Annals of the Academy of Romanian Scientists

Series on Agriculture, Silviculture and Veterinary Medicine

Volume 15, Number 1/2026

ISSN 2344-2085

47

DROUGHT TOLERANCE IN BARLEY (HORDEUM VULGARE L.):

PHYSIOLOGICAL AND GENETIC BASES AND MODERN

BREEDING STRATEGIES

Emanuela FILIP ¹, Camelia URDĂ ², Marius AIPĂTIOAIE ³,

Ioana BERINDEAN*⁴, Florin RUSSU*⁵

Abstract. Drought represents a major abiotic stress factor that significantly affects plant

growth, as well as physiological and metabolic processes, ultimately leading to reduced

cereal productivity worldwide. Under such conditions, plants respond through stomatal

closure, decreased photosynthetic activity, osmotic imbalance, and restricted nutrient

uptake. In Europe, including Romania, the frequency and intensity of drought and heat

stress events have increased, affecting barley (Hordeum vulgare L.), a species recognized

for its high adaptability and ecological plasticity. Drought tolerance is a complex,

polygenic trait involving numerous genes and quantitative trait loci (QTLs) associated

with essential adaptive mechanisms. The integration of breeding, physiological, and

genetic knowledge is essential for the development of valuable and well-adapted barley

genotypes, ensuring yield stability and contributing to food security under the conditions

imposed by ongoing climate change.

Keywords: barley, abiotic stress, yield stability, molecular breeding.

DOI

10.56082/annalsarsciagr.2026.1.47

1.Introduction

Drought represents one of the primary abiotic stress factors, causing significant

modifications at the level of plant growth, physiological processes, and

metabolism, with direct effects on global cereal production [28]. From an

agricultural perspective, it is defined as a state of soil moisture deficit, insufficient

to satisfy the requirements of a crop within a specific time interval [41]. Such

¹Eng., PhD., Emanuela FILIP, Agricultural Research and Development Station Turda, Romania,

Biotechnology and physico-chemical analysis laboratory, (e-mail: emanuelafilip33@gmail.com).

²Eng., PhD., Camelia URDĂ, Agricultural Research and Development Station Turda, Romania,

Biotechnology and physico-chemical analysis laboratory, (e-mail: camelia.urda@scdaturda.ro).

³Eng., PhD. Student, Marius AIPĂTIOAIE, Agricultural Research and Development Station

Turda, Romania, Biotechnology and physico-chemical analysis laboratory,

marius.aipatioaie@scdaturda.ro).

(e-mail:

⁴Prof., PhD., Eng., Ioana BERINDEAN, University of Agricultural Sciences and Veterinary

Medicine, Cluj-Napoca, Romania, (ioana.berindean@usamvcluj.ro).

⁵Eng., PhD., Florin RUSSU, Agricultural Research and Development Station Turda, Romania,

Barley breeding laboratory, (e-mail: florin.russu@scdaturda.ro ).

48

Emanuela Filip, Camelia Urda, Marius Aipatioaie, Ioana Berindean, Florin Russu

conditions are associated with reduced water availability, which determines

stomatal closure, decreased photosynthetic activity, leaf rolling, osmotic

imbalances, and the limitation of nutrient uptake [31].

Tolerance to drought and heat constitutes an essential factor for the stability of

agricultural yields, including in Romania, particularly in the steppe zones of the

south and east of the country, where these phenomena are frequent. In recent

years, drought has manifested increasingly often in the regions of Transylvania as

well, having a negative impact on production levels [29].

Starting with the 1980s, the frequency and intensity of drought episodes have

experienced a significant increase [35, 28]. Tolerance to drought and heat reflects

the capacity of plants to withstand prolonged periods of water stress and to

resume their physiological processes without significant reductions in potential

yield. In this context, the production level constitutes an essential indicator in the

evaluation of these traits. Water stress determines disturbances in the plant's water

balance, affecting fundamental physiological functions such as p hotosynthesis,

respiration, the transport of substances, and growth processes [29].

