Research Article

Polyethylene Glycol Mediated Osmotic Stress Impacts on Growth and Biochemical Aspects of Wheat Under Artificial Osmotic Stress Condition

Shabana Memon1*, Aamir Ali Abro1, Muhammad Iqbal Jakhro2, Aqsa Farid3, Maliha Habib4, Maqbool Ahmed5, Liaquat Ali Bhutto6, Saba Ambreen Memon7 and Muhammad Farooq8*

1Department of Plant Breeding and Genetics, Faculty of Crop Production Sindh Agriculture University Tandojam, Pakistan; 2PARC-Balochistan Agriculture Research and Development Centre, Western Bypass Brewery Road, Quetta, Balochistan, Pakistan; 3Institute of Biotechnology and Genetic Engineering, The University of Agriculture, Peshawar, Khyber Pakhtunkhwa, Pakistan; 4Sardar Bahadur Khan Women’s University Brewery Road, Quetta, Balochistan, Pakistan; 5Directorate of Agriculture Extension Rani Bagh, Quetta, Balochistan, Pakistan; 6Agriculture Research Center, Tandojam, Pakistan; 7Department of Horticulture, Faculty of Crop Production, Sindh Agriculture University Tandojam, Pakistan. 8College of Food Science and Engineering, Northwest A and F University, Yangling, Shaanxi 712100, PR China.

Received | February 03, 2023; Accepted | February 13, 2023; Published | March 02, 2023

*Correspondence | Shabana Memon and Muhammad Farooq, Department of Plant Breeding and Genetics, Faculty of Crop Production Sindh Agriculture University Tandojam, Pakistan; College of Food Science and Engineering, Northwest A and F University, Yangling, Shaanxi 712100, PR China; Email: [email protected], [email protected]

Citation | Memon, S., A.A. Abro, M.I. Jakhro, A. Farid, M. Habib, M. Ahmed, L.A. Bhutto, S.A. Memon and M. Farooq. 2023. Polyethylene glycol mediated osmotic stress impacts on growth and biochemical aspects of wheat under artificial osmotic stress condition. Journal of Innovative Sciences, 9(1): 44-50.

DOI | https://dx.doi.org/10.17582/journal.jis/2023/9.1.44.50

Keywords | Wheat, PEG 6000, Ionic content, Morphology, Osmotic stress

Copyright: 2023 by the authors. Licensee ResearchersLinks Ltd, England, UK.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

1. Introduction

Being a worldwide restriction, drought has shown to have a significant influence on productivity (Li et al., 2020; Abro et al., 2020). Each stage of plant growth is eventually impacted by the impacts of drought on crop output. Additionally, there is a reduction in germination potential, coleoptile length, and vigour (Mahpara et al., 2022; Abro et al., 2019). The primary limiting variables for germination are semi-arid locations and low moisture places. The production of seedlings and their rate can be used to predict the maturity and yield of H. hirsutum (Sharma et al., 2022).

A popular in vitro selection technique is polyethylene glycol (PEG), which is used to weed out cultivars that can withstand drought (Tabatabai et al., 2022). It causes osmotic stress in plants and has a big impact on how quickly their roots and shoots grow (Latif et al., 2022). The nonionic, almost impermeable chains of the PEG molecules (PEG 6000) maintain the homogeneity of water potential throughout the experiment without harming people’s health (Vuković et al., 2022). The research on identifying drought-resistant wheat genotypes have demonstrated that various features respond differently to varying amounts of PEG-6000 (Batool et al., 2022; Abro et al., 2021). According to (Abro et al., 2022; Hussain et al., 2022) decrease in the length of vegetative organs (such as the stem, plumule, and coleoptile) and a drop in the proportion of seeds that germinate as a result of the severity of moisture stress may not be a reliable signal for choosing resistant cultivars. Coleoptile lengths and leaf surface areas decline early in wheat development (Lei et al., 2021; Abro et al., 2021). Low germination rates would ensue as a result, which would decrease the likelihood of planting in damp soil (Manoj et al., 2021).

