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. 2016 May 4;7:597. doi: 10.3389/fpls.2016.00597

Exogenous Application of Growth Enhancers Mitigate Water Stress in Wheat by Antioxidant Elevation

Hamid Nawaz 1, Azra Yasmeen 1, Muhammad A Anjum 2, Nazim Hussain 1,*
PMCID: PMC4854884  PMID: 27200065

Abstract

The present study was conducted to investigate the response of two wheat cultivars (AARI-11 and Millat-11) to a foliar application of four growth enhancers which include: {H2O (water), MLE30 (moringa leaf extract), KCl (potassium chloride), and BAP (benzyl-amino purine)}, within the six irrigation water-regimes which are applied at the various critical growth stages such as crown root initiation (CRI), tillering (T), booting (B), and heading (H). Irrigation water-regimes include: CRI+T+B, CRI+T, CRI+B, T+B, T+H, and control (CRI+T+B+H). The growth enhancers i.e., H2O, MLE30 (1:30), KCl (2%), and BAP (50 mg L−1) were applied @ 500 L ha−1 at tillering and heading stages. The results demonstrated some increased quantities of both enzymatic (superoxide dismutase, peroxidase, catalase) and non-enzymatic (ascorbic acid, phenol) antioxidants in leaves of AARI-11 when MLE30 was applied under T+B and T+H irrigation water-regimes. Similar results were also observed in the case of leaf chlorophyll “a” and “b” and K+ contents in both cultivars under control, T+B and CRI+T+B irrigation water regimes. AARI-11 produced the highest biological and grain yield, due to the application of MLE30 and BAP under control, CRI+T+B, T+B, and T+H irrigation water-regimes. However, KCl lagged behind among the treatments set for both cultivars under all the irrigation water-regimes. Foliar spray of MLE30 remained prominent growth enhancer and stresses mitigating agent under water deficit conditions particularly under T+B and T+H irrigation water-regimes. Moreover, economic analysis indicated that the foliar application of MLE30 is a cost effective and environment friendly strategy for the maximum yield and income.

Keywords: enzymes, non-enzymes, benefit cost ratio, growth regulators, irrigation water-regimes

Introduction

Wheat (Triticum aestivum L.) is one of the most important feeding cereals for one-fifth of the world population (FAO, 2011). Therefore, wheat crops require a special attention for an incremental production in order to ease the food security issues for the world population which is growing so rapidly. Today, Wheat plants are facing oxidative damage at cellular level which reduces leaf surface area, crop growth rate, net assimilation rate, leaf chlorophyll and nutrient contents in grains due to insufficient availability of water (Araus et al., 2003). For mitigating oxidative stress, application of irrigations at vegetative and reproductive growth stages is a sensitive tool for obtaining optimum yields. Irrigation water-regimes at the critical growth stages of wheat minimize severe losses of grain yield as at pre-anthesis (1–30%) and post-anthesis (58–92%) stages (Farooq et al., 2014). Hence, to determine the most critical growth stages of wheat for irrigation management and utilization of available water resources is necessary to maximize crop yield.

The behavior of plants in surviving and producing good yield under limited water stress is called drought tolerance (Turner, 1979). Plants' tolerance against environmental stresses can be increased by the exogenous application of certain growth enhancers like proline, amino acids, ABA, glycine betaine, BAP, silicon, soluble sugars, humic acid, and potassium (Farooq et al., 2009). Appropriate concentrations of these synthetic enhancers could promote the growth of plants and ameliorate water deficit stress by interfering in metabolic and photosynthesis processes through osmotic adjustment, scavenging ROS, increasing enzymatic and non-enzymatic antioxidants and proteins (Bohnert and Jensen, 1996). Exogenous foliar spray of growth enhancers at the critical growth stages of wheat (tillering, booting, heading, milking), is one of the most significant parts which increase antioxidants status against reactive oxygen species under water deficit condition (Yasmeen et al., 2012). Whereas, using these synthetic growth enhancers like BAP or KCl may cause various drastic effects on wheat grain quality, the consumers' health and benefit cost ratio. However, the applications of naturally occurring growth enhancers like moringa leaf extract (MLE) can be environment friendly and economically feasible. Moringa (Moringa oleifera) is a well-known native tree of southern Punjab (Pakistan) and has proved as an excellent growth enhancer containing K, Ca, Fe, amino acids, ascorbates, and growth regulating hormones such as zeatin (Fuglie, 2000). Yasmeen et al. (2012) screened out the positive impact of MLE at various critical growth stages of wheat under saline stress in control conditions (laboratory) and suggested the best application time at tillering and heading. The responses of MLE application to ameliorate drought impacts in wheat at critical growth stages have not been well established yet. Therefore, the present study was conducted to evaluate the performance of MLE as an organically natural plant growth enhancer in comparison with BAP and KCl for improving the productivity of wheat under various irrigation water-regimes at the critical growth stages.

Materials and methods

The experiments were conducted at the Agronomic Experimental Area, Bahauddin Zakariya University Multan (71.43°E, 30.2°N and 122 m above sea level), Pakistan, during the winter seasons of 2013–2014 and 2014–2015. The region is located in semi-arid and sub-tropical climate and data of mean annual temperature. An average rainfall and relative humanity, during the both years of crop growing period is presented in Figure 1. The soil belongs to Sindhlianwali soil series (fine silty, mixed, hyperthermic, sodic haplocambids) in USDA Hap-lic Yermosols in FAO classification. It was characterized after analyzing the samples taken from different locations of the experimental site. Soil was clay loam having ECe 2.42 dS m−1 and pH 8.7, organic matter 0.83–0.88%, total nitrogen 0.05–0.06%, available phosphorus 5.50–5.54 mg kg−1, available potassium 300–303 mg kg−1 and zinc 0.36–0.39 mg kg−1 during both years of trials. The trial comprised two wheat cultivars AARI-11 (drought tolerant) and Millat-11 (drought sensitive; Nawaz et al., 2015). Six irrigation water-regimes were adopted based on the critical growth stages of wheat {Crown Root Initiation (CRI), Tillering (T), Booting (B), and Heading (H) stages} i.e., irrigations applied at CRI+T+B+H (control), irrigations applied at CRI+T+B, irrigations applied at CRI+B, irrigations applied at CRI+H, irrigations applied at T+B and irrigations applied at T+H. The Foliar Application of four growth enhancers i.e. H2O (control), MLE30 (1:30), KCl (2%), BAP (50 mg L−1) @ 500 L ha−1 were applied using garden sprayer (Flat Fan Nozzle). The response of wheat plants to the application of growth enhancers under drought stress or the effect of the growth enhancers on the planted wheat was recorded by measuring growth, yield and biochemical parameters in both the cultivars.

Figure 1.

Figure 1

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Meteorological data for growing period of wheat crop during the years 2013-2014 and 2014-2015.

The procedure described by Yasmeen et al. (2012) for the preparation of moringa leaf extract, was followed. Fresh young leaves were collected from moringa trees grown in the Experimental Area of Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University Multan, Pakistan and stored in a freezer at −80°C. The leaves were crushed through locally available juicer machine; the extract was purified by centrifuging at 8000 rpm for 20 min and diluted 30 times by adding distilled water. Foliar spray of growth enhancers H2O, MLE30, KCl, and BAP was were applied at the tillering and heading stages of the wheat cultivars.