2.Materials and Methods

The method used to draft this paper consisted of documenting, analyzing, and

synthesizing specialized scientific literature published in international databases

(Scopus, Google Scholar, ScienceDirect). Climate, physiological, and genetic

studies relevant to barley cultivation were selected, with an emphasis on

identifying the genes involved in the drought response mechanism.

3.Results and Discussions

Climate change simultaneously generates both opportunities and risks for barley

production at a global level. Studies highlight that some early-maturing cultivars,

although presenting the advantage of avoiding the thermal stress occurring toward

the end of the vegetation period, are associated with inferior harvest quality and

do not manifest efficient mechanisms for drought avoidance. In this context,

under conditions where early forms are correlated with reduced qualitative

performance, increasing the number of productive secondary tillers is considered a

promising direction for breeding programs [21].

Barley possesses a series of traits that confer a certain degree of drought tolerance,

among which high photosynthetic efficiency stands out, associated with more

efficient water use and, implicitly, with the formation of a superior harvest index

and increased biomass [6]. Nevertheless, these advantages are accompanied by

Drought Tolerance in Barley (Hordeum vulgare L.):

Physiological and Genetic Bases and Modern Breeding Strategies

49

certain vulnerabilities, the crop being sensitive to variations in soil moisture and

thermal regime, particularly during the anthesis and post-anthesis phases,

corresponding to the grain-filling period [1].

Traditionally, drought is associated with regions such as Africa and Australia, but

recent observations indicate an intensification and expansion of drought

phenomena at the European level, these becoming more severe and having a wider

geographical distribution across the entire continent [22]. In recent decades, the

frequency of periods characterized by water deficit has increased especially in

Central and Western Europe. Studies highlight that the drought episodes of 2003,

2006, 2007, 2008, and 2011, particularly in the spring season, had a severe

economic impact on the agricultural sector [12]. In this context, climate

projections are considered worrying, especially for Central Europe, South-Eastern

Europe, and the Mediterranean region, where there is an increased risk of drought

intensification in the future.

A study regarding the impact of climate and climate change on European

agriculture involved the distribution of qualitative and quantitative questionnaires

to experts in agronomy and agroclimatology from 26 European countries. The

results indicate that European farmers are in an active process of adapting to

climate change, specifically through the use of early-maturing cultivars and the

selection of species and varieties with increased drought tolerance. The most

severe effects were reported in regions with a continental climate, particularly in

the Pannonian zone, which includes Hungary, Serbia, Romania, and Bulgaria.

These areas are characterized by a high frequency of heatwaves and drought

episodes, and cultivation cannot be planned efficiently for another interval of the

year [12].

The analysis of the impact of the stress factor and the phenophase in which

drought commonly occurs within a specific area represents an essential premise

for the breeding and improvement of drought tolerance [36].

In a study conducted at a local level in Cluj, Romania, it was highlighted that

temperatures during the post-anthesis phenophase have recorded a constant

upward trend in recent years, exceeding the multi-annual average. This aspect

indicates that heat stress phenomena are manifesting even in regions traditionally

considered favorable for barley cultivation, see Figure 1 [10].

50

Emanuela Filip, Camelia Urda, Marius Aipatioaie, Ioana Berindean, Florin Russu

Fig. 1. Changes in the average monthly temperature during the post-anthesis period over the last

67 years (1957–2024) in Turda, Romania [10].

In response to these climatic shifts, the development of new high-value cultivars

characterized by enhanced adaptability to current environmental conditions

becomes essential. Even in instances where water availability is not the primary

limiting factor, cereal crops exposed to elevated temperatures toward the end of

the growing season tend to record diminished yields [18, 38]. In the case of spring

cereals, this vulnerability is more pronounced due to their susceptibility to heat

stress. Within this framework, the work of plant breeders is becoming

increasingly complex, requiring the identification of novel sources of genetic

material to be utilized as donors for the development of superior genotypes aimed

at increasing drought tolerance [40].

