Nezar Samarah

• PhD
• Professor at Jordan University of Science and Technology

Drying wheat (Triticum durum) seeds within their spikes may improve the seed desiccation tolerance. This study aimed to understand the effect of drying wheat seeds within their spikes on their desiccation tolerance in association with GABA (γ-aminobutyric acid) content, malondialdehyde (MDA), the expression of three dehydrin genes (dhn, wcor, dreb)...

Since freshwater water resources are depleting, reclaimed treated water (RW) is used as an alternative source for irrigation. Two experiments were conducted under field conditions to evaluate the effects of using reclaimed water on pollen productivity, insect flower visitation, flower number, and fruit yield and quality of species of Cucurbitaceae....

High salinity leads to a reduction in growth, germination, metabolic stability, and production of pepper (Capsicum annuum L.) plants worldwide. GABA priming showed a positive effect on plant growth and development and improved plant stress tolerance. The current study aimed to investigate the effect of exogenous GABA treatments on endogenous GABA s...

Grain yield of wheat is primarily limited by water stress. Therefore, to increase productivity under drought conditions, a pot experiment was carried out at Maru Agricultural Research Station (MARS), Jordan, during the year 2021 to investigate the effect of foliar fertilizer by boron and magnesium under drought at either tillering or anthesis stag...

Salinity stress inhibits seed germination of lettuce ( Lactuca sativa L.) due to osmotic stress and ion toxicity. Therefore, the objective of this study is to understand how salinity reduces seed germination of two lettuce cultivars, ‘Susan’ (the high salt-sensitive cultivar) and ‘Yafa’ (the low salt-sensitive cultivar), in relationship with the en...

A pot experiment was carried out to investigate the impact of seed priming on some physiological parameters, growth, and yield components of four durum wheat varieties (Hourani, Umqais, Sham 1, and Maru 1) during both stages of tillering and anthesis drought. Four pre-sowing seed treatments (hydropriming with distilled water, osmopriming with PEG,...

Grain yield of wheat is primarily limited by water stress. Therefore, to increase productivity under drought conditions, a pot experiment was carried out at Maru Agricultural Research Station (MARS), Jordan, during the year 2021 to investigate the effect of foliar fertilizer by boron and magnesium under drought at either tillering or anthesis stage...

Polymer coating of zucchini seeds is a method to enhance seed performance during germination and emergence in the field and protect the seed from infection with diseases and insects. Experiments were conducted to identify the best method for polymer coating squash seed to improve seed germination and performance. In the first experiment, seeds were...

Treatments of wheat (Triticum durum L.) seeds with sonication or hydropriming may enhance seed germination and vigour in association with γ-aminobutyric acid (GABA). Therefore, the objective of this study is to examine the effect of sonication and hydropriming treatments on seed germination of wheat through the characterisation of seed germination...

Activation of γ-aminobutyric acid (GABA) shunt pathway and upregulation of dehydrins are involved in metabolic homeostasis and protective mechanisms against drought stress. Seed germination percentage, seedling growth, levels of GABA, alanine, glutamate, malondialdehyde (MDA), and the expression of glutamate decarboxylase (GAD) and dehydrin (dhn an...

Salinity is an abiotic stress that reduces the seed germination and productivity of tomatoes. Magnetic treatment has been shown to have a positive effect on the seed germination, seedling growth, and productivity of various crop species. Therefore, three experiments were conducted to evaluate whether treating saline water or seeds with a magnetic f...

Tomato brown rugose fruit virus (ToBRFV), belonging to the genus Tobamovirus, is a highly virulent emerging virus, causing disease outbreaks and significant crop losses worldwide. The growing number of ToBRFV epidemic episodes prompted the investigation of the role of seeds in the dissemination of the virus as an important aspect in the overall dis...

Salinity is one of the main factors in reducing crop output due to poor plant growth. According to scientists, salinity affect the growth of crops in two ways: through the osmotic effect, which reduces the plants’ ability to absorb water and retard growth; and through ionic toxicity, which means that salts can enter the perspiration system and dama...

The high grain yield of wheat is limited by the dominance of weeds, particularly wild oat. Therefore, to improve wheat yield under these conditions, a field experiment was carried out in Maru Agricultural Research Station, Jordan during 2015–2016 and 2016–2017 to investigate yield response of two wheat varieties (Triticum durum L.) to different til...