Pre-soaking irrigation of 10 cm depth was applied on the soil to prepare the favorable seedbed conditions for the experiment. After observing the soil at a workable moisture level, it was plowed twice, followed by planting. The seed rate was 125 kg ha−1 and NPK applied at 120-100-62.5 kg ha−1 by using fertilizers urea, single super phosphate and potassium sulfate, respectively. Whole recommended phosphorus, potash and one-third of nitrogen were applied as basal dose and the remaining nitrogen was applied in two splits during the growing period of wheat crop. During both years of trial, slight rains in the growing period occurred but its intensity was not enough to change the soil moisture level under applied water deficit stress condition at the critical growth stages. Intercultural practices and crop protection measures were practiced as per requirement of the crop uniformly for all experimental plots.

Flag leave samples were collected randomly in the morning time (temp. 20 ± 2°C) and stored in polythene bags at −80°C for antioxidants analysis after just 1 week of the last irrigation and foliar application of growth enhancers at the heading stage. The protocol devised by Bradford (1976) was applied to quantify the total soluble proteins (TSP). For determination of endogenous enzymatic and non-enzymatic antioxidants, standard protocols were adopted to measure peroxidase (POD), catalase (CAT) (Chance and Maehly, 1955), superoxide dismutase (SOD) (Giannopolitis and Reis, 1997), ascorbic acid (AsA) (Ainsworth and Gillespie, 2007), and total phenolic contents (TPC) (Waterhouse, 2001). Leaf chlorophyll (“a” and “b”) (Nagata and Yamashita, 1992) and potassium (K+) contents (Rashid, 1986) were determined as per given standard procedures. The number of the productive tillers (m−2) and the number of grains per spike and 1000-grain weight were also recorded. The mature crop was harvested on the 1st and 2nd fortnight of April during the first and second years of the trail respectively, and threshed manually to determine grain yield, biological yield, and harvest index.

The total expenditures of the wheat production were calculated including land rent, seedbed preparation, seed cost, sowing labor, fertilizers, irrigations, weeds preventive measures and harvesting charges of the crops for economic analysis. Gross income was calculated using recent market prices of wheat grains and straw. Net income was obtained by subtracting the total expenditures from gross income and benefit cost-ratio estimated at a ratio of gross income and total expenditures. Data were computed and analyzed statistically using Fisher's analysis of variance technique and LSD test (p < 0.05) to compare differences among the mean values (Steel et al., 1997). Moreover, Microsoft Excel Program 2013 was used for the graphical presentation of meteorological data.

Results

Antioxidants activities

Application of the growth stimulators significantly enhanced the TSP during imposed water deficit stressed levels. However, MLE30 and BAP sprays were more effective in this regard during the both years of study. The maximum TSP was obtained from the foliar application of MLE30 in Millat-11 under irrigation water-regimes of T+B and T+H (Table 1). The effect of exogenously applied stimulators on antioxidants status was found statistically significant (Tables 1, 2). The contents of enzymatic and non-enzymatic antioxidants were increased with the imposition of water deficit stress at the critical growth stages in both wheat cultivars. Among the treatments, MLE30 and BAP application revealed maximum enzymatic activities i.e. SOD, POD, and CAT under irrigated water-regimes of T+B, T+H, and CRI+T respectively, in AARI-11 as compared to Millat-11 during the both years (Tables 1, 2). Irrigation at T+B stages showed a dominant and gradual rise in AsA content in flag leaf of wheat. The maximum contents of AsA (non-enzymatic antioxidants) were observed due to foliar application of MLE30 under all irrigation water-regimes in both cultivars during the both years of trial (Table 2). However, increased content of TPC was obtained under applied irrigations at T+B and T+H stages from applied treatment of MLE30, followed by BAP and KCl in AARI-11 during the both years (Table 2).

Table 1.

Influence of different foliar agents on total soluble protein (TSP), superoxide Dismutase (SOD) and peroxidase (POD) of wheat cultivars under various applied irrigation water-regimes during 2013-2014 (Year-I) and 2014-2015 (Year-II).