Overall, improving drought tolerance in crop species represents an essential

requirement for maintaining yield levels and harvest quality [13].

Several studies highlight the existence of certain early-maturing barley cultivars

which, despite offering the advantage of early maturity, are associated with

reduced harvest quality and do not express efficient drought avoidance

mechanisms. Within this framework, the early forms analyzed are correlated with

inferior crop performance; consequently, increasing the number of productive

secondary tillers is considered a promising direction for breeding programs [21].

At the same time, plant architecture can constitute a relevant indicator for

evaluating drought resistance. The development of the root system, oriented

toward a more efficient exploration of the soil to access water resources,

represents a significant advantage under conditions of water deficit [17]

Drought Tolerance in Barley (Hordeum vulgare L.):

Physiological and Genetic Bases and Modern Breeding Strategies

51

Furthermore, [37] emphasize that tillering and leaf development represent

essential morphological traits involved in drought tolerance mechanisms.

The response of plants to water stress is based on the expression of a large number

of genes, which leads to the modification of cellular, physiological, and

biochemical processes, each contributing minor effects. Through the use of

transgenic techniques, multiple candidate genes (contributing candidate genes -

CGs) have been identified and are considered to be collectively involved in the

drought adaptation mechanisms of cereals, including barley [34, 20].

Genetic analyses have highlighted the localization of QTLs associated with

drought tolerance on chromosomes 2H, 5H, and 7H [9,19], these regions being

considered valuable genomic landmarks for the development of barley genotypes

with improved tolerance. The relationship between heading date (earliness) and

drought tolerance was highlighted by [23]. In this context, QTLs associated with

the heading moment were identified, located on chromosomes 2H, 5H, and 7H,

which show correlations with QTLs involved in drought tolerance. Furthermore,

QTLs related to yield components have been reported, situated in proximity to

those associated with earliness [21].

Despite the progress made in this field, a relatively limited number of genes

involved in the drought response have been tested, and evidence regarding their

direct contribution to increasing tolerance remains insufficient. The products of

these genes can be classified into two main categories: functional proteins,

involved in processes such as the transport of sugars and prolines, cellular

detoxification, the synthesis of late embryogenesis abundant (LEA) proteins, and

the regulation of osmotic balance; and regulatory proteins, which include

transcription factors, signaling molecules, and enzymes involved in phospholipid

metabolism [32].

Embryogenesis Abundant proteins is polygenic in nature; similarly, dehydration

processes are polygenically regulated, involving genes such as Dhn and LEA DII

[7, 4].

The literature further highlights other genes involved in drought tolerance

mechanisms. Specifically, the HvARH1 gene is associated with aldehyde

reduction processes [8], SRG6 is involved in protein synthesis under stress

conditions [17], and HVA1 participates in the synthesis of LEA-type proteins [2].

Additionally, the hVPPRPx gene is involved in regulating protein synthesis in

response to pathogen attack [30].

The HVA1 gene, involved in the synthesis of LEA-type proteins in barley, was

introduced into rice through transgenic methods, leading to increased tolerance of

this species to drought and salinity. These results support the hypothesis that LEA

proteins play an essential role in plant protection under water stress conditions.

52

Emanuela Filip, Camelia Urda, Marius Aipatioaie, Ioana Berindean, Florin Russu

Within this framework, the genes responsible for the synthesis of LEA proteins

represent valuable molecular tools in genetic breeding programs oriented toward

increasing drought resistance [43].

Abscisic acid (ABA) plays an essential role in mediating the plant response to

stress conditions and has been extensively investigated in barley and other cereal

species [25]. Within the framework of QTL analyses, traits associated with

drought tolerance include parameters such as leaf ABA content, relative water

content, and osmotic adjustment capacity [24, 37].

