PHYTOMORPHOLOGY OF WHEAT AND ITS GRAIN QUALITY RESPONSE TO DIVERSEAPPROACHES OF IRON APPLICATION

Agriculture soils of Pakistan are already deficient of macronutrients, and now inadequacy for micronutrients has also been reported causing adverse effects on crop productivity. The study was carried out to investigate the effect of soil and foliar applied iron (Fe) on wheat. The treatments included: T 1 =Control (without Fe), T 2 =Soil applied Fe 3 kg ha -1 , T 3 =Soil applied Fe 6 kg ha -1 , T 4 =Foliar applied Fe 0.2%, T 5 =Foliar applied Fe 0.4%, T6=Soil applied Fe 1.5 kg ha -1 +foliar applied Fe 0.1%, T7=Soil applied Fe 1.5 kg ha -1 +foliar applied Fe 0.2%, T8=Soil applied Fe 3 kg ha -1 +foliar applied Fe 0.1% and T9=Soil applied Fe 3 kg ha -1 +foliar applied Fe 0.2%. All the treatments as alone or in combination, affected growth, yield and quality of wheat significantly (P<0.05). The results showed that T 9 and T 3 were most promising for almost all studied traits. Under T 9 and T 3 , variety “TD-1” produced plants of 59.44 and 59.09 cm, while “Sindhu” showed 92.9 and 75.98 cm height, respectively. Higher grain yield (4799.7 and 4760.5 kg ha -1 ), grain protein (17.22 and 17.13%) were also recorded in T 9 and T 3 , respectively; while T 1 remained the least. In varieties, “TD-1” produced higher grain yield (4788.9 kg) than “Sindhu” (4341.8 kg ha -1 ). Inversely, grain protein was higher in variety “Sindhu” (17.10%) than “ TD-1” (16.72%). It was concluded that soil applied Fe 3 kg ha -1 +foliar Fe 0.2% concentration or in absence of foliar application, soil applied Fe at 6 kg ha -1 remained most appropriate dose for wheat growers in addition to recommended NPK.


INTRODUCTION
Wheat (Triticum aestivum L.) is the major source of plant based human nutrition and is a essential part of daily dietary needs (Bouis, 2003;Dewal and Pareek, 2004;Ghasemi-Fasaei and Ronaghi, 2008;Nawab et al., 2006).This crop ensures food security of the country and cultivated over 22 million acres; accounts for 7.8 percent of the value added in agriculture and 1.8 percent of GDP (GoP, 2023).Self-sufficiency in wheat has always been a national objective and thus challenges for the agriculture experts and policy makers.As strategic crop, any shortfall in wheat production can create a crucial situation leading to political uncertainty, significant amount of foreign reserves is spent on imports, rise in prices of wheat flour and pocket shortages in vulnerable areas.During 2021-22, area sown decreased to 8,976 thousand ha -1 (2.1%) against last year's area (9,168 thousand ha 1 ).The production of wheat declined to 26.394 million tons (3.9 %) over 27.464 million tons of last year .The declined production was associated with decline in area sown, acute shortage of irrigation water and drought conditions at sowing, less fertilizers uptake and heat wave at grain formation stage (GoP, 2023).Wheat is the source of food for more than 60 percent of population in Pakistan and thus, the health of millions of people is directly influenced by the grain quality and nutrients (Iftikhar et al., 2019;Khan et al., 2010).More than 25% of world population is affected by micronutrient deficiencies in food products, a problem which is known as hidden hunger (Muthayya et al., 2013).The application of micronutrients mixed with macronutrients increases plant growth, yield and grain quality (Murphy et al., 2008;Sanchez & Swaminathan, 2005;Saquee et al., 2023).Among micronutrients, the effect of iron (Fe) in wheat based food is crucial for human health (Abbas et al., 2009;Afshar et al., 2020;Chen et al., 2018;Inayat et al., 2014;Nadim et al., 2013;Ziaeian & Malakouti, 2006).Iron is among essentially required 17 distinct nutrients for plants to achieve their full potential in terms of growth and development (Iqbal et al., 2011;Wasaya et al., 2021).Fe is essential for chlorophyll production in wheat, which keep the plant leaves looking healthy and green;in result, it is existed in most of enzymes to helps the plant produce energy by checking soil nitrate and soil sulfate (Rawashdeh et al., 2023;Saquee et al., 2023).Fe concentrations in plant tissues can range anywhere from 200 to 400 ppm.However, for healthy plants, this rate has to be over 100 ppm in order to avoid showing any signs of chlorosis, which most frequently manifests itself in the younger leaves (Shahrokhi et al., 2012;Soetan et al., 2010).Iron chlorosis, which is caused by Bicarbonate (HCO3) prevents body to absorb Fe (Ali et al., 2013;Ali et al., 2020;Aziz et al., 2019).Fe deficiencies are not always visible in plants grown in most calcareous soils, frequently suffer from Fe shortages (Assunco et al., 2022).In combination with macronutrients, the application methods that are employed to supply crops with micronutrients have an effect on the growth and output of the crops.Chaudry et al. (2007) found that the most effective strategy to increase wheat grain yield was to apply Fe and other micronutrients to the leaves of plant in foliar form but irrespective of application methods, the combined use of micronutrients results in improvement of the plant quality and output (Malakouti, 2008).According to Arif et al. (2006) foliar applied micronutrients at tillering, jointing, and booting stages of wheat caused an increase in yield and grain quality.They also concluded that the use of foliar fertilizer is potentially productive method for increasing the concentration