The osmotic stress brought on by the drought brought on by the depletion of subterranean water (PEG) influences ion transport and absorption throughout the plant’s life cycle, from growth to crop production (Loutfy et al., 2022). An efficient method for modifying physiological characteristics and genetic processes that result in the breeding of superior cultivars is in-vitro drought resistance screening (Mahpara et al., 2022). Scientists are concentrating on increasing the output capacity of wheat through developing new varieties of bread wheat that have a favourable genetic makeup (Pandey et al., 2022). Increasing productivity and crop yield per unit area was the goal in primitive times. Because hybridization can best use the gene, genetically modified wheat can be very successful. Genetic modification is the best method for improving wheat production (Sharma et al., 2022). The only way to select wheat genotypes is if there is strain heterogeneity. Earlier researchers looked at the phenotypic correlation coefficients of different grain yield and its components with crop yield in terms of genetic improvement through a variety of experiments. Othmani et al. (2021) discovered that grain weight in the 1000-grain range had an effect on grain yield (Bijalwan et al., 2022). Assert that tillers plant-1 significantly contributed to grain yield. The objective of the current study is to filter for wheat genotypes that is drought resistant using polyethylene glycol (PEG-6000) liquid in a laboratory environment. The same genotypes were also examined in the field to further support the laboratory research. Our research compared the performance of different wheat genotypes based on morpho-physiological characteristics in both in vitro and in vivo tests. The wheat (Triticum aestivum L.) genotypes that were stressed at the seedling stage were also removed using PEG-6000. Our research compared the performance of different wheat genotypes based on morpho-physiological characteristics in both in vitro and in vivo tests. Additionally, we eliminated wheat (Triticum aestivum L.) genotypes that were stressed at the seedling stage using PEG-6000.

2. Materials and Methods

The current study was carried out in the Rabi year of 2021 by the Tandojam Plant Physiology Division of the Nuclear Institute of Agriculture (NIA). 06 wheat genotypes were excluded from the experiment under control conditions (1/4th Hoagland solution) in addition to a simulated drought of 0.5 MPa caused by Polyethylene glycol-6000. These genotypes included V1 AST-1, V2 AST-1, V3 SDW-1, V4 SDW-2, V5 SDW-3, V6, and Khirman (PEG-6000). The Plant Breeding and Genetics Division (PBGD) of the Nuclear Institute of Agriculture (NIA) in Tandojam provided the different wheat germplasm samples (the advanced lines). The study took place in a growth cabinet with a 25/25°C daytime and 12°C nighttime temperature control. It was factorially set up in a fully randomised design (CRD), and it was duplicated three times (irradiance: 22 Wm-2). The seedlings in each treatment were cultivated on plastic moulded nets and put in 8.5 cm diameter bowls after being surface sterilised with 0.5 percent NaCl (sodium hypochlorite) on 30 wheat seeds from each genotype (Abro et al., 2021, 2020). For 72 hours, the bowls were kept in the dark to guarantee a successful germination process. The seeds were exposed to a 12-hour photoperiod for 11 days (irradiance: 22 Wm-2). 06 wheat genotypes were discarded from the study under control circumstances (1/4th Hoagland solution), and polyethylene glycol-6000 was used to mimic a drought of 0.5 MPa (PEG-6000). When necessary, Ca (OH) 2 and/or H2SO4 were used to assess the nutritional solution’s pH and adjust it to 5.5 + 0.2. The plants were removed carefully ten days after planting, separated into shoots and roots, thoroughly cleansed with filtered water, and blotted dry. After being weighed dry for the shoot and root, the materials were thoroughly treated in a wiley mill to pass through with a 1 mm (40 mesh) filter. Uniformly ground materials were digested with a di-acid mixture of nitric (HNO3) and per chloric (HClO4) at a 3:1 ratio. Using a flame photometer (Jenway PFP-7) to calculate the potassium content in the shoot and root (mg g-1dry wt) in accordance with (Abro et al., 2020, 2021; Wei et al., 2013).