Year-I Year-II
Foliar application H2O2 MLE KCl BAP H2O2 MLE30 KCl BAP
Wheat cultivars AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 Mean AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 Mean
TSP (mg g−1) Irrigation water-regimes Control (CRI+T+B+H) 1.20o.q 0.97w 1.34d.h 1.19o.q 1.25k.n 1.20n.q 1.30g.k 1.10uv 1.19d 1.95d.k 1.70r 2.02c.f 1.87k.n 1.98c.h 1.85l.o 1.97c.j 1.79n.q 1.89bc
CRI+T+B 1.31g.k 1.13r.u 1.35c.g 1.16p.s 1.30g.k 1.09uv 1.27i.l 1.10uv 1.21cd 1.91h.m 1.75p.r 2.02c.e 1.83m.p 1.97c.i 1.76o.r 1.94e.l 1.77o.r 1.87cd
CRI+B 1.27i.l 1.13r.u 1.38cd 1.24l.o 1.36c.f 1.16q.t 1.32f.j 1.10t.v 1.24b 1.80n.q 1.72qr 2.02c.e 1.73qr 1.99c.h 1.88j.n 1.99c.h 1.91h.m 1.88b.d
CRI+H 1.31f.j 1.10uv 1.34d.h 1.20n.q 1.31g.k 1.18p.r 1.30h.k 1.12s.u 1.23bc 1.83m.p 1.58s 2.02c.f 1.87k.n 1.92g.l 1.87k.n 1.98c.h 1.77o.r 1.85d
T+B 1.40bc 1.21m.p 1.63a 1.37c.e 1.30g.k 1.26j.m 1.44b 1.34d.h 1.37a 2.05bc 1.87k.n 2.30a 2.04b.d 1.97c.j 1.93f.l 2.12b 2.01c.g 2.03a
T+H 1.27i.l 1.06v 1.35c.g 1.05v 1.32e.i 1.21m.q 1.31f.j 1.24l.o 1.23bc 1.88i.n 1.75p.r 2.05bc 1.91h.m 2.03b.d 1.83m.p 1.99c.h 1.77o.r 1.90b
Mean 1.29c 1.10f 1.40a 1.20d 1.31bc 1.18de 1.32b 1.17e 1.90c 1.73e 2.07a 1.87cd 1.98b 1.85d 1.99b 1.84d
Mean 1.20c 1.30a 1.24b 1.25b 1.81c 1.97a 1.91b 1.92b
LSD 0.05p = W*F*V 0.0557, W 0.0197, F 0.0161, F*V 0.0227 LSD 0.05p = W*F*V 0.0908, W 0.0321, F 0.0262, F*V 0.0371
SOD (IU min−1mg−1 protein) Irrigation water-regimes Control (CRI+T+B+H) 55.25h 29.52m 75.34e 66.68f 62.39f 46.96i 62.89f 56.45gh 56.93d 66.25r.t 40.52x 86.34j.l 77.68mn 73.39n.q 57.96uv 73.89n.p 67.45rs 67.93e
CRI+T+B 44.62i 30.56m 74.71e 74.39e 64.18f 56.54gh 67.08f 64.98f 59.63c 69.32p.r 59.15u 86.27j.l 101.55cd 66.82r.t 61.70tu 75.61no 84.82j.l 75.65d
CRI+B 46.32i 36.15kl 63.27f 78.55e 43.82ij 38.70jk 52.61h 61.82fg 52.65e 62.62s.u 48.56w 92.7f.i 92.39g.i 82.18lm 74.54n.p 85.08j.l 82.98k.m 77.63c
CRI+H 42.53ij 31.23lm 86.97d 75.10e 47.11i 30.29m 66.10f 73.87e 56.65d 62.53s.u 51.23w 106.9b 95.10e.g 67.11rs 50.29w 86.10j.l 93.87e.h 76.65cd
T+B 99.75b 52.89h 125.59a 85.10d 94.15c 46.65i 104.34b 74.70e 85.39a 106.75bc 59.89u 132.59a 92.10g.i 101.15d 53.65vw 111.34b 81.70lm 92.39a
T+H 63.90f 44.24i 74.53e 87.17d 64.53f 46.67i 73.81e 64.21f 64.88b 87.90i.k 68.24qr 98.53de 111.17b 88.53h.j 70.67o.r 97.81d.f 88.21i.k 88.88b
Mean 58.72f 37.43h 83.40a 77.832 b 62.69e 44.30g 71.13c 66.00d 75.89f 54.60h 100.57a 95.00b 79.86e 61.47g 88.30c 83.17d
Mean 48.07d 80.61a 53.50c 68.57b 65.24d 97.78a 70.66c 85.73b
LSD 0.05p = W*F*V5.3867, W 1.9045, F 1.5550, F*V 2.1991 LSD 0.05p = W*F*V 5.0811, W 1.86001, F 1.4690, F*V 2.20470
POD (mmol min−1 mg protein−1) Irrigation water-regimes Control (CRI+T+B+H) 22.65h.k 17.02z.b 27.67b 22.30j.l 24.26fg 21.52l.o 25.55cd 20.25q.s 22.65b 28.26lm 24.25u 31.67de 26.30p.s 26.65n.q 25.52st 29.55h.k 21.02 w 26.65d
CRI+T+B 21.51l.o 18.01w.y 24.51ef 19.84r.t 21.34m.p 17.268y.a 22.91h.j 18.05w.y 20.43d 26.34p.s 23.05v 29.51h.k 24.84tu 26.51o.r 22.26v 27.91lm 23.01v 25.43e
CRI+B 20.06rs 17.44x.a 22.46i.l 20.52p.r 21.18n.q 17.93w.z 20.66o.r 17.82x.z 19.76e 26.32p.s 24.34u 29.36i.k 27.42m.o 27.56mn 24.72tu 28.08lm 24.83tu 26.58d
CRI+H 22.18j.m 18.37v.x 24.11fg 21.58l.o 22.65h.k 19.48s.u 22.92h.j 18.88u.w 21.27c 30.45f.h 26.17q.s 31.91d 29.38i.k 29.98g.i 26.68n.q 30.72e.g 27.28m.p 29.07b
T+B 25.28de 20.69o.r 31.58a 24.23fg 23.52gh 21.69k.n 26.27c 23.41g.i 24.59a 31.52de 29.69h.j 39.58a 32.23d 33.28c 28.69kl 34.27b 31.41d.f 32.59a
T+H 19.05t.v 14.34c 22.41j.l 16.26b 19.93r.t 16.64ab 19.84r.t 17.46x.a 18.24f 28.83j.l 23.24v 31.31d.f 25.16tu 27.95lm 25.54r.t 28.74j.l 26.36p.s 27.14c
Mean 21.79c 17.65f 25.46a 20.79d 22.15c 19.09e 23.03b 19.31e 28.62c 25.12f 32.22a 27.56d 28.65c 25.57e 29.88b 25.65e
Mean 19.72d 19.72d 19.72d 19.72d 26.87c 29.89a 27.11c 27.77b
LSD 0.05p = W*F*V 0.9619, W 0.3401, F 0.2777, F*V 0.3927 LSD 0.05p = W*F*V 0.9875, W 0.3491, F 0.2851, F*V 0.4032
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Means not sharing the same letters in a group differ significantly at 5% probability level. W, Irrigation Water-regimes; F, Foliar agents; V, Wheat cultivars.

Table 2.

Influence of different foliar agents on catalase (CAT), ascorbic acid (AsA) and total phenolic contents (TPC) of wheat cultivars under various applied irrigation water-regimes during 2013-2014 (Year-I) and 2014-2015 (Year-II).