of micronutrients in wheat grain and the bioavailability of applied elements (Ali et al., 2020).Foliar Fe application had a substantial impact on the grain Fe content of wheat; however, there was no significant interaction between genotype and Fe treatment (P>0.05).After foliar Fe treatment, there was no noticeable difference between cultivars and landraces in terms of the amount of Fe present or the yield (Hao et al., 2021).Among various fortification techniques, soil applied Fe is considered as most cost-effective, rapid, and sustainable strategy to improve the contents of micronutrients in wheat grains to alleviate the widespread Fe deficiencies in humans.FeSO4 is widely applied inorganic fertilizer as Fe source, due to its high solubility and low cost.It is evident that Fe fertilizer effectively improves wheat grain concentration and economic yield in Fe-deficient regions (Rawashdeh et al., 2023).The FeSO4 application through soil enhances grain quality of wheat.According to Niyigaba et al. (2019), soil applied Fe was more effective method for increasing the grain Fe as compared to its foliar application.Wheat output and quality are both increased when the micronutrient is used through soil (Moreno-Lora & Delgado, 2020).Similarly, Hao et al. (2021) concluded that grain Fe was 41.0 mg kg -1 when wheat fields were supplied with FeSO4 at 20 kg ha -1 .The Fe content of grains, as well as the bioavailability of Fe, were unaffected by foliar Fe treatment, but influenced significantly (P<0.05) when Fe was applied through soil regardless of varieties (Hao et al., 2021).In regions of less precipitation, micronutrients can be effectively used both through soil and by foliar method.Although, the Fe required by wheat is very small but in order to completion of crop life cycle, Fe would be essentially required.Adequate Fe concentration in plant tissue may be in the range of 50-250 ppm, while in grain it may be in the range of 25-35 ppm (Cakmak et al., 2010).In conditions, when plenty of irrigation water is available, Fe application through soil serves the purpose effectively (Naz et al., 2015); while in drought conditions of water shortage circumstances, in combined to soil application, foliar application on leaves works more effectively to improve crop productivity and grain quality (Fernandez et al., 2009).It was hypothesized that proper fertilization of Fe may play crucial role in improving growth, yield and nutritional quality of wheat and can help in resolving the malnutrition issue of populations.Therefore, this research was conducted to investigate the impact of Fe application through soil at various rates and through foliar application at different concentrations on the plant morphology, yield and grain quality of two wheat varieties.

MATERIALS AND METHODS
In order to examine the effect of soil and foliar applied Fe (separately and in integration) on growth, yield and grain quality of two wheat varieties (TD-1 and Sindhu) the trial was conducted during Rabi, 2020-21 and 2021-22 at the Students' Experimental Farm, Sindh Agriclture University Tandojam (25 o 26' o N latitude and 68 o 32' o E longitude).The land was prepared by two dry plowings followed by heavy soaking dose.When soil came in workable condition, precision leveling of land was carried out, followed by two cross-wise plowings with cultivator and planking with patio to achieve fine seedbed, bunds and feeding water channels were prepared.Sowing of wheat was done by single coulter hand drill in each experimental unit.The experiments were laid out in Randomized Complete Block Design (Factorial) with 3-replicates in net plot size of 6 m x 3 m = 18 m 2 , keeping 75 cm row spacing.The research comprised of nine treatments i.e T1= Control (without Fe), T2= Soil applied Fe 3 kg ha -1 , T3= Soil applied Fe 6 kg ha -1 , T4= Foliar applied Fe 0.2%, T5= Foliar applied Fe 0.4%, T6 = Soil applied Fe 1.5 kg ha -1 + foliar applied Fe 0.1%, T7 = Soil applied Fe 1.5 kg ha - 1 + foliar applied Fe 0.2%, T8 = Soil applied Fe 3 kg ha -1 + foliar applied Fe 0.1% and T9 = Soil applied Fe 3 kg ha-1 + foliar applied Fe 0.2%.Ferrous Sulphate Crystal (FeSO4), density 2.84 g/cm 3 , melting point 70 o C, molar mass 151.908 g/mol, was purchased from Al-Beruni Scientific Store, Hydeerabad.When applied through soil, the per hectare quantity as per the treatment plan was calculated on the basis of plot size, and applied as basal dose.In case of foliar application, FeSO4 was mixed in water at certain percentage (as per treatment plan) in a 100 litre water tanks and sprayed with knapsack hand sprayer on crop leaves at tillering, flowering and grain filling stages.Six irrigations were applied throughout the growing season of wheat.The first irrigation was applied at 30 to 35 days after sowing (DAS); whereas, subsequent irrigations were applied as per the crop requirement.The NPK fertilizers were applied as recommended (120-90-60 kg ha -1 ) locally for Sindh province.The N was applied in the form of urea (46% N) and DAP (18% N); P in the form of Di-Ammonium Phosphate, 46% P2O5(DAP) and K in the form of Sulphate of Potash, 50% K2O (SOP).All P, K andFe in combined tohalf of N were applied as basal application; while remaining N was applied in two splits.The weeds in the experimental wheat cropwere removed manually.The harvesting of experimental crop in all the treatments was manually done in the last week of March in both the years.