Wild barley germplasm (Hsp forms, HOR 11508) represents an important source

of QTLs with favorable effects on yield and other agronomic traits involved in

increasing resistance to water deficit, particularly in Mediterranean regions [11,

34].

Studies have enabled the identification of several genes involved in drought

tolerance, the mechanisms of which can be exploited in modern breeding

programs. To this end, 13 genes associated with drought resistance in barley are

presented in Table 1, highlighted in a comprehensive research study conducted by

[36].

Table 1. Key genes and their functional mechanisms in barley (Hordeum vulgare

L.) drought tolerance [36]

Gena

Mechanism of action

References

Membrane stability (dehydration

tolerance)

DHNs

[15]

Enhanced Chl a, b content,

stomatal conductance, biomass,

and grain yield

Dhn3, Dhn9

[15]

Overaccumulation of LEA

proteins improves drought

tolerance

LEA (HVA1)

DHNs

[16]

[15]

Membrane stability (dehydration

tolerance)

Leaf senescence and root

development

HvNACs

[5]

MYB

Growth and development

[39]

[20]

[26]

Cellular protection against

damage and desiccation

CBF/DREB

Vm-H1 și Vm-H2

Improved yield stability

Drought Tolerance in Barley (Hordeum vulgare L.):

Physiological and Genetic Bases and Modern Breeding Strategies

53

HvTX1

Grain development

[23]

[14]

Grain development under

drought conditions

HvDME

Cellular water absorption and

retention capacity

HVSRG6

[27]

[42]

Improved adaptation and

biomass accumulation following

water stress

HvWRKY38

Hsdr4

eibi1

Osmotic adjustment in barley

[33]

[3]

Maintenance of leaf water status

Recent studies in barley have highlighted significant progress in molecular

genetics, which has enabled the development and application of modern methods

to increase drought tolerance. In this context, several complementary genetic

strategies are being utilized. Genome-Wide Association Studies (GWAS) examine

the relationship between genetic variation and phenotypic traits, contributing to

the identification of candidate genes involved in the response to water stress.

Marker-Assisted Selection (MAS) allows for the rapid and efficient identification

of tolerant genotypes based on specific molecular markers. In parallel, genetic

engineering overcomes the limitations of classical breeding by directly

introducing stress tolerance-associated genes into the barley genome.

Furthermore, genome editing technologies offer a high level of precision,

allowing for targeted modifications of genes involved in plant adaptation to

drought conditions [1].

4.Conclusions

The intensifying severity and increasing frequency of drought and heat stress

phenomena necessitate a rapid adaptation of agricultural systems through the

development of more resilient genotypes. The integration of knowledge regarding

the physiological and genetic mechanisms of water stress tolerance, alongside the

use of classical methods complemented by modern breeding technologies,

represents an essential direction for ensuring yield stability and food security in

the context of climate change.

54

Emanuela Filip, Camelia Urda, Marius Aipatioaie, Ioana Berindean, Florin Russu

R E F E R E N C E S

[11] Anjum, S.A., Xie, X., Wang, L.C., Saleem, M.F., Morphological, physiological and

biochemical responses of plants to drought stress. African Journal of Agricultural Research

Vol. 6, 9, 2026-2032, (2011).

[12] Bahieldin, A., Mahfouz, H.T., Eissa, H.F., Saleh, O.M., Ramadan, A.M., Ahmed, I.A., Dyer,

W.E., El‐Itriby, H.A., Madkour, M.A., Field evaluation of transgenic wheat plants stably

expressing the HVA1 gene for drought tolerance. Physiologia Plantarum, 123, 4, pp.421-427,

(2005).

[13] Chen, G., Sagi, M., Weining, S., Krugman, T., Fahima, T., Korol, A.B. and Nevo, E., Wild

barley eibi1 mutation identifies a gene essential for leaf water conservation. Planta, 219, 4,

pp.684-693, (2004).