This study was conducted to examine the effect of storage temperature and duration on viability and in vitro germination of pollen grains of seven pistachio cultivars. Pollens were stored at room temperature (24 o C±2), refrigerator (4 o C) and freezer (-5 o C) for 0, 1, 2, 3 and 4 weeks. Pollen viability was estimated by using staining methods inc...

Tomato brown rugose fruit virus (ToBRFV), belonging to the genus Tobamovirus, is a highly-virulent emerging virus species, causing disease outbreaks and significant crop losses worldwide. No effective measure has been identified to control ToBRFV infection. Therefore, the objectives of this study were to investigate the effectiveness of three seed...

The high demand of barley for animal feed and the scarcity of fresh water increase the need for the reuse of treated wastewater as an alternative source for irrigation. Therefore, two-field experiments were conducted to study physiological processes, plant growth, grain yield and yield components of four-barley cultivars grown under four-irrigation...

The developmental stage of durum wheat (Triticum durum) may affect seed germination and seed damage by lesser grain borer, Rhyzopertha dominica F. (Coleoptera: Bostrichidae), which is considered a major pest damaging the quality of the stored seeds in Jordan. The objective of this experiment was to evaluate the effect of the developmental stage of...

Fast germination and vigorous early seedling growth are essential for establishment of pepper (Capsicum annuum), a warm season crop that germinates poorly under cold conditions. Three experiments compared effects of seed treatments on ‘California Wonder’ bell pepper seed germination percentage, mean time to germination (MTG), seedling emergence in...

Thermogradient tables were first developed in the 1950s primarily to test seed germination over a range of temperatures simultaneously without using a series of incubators. A temperature gradient is passively established across the surface of the table between the heated and cooled ends and is lost quickly at distances above the surface. Since temp...

Depending on duration and severity, drought stress causes many morphological, physiological, biochemical, and molecular changes in plants. At the morphological level, drought in general, reduces leaf expansion and growth and results in smaller plant size, lower leaf area index, and lower plant biomass and yield. The consequence of the drought stres...

Seed desiccation tolerance is acquired late during seed development to enable the seeds to maintain their germination capability after drying down to low moisture content. The objective of the research was to study the relationship between seed desiccation tolerance and the evolution of ethylene from the podded and depodded seeds of soybean during...

The objective of the present study was to determine the activity of antioxidant enzymes: superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) and the expression of their genes in two barley genotypes under controlled severe drought. To fulfill this objective, 21-day-old barley plants of two genotypes: Rum and Yarmouk were expo...

Drought is a major abiotic stress that restricts growth and productivity of many crops. The objectives of this study were to assess the morphological and physiological responses of barley plants at the vegetative stage to controlled severe drought, and to test the expression of drought-responsive genes (HvHsdr4, HvNCED2, HvDHN1, HvDHN9, and HvCBF3)...

Polymer coating of squash seeds (Cucubita pepo Zucchini) is an important method to enhance the seed performance during germination and emergence in the field and protect the seeds from infection with diseases and insects. Two experiments were conducted to identify the best method for polymer coating of squash seeds to improve seed germination and p...

Leucaena leucocephala and Acacia farnesiana are tree species used for several agricultural purposes in the Mediterranean region. The seeds of these species exhibit dormancy, causing delayed germination. Two experiments were conducted to investigate the effect of pre-sowing treatments (scarification, hot water, or soaking) on seed germination of L....

Impact of different irrigation levels on the melon fruit characteristics, total fruit yield and water use efficiency (WUE) was studied under field conditions in arid region. Two experiments with three treatment levels of actual evapotranspiration (AET) were tested. These treatments were: 0.50 AET (T1), 0.75 AET (T2) and 1.00 AET (T3). Irrigation le...

Chickpea grown in the semiarid Mediterranean environments of West Asia and North Africa may experience an extended late-drought stress. The objective of this experiment was to evaluate seed dry weight accumulation, reproductive growth duration, and seed yield in five chickpea genotypes in order to identify those under drought stress. Chickpea plant...

This experiment was carried out during the growing season 2005 at the campus of Jordan University of Science and Technology (32°22” N, 35°49” E), Jordan. Two different Nigella species were used in this experiment; Nigella sativa L. and Nigella damascena L. This study was aimed to identify the bee visitors of Nigella species and the pollination requ...

Late-terminal drought stress during grain filling has recently become more common in the semi-arid Mediterranean region, where barley (Hordeum vulgare L.) is grown as an important winter cereal crop. Little information is available in the literature about the effect of late-terminal drought stress on seed germination and vigor of barley. The object...