2.1 Statistical analysis

Data were examined by Gomez and Gomez using the statistical method of analysis of variance (Gomez and Gomez, 1984). When the F-test was significant, a multiple mean comparison analysis incorporating the variety and stress therapy was performed. Tukey’s significant difference was then utilised to determine the treatment combinations.

3. Results and Discussion

In this work, an in-vitro environment was used to assess the ability of the six wheat cultivars to survive water stress induced by PEG (6000) at the early seedling stage. Six distinct wheat cultivars had varying performances under the various PEG treatments, according to statistical analysis data. There was a substantial two-way interaction between cultivars and the amount of drought for all seedling measures (P 0.01). The mean square of analysis at the vegetative stages for the nutrient uptake, including shoot (length), root (length), shoot (fresh wt), root (fresh wt), shoot (dry wt), and potassium (K) percent, revealed highly significant difference at P0.01 and P0.05 probability level for all traits for genotypes, treatments, and interaction (Table 1).

 

Table 1: In vitro effect of drought condition on shoot length (cm) of wheat genotypes.

S. No	Genotypes	Control		Drought		Mean		R. Dec (%)
1	AST-I(V1)	16.58	AB	15.53	BC	16.055	AB	6.4
2	AST-I(V6)	15.85	ABC	13.04	DE	14.443	C	17.7
3	SDW-1	17.56	A	16.04	ABC	16.8	A	8.7
4	SDW-2	16.96	AB	14.59	CD	15.778	AB	14.0
5	SDW-3	11.87	E	13.21	DE	12.543	D	-11.3
6	Khirman	16.06	ABC	15.18	BC	15.622	B	5.5
	Mean	15.82	A	14.60	B			7.7

 

HSD (0.05); Treat =0.44; Geno = 1.15; T x G = 1.90

 

3.1 Shoot and Root length

Under control conditions, SDW-1 (17.56 cm) had the longest shoots on average while SDW-3 (11.87 cm) had the shortest. Whereas, in drought conditions, the SDW-1 maximum shoot length was 16.04 cm, and the AST-I minimum was V6 (13.04 cm). However, Khirman showed the lowest reduced R.D (5.5%) and AST-I showed the most decreased (17.7 %%). (V6). In an in vitro investigation, wheat genotypes were examined to see how their root length responded to drought circumstances (moisture stress). The results (Tables 2, 3) revealed that the tested wheat genotypes responded differently to drought conditions. SDW-3 (7.05 cm) had the shortest root length while AST-I (V1) had the longest root length at the maximum

 

Table 1: Mean square of analysis for different growth parameters under osmotic stress using PEG (6000).

Source	DF	Shoot (length)	Root (length)	Shoot (fresh wt)	Root (fresh wt)	Shoot (dry wt)	Root (dry wt)	Potassium (K) %
Replication	2	0.1008	0.0910	0.0227	0.04110	0.00049	0.00064	4.6978
Genotypes	5	13.7201**	13.6548**	0.1220**	0.06717ns	0.1310**	0.00794**	16.5458*
Treatment	1	13.3103**	10.2187*	17.6931**	0.58303**	0.03277**	0.05505**	25.3344*
Genotype x treatment	5	3.1948**	8.2668**	1.0429**	0.22056**	0.01150**	0.00351**	22.8318**
Error	22	0.4096	1.6852	0.0718	0.02764	0.00091	0.00029	5.7472

 

**: significant at <0.01probability level; *: Significant at P<0.05probability level and ns.: non-significant.

 

Table 2: In vitro effect of drought condition on root length (cm) of wheat genotypes.