[14] Choi, D-W., Zhu, B., Close, T.J., The barley (Hordeum vulgare L.) dehydrin multigene

family: sequences, allele types, chromosome assignments, and expression characteristics of

11 Dhn genes of cv Dicktoo. Theoretical and Applied Genetics 98.8:1234-1247, (1999).

[15] Christiansen, M.W., Holm, P.B. & Gregersen, P.L., Characterization of barley (Hordeum

vulgare L.) NAC transcription factors suggests conserved functions compared to both

monocots and dicots. BMC Res Notes, 4, 302 (2011).

[16] Claesson, J., Nycander, J., Combined effect of global warming and increased CO2-

concentration on vegetation growth in water-limited conditions. Ecological Modelling, Vol.

256, 23-30, (2013).

[17] Close, T.J., Dehydrins: emergence of a biochemical role of a family of plant dehydration

proteins. Physiol Plant 97 795–803, (1997).

[18] Cseri, A., Cserháti, M., Von Korff, M., Nagy, B., Horváth, G.V., Palágyi, A., Pauk, J.,

Dudits, D. and Törjék, O., Allele mining and haplotype discovery in barley candidate genes

for drought tolerance. Euphytica, 181, 3, pp.341-356, (2011).

[19] Fan, Y., Shabala, S., Ma, Y., Xu, R., Zhou, M., Using QTL mapping to investigate the

relationships between abiotic stress tolerance (drought and salinity) and agronomic and

physiological traits. BMC Genomics 16:43. (2015).

[20] Filip, E., Urdă, C., Ciucă, M., Chețan, F., Șimon, A., Crișan, I., Aipătioaie, M., Hârța, M.,

Russu, F., Evaluation of Spring Barley Varieties for Post-Anthesis Drought Tolerance,

Romanian Agricultural Research, no 43, 611-620, (2026).

[21] Forster, B.P., Ellis, R.P., Moir, J., Talamé, V., Sanguineti, M.C., Tuberosa, R., This, D.,

Teulat-Merah, B., Ahmed, I., Mariy, S., Bahrii, H., Muahabi, M., Zoumarou-Wallis, N., El-

Fellah M., Salem, M.B., Genotype and phenotype association with drought tolerance in

barley tested in North Africa. Ann. Appl. Bioll. 44: 157 – 168, (2004).

[22] Joint Research Centre - European Commission, http://ies.jrc.ec.europa.eu. Accessed on

22.07.21.

[23] Kaczmarek, M., Fedorowicz-Strońska, O., Głowacka, K., Waskiewicz, A., CaCl₂treatment

improves drought stress tolerance in barley (Hordeum vulgare L.). Acta Physiol Plant 39: 41.

doi:10.1007/s11738-016-2336-y, (2017).

[24] Kapazoglou, A., Drosou, V., Argiriou, A. and Tsaftaris, A.S.,. The study of a barley

epigenetic regulator, HvDME, in seed development and under drought. BMC Plant

Biology, 13, 1, p.172, (2013).

Drought Tolerance in Barley (Hordeum vulgare L.):

Physiological and Genetic Bases and Modern Breeding Strategies

55

[25] Karami, A., Mabood H. E., Shahbazi M., Tafreshi R.S., Abedini R., Niknam V., Shobbar Z.,

Expression analysis of dehydrin multigene family across tolerant and susceptible barley

(Hordeum vulgare L.) genotypes in response to terminal drought stress. Acta Physiologiae

Plantarum, 35, pp. 2289-2297, (2013).

[26] Liang, J., Deng, G., Long, H., Pan, Z., Wang, C., Cai, P., Xu, D., Nima, Z.X. and Yu, M.,

Virus-induced silencing of genes encoding LEA protein in Tibetan hulless barley (Hordeum

vulgare ssp. vulgare) and their relationship to drought tolerance. Molecular Breeding, 30, 1,

pp.441-451, (2012).