Year-I Year-II
Foliar application H2O2 MLE KCl BAP H2O2 MLE30 KCl BAP
Wheat cultivars AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 Mean AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 Mean
CAT (μ mol min−1 mg protein−1) Irrigation water-regimes Control (CRI+T+B+H) 8.20u 9.11r.t 10.89q 9.55 8.75s.u 8.91r.u 9.42rs 8.30u 9.14f 16.60lm 9.03w 18.42k 10.31uv 15.18no 8.85wx 16.62lm 9.55vw 13.07d
CRI+T+B 13.60no 8.66tu 14.64m 9.24r.t 13.51no 8.26u 13.70n 8.54tu 11.27e 10.95tu 6.88yz 13.99pq 7.80xy 11.63st 6.15za 12.42rs 5.77a 9.45e
CRI+B 16.80l 14.09mn 20.25h 16.72l 19.28ij 14.57m 18.67jk 14.73m 16.89d 19.15k 12.34rs 22.79hi 14.82n.p 21.79ij 12.78r 21.09j 13.03qr 17.22c
CRI+H 21.61g 17.12l 23.69f 19.92hi 22.05g 18.65jk 22.07g 18.04k 20.39b 24.79ef 13.12qr 26.80d 14.94n.p 25.69e 14.89n.p 25.66e 15.38no 20.16b
T+B 27.17c 21.36g 33.69a 24.81e 26.61cd 21.52g 29.68b 23.88f 26.09a 30.40c 21.05j 37.44a 24.47fg 29.60c 21.20j 33.00b 23.54gh 27.59a
T+H 24.00f 10.98q 25.96d 12.14p 24.87e 12.45p 24.84e 12.87op 18.51c 23.72f.h 14.34op 25.85de 16.88l 24.15fg 15.67mn 24.16fg 15.21no 20.00b
Mean 18.56d 13.55h 21.52a 15.40e 19.18c 14.06g 19.73b 14.39f 20.94c 12.79g 24.21a 14.87d 21.34c 13.26f 22.16b 13.75e
Mean 16.06d 18.46a 16.62c 17.06b 16.86d 19.54a 17.30c 17.95b
LSD 0.05p = W*F*V 0.7493, W 0.2649, F 0.2163, F*V 0.3059 LSD 0.05p = W*F*V 1.0834, W 0.3830, F 0.3128, F*V 0.4423
AsA (m. mole g−1) Irrigation water-regimes Control (CRI+T+B+H) 31.56t 34.20s 55.76p 38.96r 31.76t 34.26s 38.26r 38.56r 37.92f 37.36z 40.00y 48.46v 45.66w 39.66y 42.16x 38.80yz 38.53yz 41.33e
CRI+T+B 65.40ij 55.76p 69.46f 57.40n 65.56ij 55.90op 72.26b.d 57.10no 62.35e 71.20m.o 61.56rs 76.16f.h 64.10q 73.46i.k 63.80q 72.80j.m 57.66t 67.59d
CRI+B 71.33c.e 58.70m 71.60b.e 65.20j 71.26de 58.90lm 71.46c.e 60.10l 66.07b 71.56mn 64.70q 79.26cd 69.80o 75.10g.i 70.23no 71.86k.n 63.30qr 70.72b
CRI+H 67.56gh 49.90q 71.60b.e 67.83g 69.70f 50.10q 71.40c.e 66.56hi 64.33d 73.36i.l 55.70u 78.30c.e 74.53h.j 77.60d.f 58.00t 71.93k.n 67.06p 69.56c
T+B 76.33a 70.50ef 77.06a 72.80b 76.26a 71.20de 76.46a 71.16de 73.97a 82.13b 76.30fg 83.76ab 79.50c 84.16a 79.10cd 77.00ef 71.66l.n 79.20a
T+H 65.76ij 58.90lm 72.56bc 63.10k 67.20gh 62.33k 71.33c.e 62.76k 65.49c 77.13ef 64.50q 78.30c.e 71.90k.n 79.16cd 66.80p 72.00k.m 60.66s 71.30b
Mean 62.99d 54.66h 69.67a 60.88e 63.62c 55.45g 66.86b 59.37f 68.79c 60.46f 74.04a 67.58d 71.52b 63.35e 67.40d 59.81f
Mean 58.82d 65.28a 59.53c 63.12b 64.62c 70.81a 67.43b 63.60d
LSD 0.05p = W*F*V 1.2371, W 0.4374, F 0.3571, F*V 0.5050 LSD 0.05p = W*F*V 1.7452, W 0.6170, F 0.5038, F*V 0.7125
TPC (mg g−1) Irrigation water-regimes Control (CRI+T+B+H) 1.80st 1.29uv 2.91l.n 2.43o.q 1.87rs 1.40u 2.73m.o 2.15qr 2.07d 2.58k.p 1.47qr 3.02h.n 2.32l.q 2.01n.r 1.29r 2.84i.n 2.04n.r 2.20c
CRI+T+B 1.50tu 1.01v 3.30i.k 2.70m.o 1.47tu 0.98v 2.98k.m 2.35pq 2.04d 1.80o.r 1.22r 3.48e.k 2.73j.o 1.65p.r 1.19r 2.78j.o 2.35l.q 2.15c
CRI+B 3.30i.k 2.56op 4.07de 3.67fg 3.43g.i 2.98k.m 3.79ef 3.31h.k 3.39c 3.12h.l 3.55d.k 4.29c.g 3.83d.i 3.10h.m 3.97c.h 3.32f.l 4.30b.f 3.68b
CRI+H 4.40cd 3.64f.h 4.45bc 3.61f.i 3.63f.i 2.57n.p 3.36g.j 3.47f.i 3.64b 3.66d.j 3.10h.m 4.54a.d 3.65d.j 3.13h.l 2.41l.q 3.45e.k 3.51d.k 3.43b
T+B 3.61f.i 3.03j.m 4.89a 4.42c 3.68fg 3.08j.l 4.80a 4.22cd 3.97a 4.27c.g 3.26g.l 5.46a 3.84d.i 4.34b.f 3.31f.l 5.33ab 4.45a.e 4.28a
T+H 4.43c 2.91l.n 4.78ab 3.44g.i 3.47f.i 1.96rs 4.84a 3.31h.k 3.64b 3.71d.j 3.04h.n 4.89 a.c 2.87i.n 3.58d.k 2.09m.r 4.95a.c 2.97h.n 3.51b
Mean 3.17d 2.41f 4.06a 3.38c 2.93e 2.16g 3.75b 3.14d 3.19c 2.61de 4.28a 3.21c 2.97cd 2.38e 3.78b 3.27c
Mean 2.79c 3.72a 2.54d 3.44b 2.90b 3.74a 2.67b 3.53a
LSD 0.05p = W*F*V 0.3364, W 0.1189, F 0.0971, F*V 0.1373 LSD 0.05p = W*F*V 1.0308, W 0.3644, F 0.2976, F*V 0.4208
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Means not sharing the same letters in a group differ significantly at 5% probability level. W, Irrigation Water-regimes; F, Foliar agents; V, Wheat cultivars.

Leaf chlorophyll contents

Chlorophyll contents “a” and “b” were found significantly higher, due to foliar application of MLE30 and BAP under applied irrigation regimes of control, T+ B and T+H stages in AARI-11 during the both years of study (Table 3). The results also illustrated that the chlorophyll contents “a” and “b” decreased in Millat-11 under all irrigation water-regimes but due to the foliar application of MLE30 and BAP, their levels were maintained (Table 3).

Table 3.

Influence of different foliar agents on chlorophyll “a & b” and K+ contents of wheat cultivars under various applied irrigation water-regimes during 2013-2014 (Year-I) and 2014-2015 (Year-II).