S. No	Genotypes	Control		Drought		Mean		R. Dec (%)
1	AST-I(V1)	13.71	A	11.78	AB	12.75	A	14.1
2	AST-I(V6)	10.38	ABC	11.38	AB	10.88	AB	-9.6
3	SDW-1	8.62	BC	10.46	ABC	9.54	B	-21.3
4	SDW-2	12.22	AB	12.27	AB	12.24	A	-0.4
5	SDW-3	7.05	C	12.17	AB	9.61	B	-72.6
6	Khirman	12.64	A	12.96	A	12.80	A	-2.5
	Mean	10.77	B	11.84	A			-9.9

 

HSD (0.05); Treat =0.90; Geno = 2.33; T x G = 3.85

 

Table 3: In vitro effect of drought condition on shoot fresh weight (g) of wheat genotypes.

S. No	Genotypes	Control		Drought		Mean		R. Dec (%)
1	AST-I(V1)	3.93	B	2.69	C	3.31	A	31.6
2	AST-I(V6)	4.67	AB	2.47	C	3.57	A	47.0
3	SDW-1	4.06	AB	2.50	C	3.28	A	38.5
4	SDW-2	4.74	A	2.61	C	3.68	A	44.8
5	SDW-3	2.46	C	2.57	C	2.52	B	-4.4
6	Khirman	4.34	AB	2.93	C	3.64	A	32.3
	Mean	4.03	A	2.63	B			34.8

 

HSD (0.05); Treat =0.19; Geno = 0.48; T x G = 0.80

 

under control conditions. However, in Khirman, the greatest root length measured under drought conditions was 12.96 cm, while the minimum SDW-1 (10.46 cm). However, the AST-I test showed a relative reduction of 14.1%. (V1). The main factors for choosing wheat cultivars that are drought-resistant relate to plant growth, such as root and shoot length, seedling fresh weight, etc. (Abro et al., 2020, 2021; Foito et al., 2009). It is also obvious that different cultivars’ shoot lengths are considerably impacted by water stress caused by PEG. Because cell division and shoot elongation both require artificial osmotic stress. The researcher found that PEG had an effect on the shoot length of numerous wheat varieties in his study experiment and came to similar conclusions (Almaghrabi, 2012). This explanation states that the root length reduces with increasing PEG concentrations, possibly as a result of the inhibition of cell division and elongation (Doneva et al., 2021). The reduction in root length during drought stress may be due to a limitation of cell division and elongation that results in soft tuberization, claim Chachar et al. (2014).

3.2 Shoot and root fresh weight (g)

In an in vitro investigation, wheat genotypes were examined for how they responded to moisture stress and drought in terms of shoot fresh weight, and the results (Table 3) revealed that the tested wheat genotypes responded differently to drought. Under control conditions, SDW-2 showed the highest shoot fresh weight (4.74 g), while SDW-3 showed the lowest (2.46 g). While in a drought, Khirman had the highest fresh shoot weight (2.93 g) and the lowest AST-I (V6) levels (2.47 g). A lowest reduced R.D of 44.8 percent was found in SDW-2, whilst a maximum decreased R.D of 32.3 percent was found in Khirman. In an in vitro experiment, wheat genotypes were examined to see how drought circumstances (moisture stress) affected the root fresh weight of the plants. The results (Table 4) revealed that the tested wheat genotypes responded to drought in different ways. Under control conditions, AST-I (V6) (1.98 g) had the highest root fresh weight and SDW-3 (1.43 g) had the lowest. Whereas, in drought conditions, SDW-3 recorded the highest root fresh weight (1.84 g), while SDW-1 recorded the lowest (1.12 g). However, Khirman showed the lowest reduced R.D (12.7%) and SDW-1 showed the most decreased (38.6%). Our findings concur with those made by (Abro et al., 2020, 2021; Wei et al., 2013), who saw a trend of decline in the shoot and root’s fresh/dry weight. However, it was noticed by multiple studies that the both variables of shoot/root fresh and dry weight greatly increased shoot and root masses in both cultivars under well-watered circumstances.

 

Table 4: In vitro effect of drought condition on root fresh weight (g) of wheat genotypes.