[27] Malatrasi, M., Close, T.J., Marmiroli, N., Identification and mapping of a putative stress

response regulator gene in barley. Plant molecular biology, 50, 1, pp.141-150, (2002).

[28] McDonald, G.K., Sutton, B.G., Ellison, F.W., The effects of time of sowing on the grain

yield of irrigated wheat in Namoi Valley, New South Wales. Aust. J. Agric. Res. 34:229-40,

(1983).

[29] Mehravaran, L., Fakheri, B., Sharifi-Rad, J., Localization of quantitative trait loci (QTLs)

controlling drought tolerance in barley, Int J Biosci. 5: 248-259 (2014).

[30] Morran, S., Eini, O., Pyvovarenko, T., Parent, B., Singh, R., Ismagul, A., Eliby, S., Shirley,

N., Langridge, P. and Lopato, S., Improvement of stress tolerance of wheat and barley by

modulation of expression of DREB/CBF factors. Plant biotechnology journal, 9, 2, pp.230-

249, (2011).

[31] Ogrodowicz, P., Adamski, T., Mikołajczak, K., Kuczyńska, A., Surma, M., Krajewski, P.,

Sawikowska, A., Górny, A.G., Gudyś, K., Szarejko, I. and Guzy-Wróbelska, J., QTLs for

earliness and yield-forming traits in the Lubuski× CamB barley RIL population under various

water regimes. Journal of applied genetics, 58, 1, pp.49-65, (2017).

[32] Olesen, J.E., Trnka, M., KersebaumM Kc., Skjelvåg, Ao., Seguin, B., Peltonen-Sainio, P.,

Ross, F., Kozyra, J., Micale, F., Impacts and adaptation of European crop production systems

to climate change. Europ J Agronomy 34:96–112, (2011).

[33] Papaefthimiou, D. and Tsaftaris, A.S., Characterization of a drought inducible trithorax-like

H3K4 methyltransferase from barley. Biologia plantarum, 56, 4, pp.683-692, (2012).

[34] Quarrie, S.A., Galliba, G., Sutka, J, Snape, J.W., Semikhodskii, A., Steed, A., Gulli, M.,

Calestani, C., Association of a major vernalization gene of wheat with stress induced abcisic

acid production. In: Crop adaptation to Coll Climates Cost 814, Hamburg p. 403-414, (1994).

[35] Quarrie, S.A., Steed, A., Semikhodskii, A., Leberton, C., Lazie-Jancic, V., Pekic, S.,

Comparative QTL analysis of stress responses amongst cereals. In: Abstracts of proceedings

of the New Phytologist Symposium, langer, UK p. 13-14, (1997).

[36] Rollins, J.A., Drosse, B., Mulki, M.A., Grando, S., Baum, M., Singh, M., Ceccarelli, S. and

von Korff, M., Variation at the vernalisation genes Vrn-H1 and Vrn-H2 determines growth

and yield stability in barley (Hordeum vulgare) grown under dryland conditions in

Syria. Theoretical and Applied Genetics, 126, 11, pp.2803-2824, (2013).

[37] Romanek, J., Walczak, H., Wójcik-Jagła, M., Jurczyk, B. and Rapacz, M., The effect of

simulated drought on HVA1 and SRG6 gene expression in spring barley. Biotechnology, 14,

4, (2011).

[38] Safhi, F.A., Enhancing barley resilience: advanced genetic techniques to improve drought

tolerance for sustainable cultivation under current climatic fluctuations. Cereal Research

Communications, 53, 17–33, (2025).

[39] Savatti, M., Ardelean, M., Nedelea, G., Tratat de ameliorarea plantelor (Treatise of plant

breeding). Marineasa Publishing House, Timişoara, In Romanian (2004).

