxadiazon a...

A botanical survey conducted from 2003 to 2007 showed the occurrence of the acacia strap flower and the Oriental mistletoe plant in different regions in Jordan. Acacia strap flower was found parasitizing 26 plant species belonging to 12 families. Oriental mistletoe attacked 14 plant species from eight families. Parasitized species ranged from wild...

A field experiment was carried out in 1996/1997 and repeated in 1997/1998 at the Jordan University Research Station located in the central Jordan Valley to determine the effect of weed competition on growth and yield of cauliflower Brassica oleracea var. botrytis cv. “White Cloud”. The treatments consisted of either allowing weeds to infest the cro...

A field survey of the Orobanchaceae family members and their hosts in Jordan was carried out from 2003 to 2007. The intensity of parasite infection on different hosts and the severity of the infestation were evaluated. The results showed the presence of seven species of Orobanche and three species of Cistanche. The Orobanche species were found para...

The importance, characteristics, positive and negative impacts, and future role of weeds as an integral part of the natural and agroecosystems are evaluated and discussed. Interference between plants in nature and the importance of differentiating between competition and allelopathy are interpreted. Allelopathy as one component of weed/crop interfe...

Aqueous extract effects of 64 weed species on growth and development of AlIernaria solani Sorauer, Helminthosporium sativum King & Bakke and Rhizoctonia solani Kuhn, plant pathogenic fungi were studied in vitro. Extracts varied in the strength and persistence of their antifungal effects against the three fungi species. Some stimulated, others inhib...

The effects of aqueous extracts of some common weed species against Fusarium oxysporum Schlecht f.sp. lycopersici (the causal agent of tomato wilt disease) were investigated under laboratory conditions. Anagallis foemina L., Cerastium dicotomum L., Falcaria vulgaris L., Ranunculus asiaticus L., Scorpiurus mur-icatus L. and Solanum nigrum L. extract...

Studies on the host range of Orobanche ramosa L., by screening different Summer and Winter crops, medicinal herbs, and a large number of weeds for possible attack by the parasite, revealed substantial variation among species in the number and vigour of parasites attached to their roots. The crops and medicinal herbs most affected were: Apiwn graveo...

The competitive relationship, yield performance, and dynamics of canopy dominance of cowpea [Vigna sinensis (L.) Savi ex Hassk.] and redroot pigweed {Amaranthus retroflexus L.) grown at different levels of phosphorus (P), planting densities, and density proportions, were studied under field conditions in Summer 2001. Both species behaved differentl...

Field experiments were conducted for 2 years to evaluate the effectiveness of certain herbicides on wild-oat (Avena sterilis L.) in wheat (Triticum durum L.). Results showed that tralkoxydim (0.3la.i.ha−1), imazamethabenz-methyl (0.5 and 0.63la.i.ha−1) and the mixture of imazmethabenz-methyl (0.38la.i.ha−1) and isoproturon (0.5la.i.ha−1) increased...

Field experiments were carried out to evaluate the effect of different herbicides on weeds and cauliflower (Brassica oleracea var. Botrytis cv. White Cloud) grown under Jordan Valley conditions during the 1996/1997 and 1997/1998 growing seasons. The most common weed species were Chenopodium murale L. (133plantsm−2), Malva sylvestris L. (38plantsm−2...

Syrian mesquite, Prosopis farcta (Banks and Sol.) Macbride, is a nuisance, rhizomatous perennial weed dominating an important part of productive agricultural land in the Jordan Valley. It tolerates traditional methods of weed control such as soil solarization and mechanical methods. Two field experiments were carried out to evaluate the effect of d...