S. No	Genotypes	Control		Drought		Mean		R. Dec (%)
1	AST-I(V1)	1.65	ABC	1.40	BCD	1.52	A	15.3
2	AST-I(V6)	1.98	A	1.42	BCD	1.70	A	28.4
3	SDW-1	1.82	AB	1.12	D	1.47	A	38.6
4	SDW-2	1.52	ABCD	1.32	CD	1.42	A	13.5
5	SDW-3	1.43	BCD	1.84	AB	1.64	A	-28.3
6	Khirman	1.69	ABC	1.47	BCD	1.58	A	12.7
	Mean	1.68	A	1.43	B			15.1

 

HSD (0.05); Treat =0.12; Geno = 0.30; T x G = 0.49

 

3.3 Shoot and root dry weight (g)

In the in vitro experiments, wheat cultivars were tested for how drought-related moisture stress affected their shoot dry weight. The results (Table 5) showed that the tested wheat genotypes reacted to drought in different ways. Under control conditions, SDW-2 (0.51 g) had the highest shot dry weight while SDW-3 (0.29 g) had the lowest shoot dry weight. While under drought conditions, the highest shoot dry weight (SDW-3) measured was 0.41 g, and the lowest (AST-I) was V1 (0.31 g). However, Khirman showed the lowest reduced R.D (15.0%) and AST-I showed the most decreased (24.7%) (V6). In an in vitro experiment, wheat genotypes were examined to see how drought circumstances (moisture stress) affected the root dry weight of the plants. The results (Table 6) revealed that the tested wheat genotypes responded to drought in different ways. Under regulated conditions, SDW-3 had the highest root dry weight (0.34 g), whereas Khirman had the lowest (0.19 g). However, in times of dryness, SDW-1’s highest root dry weight (0.19 g) and AST-lowest I’s (V1) were also recorded (0.12 g). A minimum reduced R.D of 21.0 percent was found in SDW-1, whilst a maximum decreased R.D of 52.0 percent was found in SDW-3. Other studies that found that water stress had a significant influence on root and shoot dry matter production (Abro et al., 2020, 2021; Ahmad et al., 2013; Marciska et al., 2013) also noticed a downward trend in root and shoot dry weight.

 

Table 5: In vitro effect of drought condition on shoot dry weight (g) of wheat genotypes.

S. No	Genotypes	Control		Drought		Mean		R. Dec (%)
1	AST-I(V1)	0.38	BCDE	0.31	DE	0.34	C	19.0
2	AST-I(V6)	0.45	AB	0.34	CDE	0.39	BC	24.7
3	SDW-1	0.50	A	0.39	BCD	0.44	AB	22.4
4	SDW-2	0.51	A	0.39	BCD	0.45	A	23.3
5	SDW-3	0.29	E	0.41	BC	0.35	C	-37.9
6	Khirman	0.41	BC	0.34	CDE	0.37	C	15.0
	Mean	0.42	A	0.36	B			14.3

 

HSD (0.05); Treat = 0.02; Geno = 0.05; T x G = 0.09

 

Table 6: In vitro effect of drought condition on root dry weight (g) of wheat genotypes.

S. No	Genotypes	Control		Drought		Mean		R. Dec (%)
1	AST-I(V1)	0.18	DEF	0.12	G	0.15	D	31.2
2	AST-I(V6)	0.22	BCD	0.16	EFG	0.19	BC	26.8
3	SDW-1	0.24	BC	0.19	CDEF	0.21	B	21.0
4	SDW-2	0.26	B	0.18	DEF	0.22	B	29.6
5	SDW-3	0.34	A	0.16	EFG	0.25	A	52.0
6	Khirman	0.19	CDE	0.14	FG	0.17	CD	27.9
	Mean	0.16	B	0.24	A			-49.3

 

HSD (0.05); Treat =0.01; Geno = 0.03; T x G = 0.05

 