Year-I Year-II
Foliar application H2O2 MLE KCl BAP H2O2 MLE30 KCl BAP
Wheat cultivars AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 Mean AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 Mean
Chlorophyll “a” (mg g−1) Irrigation water-regimes Control (CRI+T+B+H) 1.07m.q 0.85q.s 2.53a 2.15cd 2.20b.d 0.80q.s 2.33a.c 1.07m.q 1.62a 2.53a.c 1.13n.r 2.63ab 2.03de 1.76e.h 1.73e.i 2.27cd 1.66g.j 1.97a
CRI+T+B 1.07m.q 0.83q.s 1.57g.k 1.91d.f 2.13cd 0.89q.s 2.12cd 0.87q.s 1.42bc 1.57g.l 0.95q.t 1.68f.j 1.66g.j 1.18m.r 0.88r.t 1.42i.n 0.93r.t 1.28d
CRI+B 0.91p.r 1.00n.q 1.47h.l 1.46h.l 1.19l.p 1.55g.k 1.39i.l 1.69e.i 1.33cd 1.27l.q 1.56g.l 1.56g.l 1.48h.m 0.99o.s 1.02o.s 1.48h.m 1.70f.j 1.38cd
CRI+H 0.39t 1.20l.p 0.61st 2.45ab 0.87q.s 1.29k.n 1.21l.o 1.63f.j 1.21e 0.97p.s 1.48h.m 0.72s.u 2.64ab 0.49u 1.39j.n 1.32k.o 1.82e.g 1.35cd
T+B 1.21l.o 1.38j.l 2.08cd 1.35j.m 1.97de 0.79q.s 1.72e.h 1.31k.m 1.48b 2.41bc 0.91r.t 2.74a 2.26cd 1.29l.p 0.97p.s 2.54a.c 1.19m.r 1.79b
T+H 0.40t 0.98o.q 2.35a.c 1.44h.l 1.42i.l 0.64r.t 1.78e.g 0.89q.s 1.24de 1.64g.k 0.75s.u 2.57a.c 1.55g.l 0.62tu 1.10n.r 2.00d.f 1.00o.s 1.40c
Mean 0.84e 1.04d 1.77a 1.79a 1.63b 0.99d 1.76a 1.24c 1.73c 1.13e 1.98a 1.93ab 1.05e 1.18e 1.84bc 1.38d
Mean 0.94d 1.78a 1.31c 1.50b 1.43c 1.96a 1.12d 1.61b
LSD 0.05p = W*F*V 0.2950, W 0.1043, F 0.0852, F*V 0.1204 LSD 0.05p = W*F*V 0.3309, W 0.1170, F 0.0955, F*V 0.1351
Chlorophyll “b” (mg g−1) Irrigation water-regimes Control (CRI+T+B+H) 0.21q 0.86c 0.61u 0.89b 0.59x 0.72k 0.49e 0.70n 0.63a 1.03b 0.47st 1.06a 0.87f 0.89e 0.85fg 0.87f 0.75i 0.85a
CRI+T+B 0.60w 0.52d 0.72j 0.70m 0.52c 0.61t 0.48g 0.56z 0.59c 0.72j 0.61no 0.84g 0.79h 0.64m 0.70k 0.60n.p 0.65lm 0.69b
CRI+B 0.37l 0.57y 0.73i 0.65q 0.72l 0.30n 0.74f 0.32m 0.55d 0.55q 0.64lm 0.91d 0.72j 0.90de 0.37v 0.76i 0.39v 0.65c
CRI+H 0.46h 0.20r 0.80e 0.60v 0.61v 0.45i 0.65p 0.44j 0.53e 0.47st 0.21y 0.62n 0.61no 0.51r 0.46tu 0.59op 0.45u 0.49e
T+B 0.53b 0.25p 0.90a 0.68o 0.82d 0.54a 0.74h 0.44k 0.61b 0.30w 0.55q 0.95c 0.84g 0.59p 0.70k 0.49s 0.76i 0.63d
T+H 0.27o 0.09s 0.74g 0.64s 0.72j 0.49f 0.65r 0.59x 0.52f 0.28x 0.11z 0.75i 0.66l 0.73j 0.31w 0.66lm 0.21y 0.46f
Mean 0.41h 0.41g 0.75a 0.69b 0.66c 0.52e 0.62d 0.51f 0.56e 0.43g 0.85a 0.75b 0.71c 0.56e 0.66d 0.53f
Mean 0.41d 0.72a 0.59b 0.57c 0.49d 0.80a 0.64b 0.60c
LSD 0.05p = W*F*V 0.173, W 0.164, F 0.422, F*V 0.0153 LSD 0.05p = W*F*V 0.0193, W 0.1112, F 0.232, F*V 0.1209
K+ contents (mg g−1) Irrigation water-regimes Control (CRI+T+B+H) 2.00d 1.90e 2.33a 2.20b 2.10c 1.80f 2.20b 2.10c 2.07a 2.43c.g 2.37c.i 3.01a 2.59b.d 2.46c.g 2.24e.l 2.51c.e 2.44c.g 2.50a
CRI+T+B 1.80f 1.10m 2.20b 1.40j 1.60h 1.30k 1.70g 1.40j 1.56c 2.24e.l 2.14g.o 2.61b.d 2.39c.h 2.21e.n 2.14f.o 2.64bc 2.33c.j 2.34b
CRI+B 0.60q 0.60q 1.10m 1.00n 0.80p 0.80p 0.90o 0.90o 0.83f 1.57t.v 1.50uv 1.72q.v 1.59s.v 1.48uv 1.39v 1.58s.v 1.50uv 1.54f
CRI+H 1.10m 1.10m 1.20l 1.40j 1.00n 1.10m 1.10m 1.10m 1.13e 1.70r.v 1.70r.v 1.89m.t 1.99j.r 1.66r.v 1.84o.t 1.70r.v 1.78p.u 1.78e
T+B 1.60h 1.50i 2.20b 1.80f 1.70g 1.60h 2.00d 1.70g 1.76b 2.48c.f 1.76p.u 2.87ab 2.07h.p 2.28d.k 1.97k.r 2.22e.m 2.05i.q 2.21c
T+H 1.30k 1.20l 1.40j 1.30k 1.20l 1.10m 1.30k 1.20l 1.25d 1.95k.r 1.81o.u 2.08h.p 1.91l.s 1.87n.t 1.71q.v 1.96k.r 1.96k.r 1.91d
Mean 1.40c 1.23e 1.73a 1.51b 1.40c 1.28d 1.53b 1.40c 2.06b 1.88c 2.36a 2.09b 1.99bc 1.88c 2.10b 2.01bc
Mean 1.31c 1.62a 1.34c 1.46b 1.97bc 2.23a 1.94c 2.05b
LSD 0.05p = W*F*V 0.0969, W 0.0343, F 0.0280, F*V 0.0396 LSD 0.05p = W*F*V 0.3404, W 0.1204, F 0.0983, F*V 0.1390
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Means not sharing the same letters in a group differ significantly at 5% probability level. W, Irrigation Water-regimes; F, Foliar agents; V, Wheat cultivars.

Leaf K+ content

The MLE30 application increased leaf K+ content under imposed irrigation water-regimes, but the maximum leaf K+ content was observed in AARI-11 plants under the applied irrigation water-regimes of control, CRI+T+B and T+B respectively, in the both years. The least K+ contents were observed under the irrigation water-regimes applied at CRI+T, CRI+B, and CRI+H stages in both cultivars during the both years of trial (Table 3).

Yield and yield components

Foliar applications, irrigation water-regimes and wheat cultivars significantly affected the number of fertile tillers (Table 4). Results demonstrated that the application of MLE30 and BAP with irrigation water-regimes of CRI+T+B+H, CRI+T+B, and T+B resulted in the maximum fertile tillers in AARI-11 during the both growing years. The minimum number of fertile tillers was observed when irrigations were applied at CRI+B and T+H stages in both cultivars during the year-I but fertile tillers increased by the application of growth stimulators during the year-II, even though the irrigations were applied at CRI+B and T+H stages (Table 4). Results revealed that the number of grains per spike with the irrigation water-regimes at control, CRI+T+B and T+B stages were non-significant in both cultivars. Among the foliar sprays, performance of MLE30 was better than BAP, KCl, and H2O and produced the maximum number of grains per spike in both cultivars under all irrigation water-regimes (Table 4). Foliar growth agents under the applied irrigations at CRI+T+B+H, T+B, T+H critical growth stages in the studied wheat cultivars significantly affected yield components (Table 5). The results depicted that 1000-grain weight in AARI-11 was the maximum under the applied irrigation water-regimes of control, followed by T+B and T+H especially by MLE30 treatment during the both years of study. Yield parameters i.e. grain yield, biological yield and harvest index clearly demonstrated significant results among the wheat cultivars grown under various irrigation water-regimes (Table 5). Among the growth stimulators, MLE30 and BAP applied to AARI-11, resulted in the maximum grain yield and harvest index when the irrigations were applied at CRI+T+B+H, CRI+T+B, and T+B stages during the both years. Harvest index of wheat cultivars during the both years of trial at the applied irrigation water-regimes of control and T+B was the maximum due to the application of MLE30 (Table 5).

Table 4.

Influence of different foliar agents on fertile tillers (m−2), grain Spike−1 and 1000 grain weight (g) of wheat cultivars under applied irrigation water-regimes during 2013-2014 (Year-I) and 2014-2015 (Year-II).