56

Emanuela Filip, Camelia Urda, Marius Aipatioaie, Ioana Berindean, Florin Russu

[40] Schmalenbach, I., Zhang, L., Reymond, M., Jiménez-Gómez, J.M., The relationship between

flowering time and growth responses to drought in the Arabidopsis Landsberg

erecta×Antwerp-1 population. Front. Plant Sci., Sec. Plant Genetics and Genomics Vol. 5,

(2014).

[41] Seleiman, M.F., Al-Suhaibani, N., Ali, N., Akmal, M., Alotaibi, M., Refay, Y., Dindaroglu,

T., Abdul-Wajid, H.H., Battaglia, M.L., Drought stress impacts on plants and different

approaches to alleviate its adverse effects. Plants, 10(2), p.259, (2021).

[42] Shinozaki, Y., Yamaguci-Shinozaki, K., Gene networks involved in drought stress response

and tolerance. J. Exp. Bot. 58: p. 221-227, (2007).

[43] Suprunova, T., Krugman, T., Distelfeld, A., Fahima, T., Nevo, E. and Korol, A.,

Identification of a novel gene (Hsdr4) involved in water-stress tolerance in wild barley. Plant

Molecular Biology, 64, 1, pp.17-34, (2007).

[44] Talamé, V., Sanguineti, M.C., Chiapparino, E., Bahri, H., Ben Salem, M., Forster, B.P., Ellis,

R.P., Rhouma, S., Zoumarou, W., Waugh, R., Tuberosa, R., Identification of H. spontaneum

QTL alleles improvming field performance of barley grown under rainfed conditions. Ann

Appl. Biol 144: 309 – 319, (2004).

[45] Tang, T., Ge, J., Shi, H., Wang, L., Cao, J., Lee, X., Drought frequency, intensity, and

exposure have increased due to historical land use and land cover changes. Commun Earth

Environ 6, 398, (2025).

[46] Tardieu, F., Any trait or trait-related allele can confer drought tolerance: just design the right

drought scenario. J Exp Bot.; 63,1:25–31. doi: 10.1093/jxb/err269, (2012).

[47] Teulat, B., This, D., Khaiallah, M., Borris, C., Ragot, C., Surdille, P., Leroy, P.,

Monnevueux, P., Charrier, A., Several QTLs involved in osmotic adjustment trait variation in

barley (Hordeum vulgare L.). Theoretical and Appl. Genet. 96: p. 688 698, (1998).

[48] Tewolde, H., Fernandez, C.J., Erickson, C.A., Wheat cultivars adapted to post heading high

temperature stress. J. Agron. Crop Sci. 192:111–120, (2006).

[49] Tombuloglu, H., Kekec, G., Sakcali, M.S. and Unver, T., Transcriptome-wide identification

of R2R3-MYB transcription factors in barley with their boron responsive expression

analysis. Molecular genetics and genomics, 288, 3, pp.141-155, (2013).

[50] von Korff, M., Grando, S., Del Greco, A., This, D., Baum, M., Ceccarelli, S., Quantitative

trait loci associated with adaptation to Mediterranean dryland conditions in barley. Theor

Appl Genet 117: 653–669. pmid:18618094, (2008).

[51] Wilhite, D.A., Glantz, M.H., Understanding the drought phenomenon: the role of definitions.

Water Int, 10:111–120, (1985).

[52] Xiong, X., James, V.A., Zhang, H. and Altpeter, F., Constitutive expression of the barley

HvWRKY38 transcription factor enhances drought tolerance in turf and forage grass

(Paspalum notatum Flugge). Molecular Breeding, 25, 3 , pp.419-432, (2010).

[53] Xu, D., Duan, X., Wang, B., Hong, B., Ho, T.H.D., Wu, R., Expression of a late

embryogenesis abundant protein gene, HVA1 from Barley Confers Tolerance to Water

Deficit and Salt Stress in Transgenic Rice. Journal List. Plant Physiol. V 110, 1, Jan., (1996).