3.4 Potassium content (%)

In an in vitro experiment, the potassium content of wheat genotypes was screened to determine how they would react to moisture stress and drought. The results (Table 7) revealed that the tested wheat genotypes responded differently to drought. Under controlled conditions, SDW-3 had the greatest potassium content (22.20%), while AST-I had the lowest amount (V6) (18.0%). The lowest SDW-1 levels and maximum potassium concentration in AST-I (V1) (25.27%) were discovered during drought circumstances (17.73%). SDW-1 had the lowest reduced R.D (2.7%) and SDW-3 had the highest decreased R.D (18.6%). This might be explained by the fact that higher K+ concentrations in the soil provided roots with more possibilities to absorb K+ and that cellular membrane recovery increased K+ conservation in plant tissues. Study from (Abro et al., 2020, 2021; Wei et al., 2013) supports the findings of his study, which discovered that enough exogenous K+ significantly increased K+ contents in both the shoot and root of PEG6000-stressed plants.

 

Table 7: In vitro effect of drought condition on potassium content (%) of wheat genotypes.

S. No	Genotypes	Control		Drought		Mean		R. Dec (%)
1	AST-I(V1)	20.50	ABC	25.27	A	22.88	A	-23.3
2	AST-I(V6)	18.00	BC	24.97	AB	21.48	AB	-38.7
3	SDW-1	18.23	ABC	17.73	C	17.98	B	2.7
4	SDW-2	19.03	ABC	20.47	ABC	19.75	AB	-7.5
5	SDW-3	22.20	ABC	18.07	BC	20.13	AB	18.6
6	Khirman	20.07	ABC	21.60	ABC	20.83	AB	-7.6
	Mean	19.67	B	21.35	A			-8.5

 

HSD (0.05); Treat =1.66; Geno = 4.31; T x G = 7.12

 

Conclusions and Recommendations

The current study demonstrates that, both in vitro and in vivo, osmotic stress significantly lowered its seeds incubated, root length, and shoot fresh and dry weight throughout all six wheat cultivars. The greatest reduction was found in the genotype SDW-3 when PEG-6000-induced enhanced osmotic stress was present (-5.0 MPa). AST-1(V1), SDW-1, and SDW-2 as a consequence. The results demonstrated that the osmotic impact was larger when PEG was applied at a pressure of -0.5 MPa. With an increase in PEG (-0.5 MPa) level, the genotype SDW-3 reduced various growth parameters, including shoot length, root length, and shoot fresh weight, more during the seedling stage. It was suggested that these genotypes may be used in next breeding initiatives and taken into consideration as genotypes resistant to drought.

Novelty Statement

These wheat cultivars which were under observation of for study on the basis of our study we can strongly suggested that wheat cultivator can be utilize in drought stress areas.

Author’s Contribution

Shabana Memon and Aamir Ali Abro: Conceptualization, methodology, for-mal analysis, writing-original draft.

Muhammad Iqbal Jakhro: Helped in methodology section

Aqsa Farid: Helped in introduction section.

Maliha Habib and Maqbool Ahmed: helped in analysis

Liaquat Ali Bhutto and Saba Ambreen Memon: helped in research

Muhammad Farooq: Conceptualization, review the manuscript and amp; editing

Conflict of interest

The authors have declared no conflict of interest.

References

Abro, A.A., Akher, S.A., Memon, S., Huda, M.N., Abro, S.A., and Jahan, S.N., 2021. Influence of polyethylene glycol (PEG 6000) generate osmotic stress on seed germination of different wheat (Triticum aestivum L.) Genotypes.

Abro, A.A., Eisawi, K.A., Batyrbek, M., Sial, N.Y., Akhtar, M., and Memon, S.A., 2021. Identification of drought-tolerant wheat (Triticum aestivum L) cultivars based on the associations of in-vitro and in-vivo predictors through polyethylene glycol (peg 6000) mediated osmotic STRESS. Pakistan Journal of Biotechnology, 18(3-4): 69-80. https://doi.org/10.34016/pjbt.2022.19.1-2.69