Year-I Year-II
Foliar application H2O2 MLE KCl BAP H2O2 MLE30 KCl BAP
Wheat cultivars AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 Mean AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 Mean
Fertile tillers (m−2) Irrigation water-regimes Control (CRI+T+B+H) 300f.h 342a.c 348ab 351a 309e.g 336a.c 343a.c 330b.d 332a 270g.j 332a.e 352a 355a 290f.i 323a.f 335a.d 336a.d 324a
CRI+T+B 330b.d 312d.f 342a.c 333a.c 334a.c 297f.h 342a.c 308e.g 325b 312c.f 305d.g 331a.e 337a.d 337a.d 268ij 348ab 314b.f 319a
CRI+B 289gh 290gh 302f.h 287h 295f.h 301f.h 295f.h 292gh 294c 324a.f 241j.l 344a.c 242j.l 322a.f 232k.m 329a.e 253jk 286b
CRI+H 202j.l 209j 240i 196j.l 201j.l 201j.l 200j.l 197j.l 206d 204m.p 211l.o 224k.n 200m.p 204m.p 199m.p 206m.p 203m.p 206c
T+B 339a.c 239i 340a.c 238i 329b.d 248i 323c.e 247i 288c 291f.i 292f.i 306d.f 291f.i 298e.i 304d.h 270h.j 297e.i 293b
T+H 188kl 184l 205jk 188kl 191j.l 187kl 188kl 184l 189e 190n.q 186o.q 209l.p 193n.q 193n.q 174pq 194n.q 159q 187d
Mean 275b 263c 296a 265c 276b 261c 282b 259c 265c 261cd 294a 269bc 274bc 250d 280ab 260cd
Mean 269b 281a 269b 271b 263b 282a 262b 270b
LSD 0.05p = W*F*V 20.179, W 7.1343, F 5.8251, F*V 8.2379 LSD 0.05p = W*F*V 35.170, W 12.434, F 10.153, F*V 14.358
Grain spike−1 Irrigation water-regimes Control (CRI+T+B+H) 36v 37t 50a 45d 41k 37t 46c 40n 41b 42kl 43jk 55a 51bc 47fg 43jk 47f.h 45g.i 46b
CRI+T+B 42g 36v 47b 45d 44e 37t 46c 40n 42a 48ef 41lm 52b 50cd 49de 42kl 51bc 45hi 47a
CRI+B 34z 39o 46c 42hi 38qr 42hi 42hi 39o 40c 44ij 39no 48ef 48ef 45hi 41lm 46gh 43jk 44d
CRI+H 31b 39p 42g 41k 36w 40m 42i 41l 39d 37p 44ij 48ef 47fg 41lm 46gh 47fg 46gh 44d
T+B 38q 34a 42f 42h 40n 35x 41k 38r 39e 39no 44ij 51bc 47fg 43jk 47fg 47fg 44ij 45c
T+H 37u 37s 42f 39o 35y 37t 42j 38p 38f 38op 41l.n 47fg 41lm 39no 40m.o 46gh 41k.m 41e
Mean 36h 37g 45a 42c 39e 38f 43b 39d 41e 42e 50a 47b 44c 43d 47b 44c
Mean 37d 44a 38c 41b 42d 49a 43c 46b
LSD 0.05p = W*F*V 0.1351, W 0.0478, F 0.0390, F*V 0.0552 LSD 0.05p = W*F*V 1.7024, W 0.6019, F 0.4914, F*V 0.6950
1000-Grain weight (g) Irrigation water-regimes Control (CRI+T+B+H) 37.30l 37.86j 51.60a 43.20c 40.40f 37.50k 43.00d 39.70g 41.32a 39.16j 39.76h 48.76a 41.06d 41.66c 38.76k 44.36b 40.36g 41.74a
CRI+T+B 33.06v 35.66p 43.76b 37.16m 35.56q 35.06r 35.96o 36.26n 36.56b 29.86I 30.66F 34.46u 36.56q 33.86x 29.26J 30.56G 35.40s 32.58c
CRI+B 31.36b 30.46d 32.76x 34.36s 29.76f 30.76c 31.46a 32.46z 31.67d 33.26Z 32.36B 32.80A 33.80y 31.00E 32.00C 29.90I 31.50D 32.07d
CRI+H 23.80o 24.80m 30.16e 32.90w 26.26k 24.80m 27.16j 26.30k 27.02f 25.66q 26.66O 28.50K 30.06H 27.50M 26.06P 27.30N 27.66L 27.42f
T+B 28.00i 28.76g 33.40u 39.46h 32.60y 28.06h 33.10v 34.06t 32.18c 34.96t 37.56n 40.90e 37.66M 36.80p 36.30r 37.36o 34.30w 36.98b
T+H 32.46z 23.66p 42.46e 24.96l 37.16m 22.16q 39.36i 24.26n 30.81e 34.36v 25.56r 40.70f 25.66Q 38.36l 23.40S 39.56i 22.10T 31.21e
Mean 31.00f 30.20g 39.02a 35.34b 33.62d 29.72h 35.01c 32.17e 32.88e 32.10f 37.68a 34.13d 34.86b 30.96h 34.84c 31.88g
Mean 30.60d 37.18a 31.67c 33.59b 32.49d 35.91a 32.91c 33.36b
LSD 0.05p = W*F*V 0.0446, W 0.0158, F 0.0129, F*V 0.0182 LSD 0.05p = W*F*V 0.0452, W 0.0160, F 0.0131, F*V 0.0185
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Means not sharing the same letters in a group differ significantly at 5% probability level. W, Irrigation Water-regimes; F, Foliar agents; V, Wheat cultivars.

Table 5.

Influence of different Foliar agents on grain yield (t/ha), biological yield (t/ha) and harvest index (%) of wheat cultivars under applied irrigation water-regimes during 2013-2014 (Year-I) and 2014-2015 (Year-II).