The effect of drought stress on crop growth and yield has become more common worldwide in the last two decades. The reproductive stage is the most critical stage for drought stress during crop growth, because it strongly impacts yield and seed quality. Improving crop growth and yield under drought is thus a major goal of plant breeding. Drought str...

Two-year field experiments were conducted to study the effect of two planting dates and seed maturity on mineral content of chickpea seeds. In 2003 and 2004, chickpea 'Jubiha-2' seeds were planted in late December (winter-sown) and early March (spring-sown). For both planting dates, pods were harvested at five maturity stages: 1) beginning of seed...

Two field experiments were conducted to study the effects of seed maturity and four drying treatments on seed desiccation tolerance and vigour of wheat during maturation. Spikes of wheat grown during the 2005/6 and 2006/7 seasons were hand harvested at five seed development stages: milk-stage (ML), soft-dough stage (SD), hard-dough stage (HD), phys...

A laboratory experiment was conducted to determine the effect of ultrasound (US) treatment on seed germination of chickpea, wheat, pepper and watermelon. All tests were carried out at 40 kHz in a water bath ultrasonic device varying two factors, treatment duration (5, 10, 15, 30,45 or 60 min) and germination temperature (15 or 20 degrees C). Parall...

A field experiment was conducted during 2005/2006 at Jordan University of Science and Technology campus (32°30” N, 35°59” E), Irbid, Jordan, to study the role of bee visitors on seed set and production of Vicia villosa spp. dasycarpa grown under semiarid conditions. Two treatments were imposed on Vicia villosa plants before flowering: 1) Plants wer...

Barley (Hordeum vulgare L.) is an important winter cereal crop grown in the semiarid Mediterranean, where late-terminal drought stress during grain filling has recently become more common. The objectives of this study were to investigate the growth performance and grain yield of four barley cultivars under late-terminal drought stress under both gl...

A 2-year field study was conducted during the rainy seasons of 1999 and 2000 at Houfa in northern Jordan, to study the influence of various sowing rates (20kg ha-1, 40kg ha-1 and 60kg ha-1) and 2,4-D application at two growth stages (stage 13 (3-leaf) and stage 44 (Mid boot)) on yield components and productivity of wild oats. The highest biomass an...

Agroforestry is a leading alternative for food security and forest conservation. A full understanding of positive and negative, i.e. allelopathic, interactions between crops and forest trees is necessary for producing crops and conserving forests especially within the threatened Mediterranean forest ecosystems. The present study explored the allelo...

Common vetch seeds are desiccation intolerant when seeds are harvested at immature stages of development and extracted from pods before drying. Drying the immature seeds in intact pods improved desiccation tolerance in association with slow drying rate; however, an index to quantify the rate of seed moisture loss has not been studied. Therefore, th...

The effect of drying seeds inside intact pods and drying temperatures on seed vigour of soybean during maturation has not been documented in the literature. The objective of this experiment was to study the effect of drying temperatures, seed maturity, and pod integrity on soybean seed germination and vigour as estimated by accelerated aging test (...

An experiment was conducted to examine the importance of honeybees and flowering dates for pollination and pod characteristics of Prosopis juliflora grown under semiarid conditions. Flowers of Prosopis were subjected to two pollination treatments: 1) open pollination and 2) supplementary pollination at different flowering dates from September to Ja...

A greenhouse experiment was conducted to study the effect of drought stress on seed germination and vigor of soybean in relation with soluble sugars. Three drought stress treatments, well-watered treatment (WW), gradual stress (GS) imposed prior to severe stress treatment, and sudden severe stress (SS), were imposed on soybean plants at beginning s...

This study was initiated to determine the effect of different treatments on breaking dormancy and enhancing germination of black iris seeds in vivo and in vitro. Mature seeds were leached and the outer integument was clipped. The seeds were then treated with different concentrations of GA3, thiourea, or KNO3. Immature seeds and leached-clipped matu...

Common vetch (Vicia sativa L.) is an important legume cultivated for feed grain and forage in the Mediterranean and Central Asia regions. Little information is available about the changes in seed mass, chemical composition, and mineral concentration in the developing seeds of common vetch. Therefore, the objective of this experiment was to study th...

The effects of two sowing dates (winter and spring) and five seed maturity stages on the germination and the vigour of chickpea (Cicer arietinum) seeds were determined. In 2003 and 2004, seeds of chickpea cultivar "Jubiha-2" were planted in late December (winter-sown) and early March (spring-sown) and plants were harvested at five pod maturity stag...