Abro, A.A., Khoso, A.G., Eisawi, K.A.E., Abdelghany, A.E.A., Batyrbek, M.B., Sial, N.Y., and Zahoor, M.U., 2022. Study on correlations for morpho-physio traits of six wheat cultivars. Journal of Applied Research in Plant Sciences, 3(1): 198-205. https://doi.org/10.38211/joarps.2022.3.1.24

Abro, A.A., Memon, S., Abro, S.A., Magsi, F.H., Soomro, A.A., Mahar, N.A., and Chang, B.H., 2019. Influence of additional amino acids in growth of different wheat (Triticum aestivum L) genotypes. Journal of Plant Nutrition, 42(19): 2539-2551. https://doi.org/10.1080/01904167.2019.1659318

Abro, A.A., Memon, S., Abro, S.A., Sam, E.K., He, R.Y., Rind, M.H., and Kumbhar, R.A., 2020. Evaluation of drought tolerance in wheat (Triticum aestivum L.) cultivars at early seedling stage using polyethylene glycol induced osmotic stress. Journal of Animal and Plant Sciences, 30(4): https://doi.org/10.36899/JAPS.2020.4.0111

Ahmad, M., Shabbir, G., Minhas N., and Shah, M.K.N., 2013. Identification of drought tolerant wheat cultivars based on seedling traits. Sarhad. J. Agric., 29(1): 21-27.

Almaghrabi, O.A., 2012. Impact of drought stress on germination and seedling growth parameters of some wheat cultivars. Life Sci. J., 9(1): 590-598.

Batool, M., El-Badri, A.M., Wang, Z., Mohamed, I.A., Yang, H., Ai, X., and Zhou, G., 2022. Rapeseed Morpho-Physio-Biochemical Responses to Drought Stress Induced by PEG-6000. Agronomy, 12(3): 579. https://doi.org/10.3390/agronomy12030579

Bijalwan, P., Sharma, M., and Kaushik, P., 2022. Review of the effects of drought stress on plants: A Systematic Approach. https://doi.org/10.20944/preprints202202.0014.v1

Chachar, M., Chachar, N., Chachar, S., Chachar, Q., Mujtaba, S. and Yousafzai, A., 2014. In-vitro screening technique for drought tolerance of wheat (Triticum aestivium L.) cultivar s at early seedling stage. J. Agric. Tech., 10(6): 1439-1450.

Doneva, D., Pál, M., Brankova, L., Szalai, G., Tajti, J., Khalil, R., and Peeva, V., 2021. The effects of putrescine pre-treatment on osmotic stress responses in drought-tolerant and drought-sensitive wheat seedlings. Physiologia Plantarum, 171(2): 200-216. https://doi.org/10.1111/ppl.13150

Foito, A., Byrne, S.L., Shepherd, T., Stewart, D. and Barth, S., 2009. Transcriptional and metabolic profiles of (Lolium perenne L.) cultivar s in response to a PEG-induced water stress. Plant Biotech. J., 7(8): 719-732. https://doi.org/10.1111/j.1467-7652.2009.00437.x

Gomez, K.A. and Gomez, A.A. 1984. Statistical Procedures for Agricultural Research. 2nd Edition, John Wiley and Sons, New York, 680 p.

Hussain, S., Ali, B., and Saqib, M., 2022. Seed priming to enhance salt and drought stress tolerance in plants: Advances and prospects. Climate Change and Crop Stress, pp. 441-464. https://doi.org/10.1016/B978-0-12-816091-6.00012-2

Latif, M., Bukhari, S.A.H., Alrajhi, A.A., Alotaibi, F.S., Ahmad, M., Shahzad, A.N., and Mattar, M.A., 2022. Inducing drought tolerance in wheat through exopolysaccharide producing rhizobacteria. Agronomy, 12(5): 1140. https://doi.org/10.3390/agronomy12051140

Lei, C., Bagavathiannan, M., Wang, H., Sharpe, S.M., Meng, W., and Yu, J., 2021. Osmopriming with polyethylene glycol (PEG) for abiotic stress tolerance in germinating crop seeds: A review. Agronomy, 11(11): 2194. https://doi.org/10.3390/agronomy11112194