Year-I Year-II
Foliar application H2O2 MLE KCl BAP H2O2 MLE30 KCl BAP
Wheat cultivars AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 Mean AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 AARI-11 Millat-11 Mean
Grain yield (t/ha) Irrigation water-regimes Control (CRI+T+B+H) 4.55h.l 4.07n.p 5.65a 4.41j.n 4.86e.h 4.29k.o 4.92d.g 4.31j.o 4.63a 4.88f.k 4.25p.r 5.84a 5.40bc 4.88f.k 4.38n.r 5.37b.d 5.28b.e 5.04a
CRI+T+B 4.38j.n 2.08v 5.47ab 4.62g.k 5.22b.d 3.14tu 5.28bc 4.18m.p 4.29c 4.55k.q 5.18c.f 5.19c.f 4.41m.r 4.56k.q 4.90f.k 5.00e.i 5.37b.d 4.89b
CRI+B 4.48j.m 2.20v 4.97c.f 3.93pq 4.50i.m 2.94u 4.58g.k 3.88p.r 3.93e 4.68h.n 4.61j.p 5.40bc 5.11c.g 4.63i.o 3.42u 4.95e.j 4.08rs 4.61c
CRI+H 4.40j.n 3.14tu 5.17b.e 4.62f.k 3.41st 4.20m.p 4.65f.j 4.57g.k 4.27c 4.51l.q 4.41m.r 4.76g.m 4.85f.l 4.41m.r 3.67tu 4.58k.q 4.58k.q 4.47d
T+B 4.59g.k 3.43st 5.25b.d 4.44j.m 5.09c.e 3.55rs 5.10c.e 4.32j.o 4.47b 4.68h.n 4.11rs 5.63ab 5.40bc 4.41m.r 4.38n.r 5.12c.g 5.37b.d 4.89b
T+H 4.01o.q 3.69q.s 4.83e.i 4.46j.m 4.21l.p 3.44st 4.34j.o 4.01o.q 4.12d 4.21qr 4.27o.r 5.03d.h 5.17c.f 3.79st 4.78g.l 5.06c.g 4.60j.p 4.61c
Mean 4.40d 3.10g 5.22a 4.41cd 4.55c 3.59f 4.81b 4.21e 4.59d 4.47d 5.31a 5.06b 4.45d 4.26e 5.01bc 4.88c 4.59d
Mean 3.75d 4.82a 4.07c 4.51b 4.53c 5.18a 4.35d 4.94b
LSD 0.05p = W*F*V 0.3470, W 0.1227, F 0.1002, F*V 0.1416 LSD 0.05p = W*F*V 0.3659, W 0.1294, F 0.1056, F*V 0.1494
Biological yield (t/ha) Irrigation water-regimes Control (CRI+T+B+H) 12.03f 9.93s 13.33a 11.33i 12.83d 9.33x 12.96c 10.66n 11.55a 13.42b.d 11.69g.m 14.47a 12.14f.i 13.30b.e 11.81g.k 13.83ab 10.84l.r 12.69a
CRI+T+B 11.16j 7.96E 11.66g 10.03r 11.13j 8.53C 11.36i 9.16z 10.12d 12.60d.g 10.19q.v 13.58a.c 11.77g.l 12.77c.f 11.82g.k 12.80c.f 11.41h.o 12.12b
CRI+B 10.20q 8.86A 11.66g 11.13j 11.60h 9.13z 11.16j 9.73u 10.43c 9.91s.v 8.27w 12.80c.f 10.93k.r 10.79m.s 9.80t.v 11.17j.p 10.40p.u 10.51e
CRI+H 9.80t 7.63G 10.16q 10.06r 9.83t 7.83F 9.90s 8.76B 9.25f 11.51h.m 10.10r.v 13.40b.d 11.43h.n 11.36i.o 10.48o.t 10.56n.t 11.16j.p 11.25cd
T+B 10.73m 8.03D 13.03b 11.16j 11.03k 9.13z 12.46e 9.63v 10.65b 11.07j.q 10.19q.v 13.81ab 11.89f.j 12.11f.i 10.54n.t 12.21f.i 10.79m.s 11.57c
T+H 10.33p 7.63G 10.96l 9.46w 10.43o 8.86A 10.73m 9.23y 9.70e 10.90k.r 9.47uv 13.54bc 12.33f.h 11.36i.o 9.45v 12.45e.g 10.15q.v 11.21d
Mean 10.71d 8.34h 11.80a 10.53e 11.14c 8.80g 11.43b 9.53f 11.57c 9.98e 13.60a 11.75c 11.95bc 10.65d 12.17b 10.79d
Mean 9.52d 11.16a 9.97c 10.48b 10.78c 12.67a 11.30b 11.48b
LSD 0.05p = W*F*V 0.0500, W 0.0177, F 0.0144, F*V 0.0204 LSD 0.05p = W*F*V 0.9298, W 0.3287, F 0.2684, F*V 0.3796
Harvest index (%) Irrigation water-regimes Control (CRI+T+B+H) 37.11f.m 40.51a.g 41.93a 41.78ab 33.17n.s 40.62a.f 41.00a.e 37.84c.l 39.24a 41.55a.e 33.67n.p 45.11ab 40.06c.j 42.02a.d 33.75n.p 41.86a.d 37.41f.n 39.43a
CRI+T+B 34.69l.r 39.05a.j 38.08b.l 31.90p.s 34.86k.q 39.75a.h 37.46d.m 41.22a.d 37.13b 38.44d.m 31.14op 44.08a.c 40.50c.i 30.15pq 40.13c.j 38.65d.m 40.99c.f 38.01ab
CRI+B 39.89a.h 32.87o.s 41.53a.c 35.53j.p 35.81i.o 27.77t 39.62a.i 31.58q.t 35.57c 34.17n.p 34.80m.o 39.05d.l 39.78d.k 36.54h.n 36.32j.n 35.52l.n 36.34j.n 36.56b
CRI+H 37.71d.m 29.72st 38.58a.k 34.42l.r 36.78g.n 30.92r.t 37.90c.l 33.24n.s 34.91c 34.79m.o 20.47r 41.09b.f 39.29d.l 39.29d.l 26.60q 40.61c.h 36.68g.n 34.85c
T+B 35.64j.p 37.23e.m 39.64a.h 38.06b.l 36.29h.o 36.15h.o 37.54d.m 36.40h.o 37.12b 40.78c.g 26.89q 45.20a 36.07j.n 41.92a.d 30.16pq 41.00b.f 37.38f.n 37.42b
T+H 36.98f.n 32.67o.s 40.25a.g 37.59d.m 34.81k.q 33.93m.r 38.02b.l 35.17k.q 36.18bc 36.81g.n 34.82m.o 39.18d.l 36.20j.n 37.43f.n 36.45i.n 35.68k.n 37.51f.n 36.76b
Mean 37.00b 35.34cd 40.00a 36.55bc 35.28cd 34.86d 38.59a 35.91b.d 37.76b 30.30d 42.28a 38.65b 37.89b 33.90c 38.89b 37.71b
Mean 36.17bc 38.27a 35.07c 37.25ab 34.03d 40.47a 35.90c 38.30b
LSD 0.05p = W*F*V 3.8185, W 1.3500, F 1.1023, F*V 1.5589 LSD 0.05p = W*F*V 4.1122, W 1.4539, F 1.1871, F*V 1.6788
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Means not sharing the same letters in a group differ significantly at 5% probability level. W, Irrigation Water-regimes; F, Foliar agents; V, Wheat cultivars.

Benefit cost ratio

Economic analysis showed that the MLE30 foliar application was comparatively the most cost effective technology to obtain the maximum benefit cost ratio (BCR) with irrigation water-regimes of CRI+T and T+B after control (Table 6).

Table 6.

Economic analysis (average of both cultivars) for the impact of foliar spray under various irrigation water-regimes at the critical growth stages of wheat.