Standard germination and vigor tests can be used to predict field emergence of aged barley seeds. The objective of this experiment was to study the effect of aging on seed quality of barley and to identify the best seed quality test to predict field performance of aged barley seeds in the semiarid Mediterranean region in Jordan. Seeds of two barley...

Drying common vetch seeds in the intact pods improved their desiccation tolerance and germination, this may be due to a slower rate of seed moisture loss or additional gain of dry weight of the seeds. Little information is available on the effect of slow drying on the desiccation tolerance of immature seeds of common vetch. The objective of this ex...

Wheat (Triticum durum L.) is considered one of the most widely grown cereal crops under rainfed conditions in Jordan. The traditional or conventional tillage systems practiced in Jordan depleted soil resources and resulted in lower crop yields. Therefore, the conservation tillage system is expected to increase crop yield as compared with the tradit...

There is no information on accumulation of dehydrin proteins during seed development and maturation of soybean [Glycine max (L.) Merr.] in response to drought stress. Our objective was to study accumulation of dehydrin-like proteins in developing soybean seeds in response to drought stress. A greenhouse experiment and a field experiment were conduc...

Immature seeds of common vetch had low germination and were desiccation sensitive when seeds were extracted from pods before drying. Air‐drying immature seeds in harvested pods may improve their germination and vigour. The objective of this experiment was to study the effect of air‐drying immature seeds in harvested pods on seed germination and vig...

Planting date may affect barley grown in semi-arid regions, where high temperature and drought stress are common during late crop development and maturation. The objective of this research was to study the effect of planting date on seedling emergence, yield and yield components, seed germination and vigor of two barley cultivars. Field emergence,...

Little information is available about the change in total soluble and dehydrin-like proteins in shriveled seeds produced under drought stress. A greenhouse experiment was conducted to study the accumulation of total soluble, heat-stable and dehydrin-like proteins in full-rounded and shriveled seeds produced under drought stress. Three drought stres...

Common vetch seeds acquire the germination capability at specific developmental stage. Post-harvest seed drying may affect seed desiccation tolerance and seed germination and dormancy. A field experiment was conducted to study the effect of drying methods on seed germination and dormancy of common vetch harvested at different maturity stages. Plant...

This study was conducted to improve the seed germination of Oldman saltbush (Atriplex nummularia), which is an important fodder shrub commonly used for revegetation of degraded rangelands in the West Asia and North Africa regions. Seeds with and without their bracts (fruits) were subjected to physical (scarification, water soaking, gamma radiation)...

Barley (Hordeum vulgare) grown in Mediterranean regions undergoes drought stress during the grain-filling period. A greenhouse experiment was conducted to study the effect of drought stress on grain growth and yield of barley. Plants were exposed to three drought treatments at the beginning of grain filling: (1) well-watered at 100% field capacity,...

Accumulation of mineral nutrients in soybean seeds grown under drought stress may have a role in drought tolerance. Because drought stress reduces dry matter accumulation and seed size, drought stress may increase the concentration of mineral nutrients in soybean seeds and may decrease the content of nutrient per seed. The objective was to study th...

Stage of maturity can influence germination and dormancy of common vetch seeds. This experiment was initiated to study the seed germination and dormancy of fresh and air-dried seeds of common vetch and the methods to overcome seed dormancy during seed maturation. Pods were harvested at five developmental stages ranging from mid-seed fill (the seeds...

Bitter vetch is an important legume crop cultivated for forage and seed yield in the Mediterranean, West Asia, and North Africa regions. Delaying seed harvest of bitter vetch may increase seed losses due to pod shattering; however, early harvest may influence seed dormancy and the ability of seed to germinate. Field experiments were conducted at tw...

Field experiments were conducted during the winter seasons of 1999-2000 and 2000-2001 in the semi-arid region in the north of Jordan, to study the effect on yield responses of narbon vetch (Vicia narbonensis) of the following: seeding dates (14 Jan., 28 Jan. and 12 Feb.), seeding rates (40, 60 and 80 plants.m(-2)), phosphorus levels (17.5, 35.0 and...

Field experiments were conducted to detect the influence of varying N rates and weed control methods and 2, 4-D ester which was applied at two growth stages on yield, yield components, and phenological traits of barley. Among N rates significantly highest grain yield (2112.5 kg ha‾¹) was obtained under 120 kg N ha‾¹...

Thesis (M.S.)--Mississippi State University. Department of Plant and Soil Sciences. Includes bibliographical references.