Li, D., Batchelor, W.D., Zhang, D., Miao, H., Li, H., Song, S., and Li, R., 2020. Analysis of melatonin regulation of germination and antioxidant metabolism in different wheat cultivars under polyethylene glycol stress. PLoS One, 15(8): e0237536. https://doi.org/10.1371/journal.pone.0237536

Loutfy, N., Hassanein, A.M., Inouhe, M., and Salem, J.M., 2022. Biological aspects and proline metabolism genes influenced by polyethylene glycol and salicylic acid in two wheat cultivars. Egyptian Journal of Botany. 62(3): 671-685. https://doi.org/10.21608/ejbo.2022.124280.1921

Mahpara, S., Zainab, A., Ullah, R., Kausar, S., Bilal, M., Latif, M.I., and Zuan, A.T.K., 2022. The impact of PEG-induced drought stress on seed germination and seedling growth of different bread wheat (Triticum aestivum L.) genotypes. PLoS One, 17(2): e0262937. https://doi.org/10.1371/journal.pone.0262937

Manoj, N.V., Chaudhary, H.K., and Singh, K., 2021. Screening of potential wheat genotypes for drought tolerance using polyethylene glycol. Himachal Journal of Agricultural Research, 46(2): 130-135.

Marcińska, I., Czyczyło-Mysza, I., Skrzypek, E., Filek, M., Grzesiak, S., Grzesiak, M.T., and Dziurka, K., 2013. Impact of osmotic stress on physiological and biochemical characteristics in drought-susceptible and drought-resistant wheat cultivars. Acta Physiol. Plantarum. 35(2): 451-461. https://doi.org/10.1007/s11738-012-1088-6

Othmani, A., Ayed, S., Chamekh, Z., Slama-Ayed, O., Teixeira Da Silva, J., Rezgui, M., and Ben Younes, M., 2021. Screening of seedlings of durum wheat (Triticum durum Desf.) cultivars for tolerance to peg-induced drought stress. Pakistan Journal of Botany, 53(3): 823-832. https://doi.org/10.30848/PJB2021-3(5)

Pandey, A., Khobra, R., Mamrutha, H.M., Wadhwa, Z., Krishnappa, G., Singh, G., and Singh, G.P., 2022. Elucidating the drought responsiveness in wheat genotypes. Sustainability, 14(7): 3957. https://doi.org/10.3390/su14073957

Sharma, K., Dhingra, M., Kaur, R., Singh, S., Kaur, A., Kaur, S., and Sharma, A., 2022. Evaluation of Triticum durum. Aegilops tauschii derived primary synthetics as potential sources of drought stress tolerance for wheat improvement. Cereal Research Communications, pp. 1-12. https://doi.org/10.1007/s42976-022-00265-2

Sharma, V., Kumar, A., Chaudhary, A., Mishra, A., Rawat, S., Shami, V., and Kaushik, P., 2022. Response of wheat genotypes to drought stress stimulated by PEG. Stresses, 2(1): 26-51. https://doi.org/10.3390/stresses2010003

Tabatabai, S.M.T., Goshasbi, F., and Bakhshi, B., 2022. Evaluation of the effect of polyethylene glycol (PEG) on germination and morphological characteristics of bread wheat. Cereal Research Communications, pp. 1-7. https://doi.org/10.1007/s42976-022-00242-9

Vuković, R., Čamagajevac, I.Š., Vuković, A., Šunić, K., Begović, L., Mlinarić, S., and Španić, V., 2022. Physiological, biochemical and molecular response of different winter wheat varieties under drought stress at germination and seedling growth stage. Antioxidants, 11(4): 693. https://doi.org/10.3390/antiox11040693

Wei, J., Li, C., Li, Y., Jiang, G., Cheng, G., and Zheng, Y., 2013. Effects of external potassium (K) supply on drought tolerances of two contrasting winter wheat cultivars. PLoS One, 8(7): 69737. https://doi.org/10.1371/journal.pone.0069737