Treatment Total expenditure (US$ ha−1) Gross income (US$ ha−1) Net income (US$ ha−1) Benefit cost ratio
2013-14 2014-15 2013-14 2014-15 2013-14 2014-15 2013-14 2014-15
H2O foliar spray Control 629.27 629.27 1282.33 1046.57 653.06 417.29 2.04 1.66
CRI+T+B 615.64 615.64 1129.78 1124.85 514.14 509.21 1.84 1.83
CRI+B 602.00 602.00 989.42 928.70 387.42 326.70 1.64 1.54
CRI+H 602.00 602.00 891.71 1074.46 289.71 472.46 1.48 1.78
T+B 602.00 602.00 886.56 1075.68 284.56 473.68 1.47 1.79
T+H 602.00 602.00 1033.09 1038.68 431.09 436.68 1.72 1.73
MLE30 foliar spray Control 633.55 606.55 997.95 1367.99 391.40 761.45 1.65 2.26
CRI+T+B 620.18 620.18 1183.97 1282.92 563.78 662.74 1.91 2.07
CRI+B 606.55 606.55 995.79 1006.53 389.24 399.98 1.64 1.66
CRI+H 606.82 633.82 1479.73 1311.78 845.92 677.96 2.33 2.07
T+B 606.55 606.55 1172.01 1266.43 565.46 659.88 1.93 2.09
T+H 606.55 606.55 1019.57 1249.79 413.02 643.25 1.68 2.06
KCl foliar spray Control 642.91 642.91 1219.56 1160.59 576.65 517.68 1.90 1.81
CRI+T+B 629.27 629.27 969.19 1160.91 339.92 531.64 1.54 1.84
CRI+B 615.64 615.64 1048.31 903.26 432.67 287.62 1.70 1.47
CRI+H 615.64 615.64 731.44 1036.67 115.81 421.03 1.19 1.68
T+B 615.64 615.64 793.32 1038.09 177.68 422.45 1.29 1.69
T+H 615.64 615.64 930.64 1171.35 315.00 555.72 1.51 1.90
BAP foliar spray Control 670.18 670.18 1445.62 1018.51 775.44 348.33 2.16 1.52
CRI+T+B 656.55 656.55 1130.94 1297.51 474.40 640.96 1.72 1.98
CRI+B 642.91 642.91 1025.59 940.16 382.68 297.25 1.60 1.46
CRI+H 642.91 642.91 892.51 981.87 249.61 338.96 1.39 1.53
T+B 642.91 642.91 977.00 1253.91 334.09 611.00 1.52 1.95
T+H 642.91 642.91 1041.61 1300.17 398.70 657.26 1.62 2.02
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Discussion

Oxidative stress under water deficit conditions is characterized as an imbalance between production of ROS and quenching activity of antioxidant system which possesses a serious threat to plant cellular membranes and other cellular organelles like proteins, DNA, etc. (White et al., 1993). The ability of plant to scavenge toxic/active ionic forms of oxygen radicles has seemed to be an important consideration of its tolerance to environmental stresses including water deficit stress. Plant antioxidants defense system including enzymatic (SOD, CAT, POD) and non-enzymatic (AsA, TPC) ones has been proved a possible protective measure against oxidative damages by inhibiting release of ROS (Mittler, 2002). The present study demonstrated that increased contents of antioxidants (enzymatic and non-enzymatic) by foliar application of growth enhancers especially MLE30 and BAP at various sensitive growth stages of wheat cultivars under water deficit conditions, is the most effective strategy. Exogenous applications of MLE30, BAP, KCl and H2O to AARI-11 plants helped in ameliorating the water stress effects during the water deficit conditions and motivated the enzymatic antioxidants defense system to maintain its ionic homeostasis status. The maximum release of SOD, POD, CAT enzymatic contents due to the application of MLE30 and BAP probably has the ability to mitigate the effect of water stress during the applied irrigation water-regimes at T+B and T+H stages of AARI-11 plants (Farooq et al., 2009). On the other hand, non-enzymatic antioxidants (AsA) played crucial role in scavenging ROS and triggering the antioxidant defensive system against water deficit stress in wheat plants. The foliar application with MLE30 and BAP enhanced the production of AsA which increased the plant tolerance and improved photosynthetic activity in AARI-11 cultivar under irrigation water-regimes at T+B and T+H stages (Hanaa et al., 2008). The foliar application of MLE30 played an important role in protective measures against oxidative damage stress in wheat cultivar AARI-11 and enhanced the activities of TPC under irrigation water-regimes of T+B and T+H during the both years. The ability of MLE30 foliar agent to initiate the positive release of antioxidants is due to the presence of zeatin in it, which reduced the water stress and also promoted leaf chlorophyll contents “a” and “b” that has a vital role in photosynthesis process (Foidle et al., 2001).

Crop yield is based on chlorophyll contents and photosynthesis rate during the normal environmental conditions. The present study described that increased chlorophyll contents “a” and “b” in AARI-11 plants were due to their larger leaf area, and exogenous application of growth enhancer facilitated the photosynthetic rate under water deficit conditions especially at irrigation water-regimes of T+B after control and CRI+T+B stages, respectively (Ali et al., 2011). Similarly, Yasmeen et al. (2013) reported significance of MLE30 as moringa leaves contain a heavy amount of mineral contents including K+ which is an excellent plant growth enhancer/regulator. Leaf K+ content in AARI-11 plants with the application of MLE30 and BAP attributed direct increase in the K+ content which ultimately enhanced the uptake of K+ during the stomatal conductance (Cakmak, 2005).

Wheat yield depends on numbers of fertile/productive tillers and grain weight at harvest. The maximum production of fertile tiller in AARI-11 was due to its greater tolerance against water deficit stress and in addition to foliar application, of MLE30 and BAP at tillering and heading stages which resulted in increased number of grains per spike and 1000-grain weight under control, followed by T+H and T+B irrigation water-regimes (Baque et al., 2006). Biological yield was significantly prominent in AARI-11 plants. It might be possible that the foliar application of MLE30 and BAP at heading stage mitigated the water scarcity impact in wheat which increased grain yield not only in control, but also in T+B and T+H irrigation water-regimes (Yasmeen et al., 2012). Tillering and heading are the most important stages for the foliar application of growth regulators. At the tillering stage, MLE30 promoted the booting and similarly at the heading stages enhanced the grain filling and milking which led to increased biological yield and grain yield (Farooq et al., 2014). The foliar application also increased the harvest index (HI) during the both years, but MLE30 growth stimulator gave the maximum HI possibly due to its role in dry matter accumulation under various irrigation water-regimes i.e. control, CRI+T+B, T+B, and T+H, respectively, (Madani et al., 2010). Economic analysis illustrated that foliar application of MLE30 was a cost effective strategy for an increased benefit cost ratio of wheat.

Conclusion

The foliar application of naturally occurring MLE30 growth enhancer at the tillering and heading stages of wheat cv. AARI-11 ameliorated the water deficit stress by enhancing the antioxidants contents to protect it against oxidative damage which modulated yield related components under irrigation water-regimes at T+B and T+H over control (CRI+T+B+H).

Future research needs

Mechanism of photosynthetic product distribution and assimilation needs to be investigated after MLE application.

Author contributions

NH Supervisor Helped in supervised the research project and guide in conducting the research in the Field. HN student, performed all the activities during the research including research planning, lab analysis, write up. AY Co-supervisor, helped in lab analysis and data analysis. MA Help in review the article and guide in improving the article.

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Acknowledgments

The authors are grateful to “Bahauddin Zakariya University Multan, Pakistan” for financial support for this study through research project No. MRO/D-108 titled “Improvement in growth, yield and antioxidant status of wheat with exogenous application of growth enhancer under drought stress condition.”

Glossary

Abbreviations

AsA

ascorbic acid

BAP

benzyl-amino purine

B

booting

BCR

benefit cost ratio

CRI

crown root initiation

Chl.

chlorophyll

CAT

catalase

H

heading

MLE

moringa leaf extract

POD

peroxidase

ROS

reactive oxygen species

SOD

superoxide dismutase

T

tillering

TPC

total phenolic contents

TSP

total soluble proteins.

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