For recording the data, the plant was measured for height (cm) from ground to apex before harvest using a measuring tape; while for counting tillers number, one meter sequare area was selected in each treatment and the total number of tillers were counted manually.For spike length measurement, the measuring tape was used; while for recording the number of grains spike -1 , entire grain of the labelled plants was gathered, manually counted and averaged in grams.The seed index value was worked out on the basis of 1000 grains weight from the grain lot of each treatment and averaged in grams.The biological yield is the total crop biomass, and it was collected from all treatments separately, the bundles were tied with ropes and shifted to the threshing yard.Before threshing to separate the grain and straw/husk, the total biological yield was weighed using a field balance and averaged in kilograms per plot.Later, the per plot yield was calculated to achieve biological yield ha -1 using the following formula: Biological yield (kg ha -1 ) = Biological yield plot -1 (kg) x 10000 Net plot size (m 2 ) Similarly, for achieving the grain yield, each of the tied bundles were threshed separately for each treatment and grain yield per plot (kg) was converted into grain yield ha -1 by using the following formula: Grain yield (kg ha -1 ) = Grain yield plot -1 (kg) x 10000 Net plot size (m 2 ) The harvest index was calculated on the basis of biological yield and grain yield; considering grain yield as percentage of the biological yield per hectare using the following formula: Harvest index (%) = Grain yield (kg ha -1 ) x 100 Biological yield (kg ha -1 ) The leaf area (cm 2 ), leaf area index (%) and crop growth rate (CGR) of wheat varieties were determined as per the respective formula given hereunder: Leaf Area (cm 2 ) = Leaf length × Leaf breadth × Factor (0.75) Leaf area index (%) = Leaf area (cm 2 ) x 100 Ground area (cm 2 ) CGR g m -2 day -1 = W2 -W1 x 1 T2 -T1 GA Where; W1 = Weight at T1 of the period W2 = Weight at T2 of the Period T1 = Time in date at the start of the period T2 = Time in the date at the end of the period GA= Ground area The total dry matter was observed by oven drying samples at 70 o C for 48 hours (2 days) and then weighed and averaged.In case of grain quality analysis, Similarly, the grain Fe was determined by DTPA Method The diethylenetriaminepentaacetic Acid (DTPA) test of Lindsay and Norvell (1978).DTPA method has a capacity to complex each of the micronutrient cations as 10 times of its atomic weight.The capacity ranges from 550 to 650 mg kg -1 depending upon the micronutrient cations as suggested by ICARDA (2013).However, grain protein content was determined on the basis of grain N content by multiplying a factor i.e 6.25.Grain protein content in seed = N % in seed multiplied by factor 6.25 (AOAC, 1984).
The collected data were subject to statistical analysis using Statistix 8.1 computer software.The two-way ANOVA was developed to examine significance of the effects on studied parameters due to treatments and their interactions.The LSD test was applied to compare treatments' mean considering the significance of the treatments' effect (Steel et al., 1997).

DISCUSSION
Frequent use of NPK by the farmers to achieve higher crop yields with least or no awareness about the significance of micronutrients, the agriculture soils have become severely inadequate of organic matter and essential needed macro-and micronutrients (Bloemberg & Lugtenberg, 2001).The success of wheat production is reliant on soil available N, P and K. Thus, application of micronutrientsat increased concentrations can potentially increase wheat yields and improve grain quality as well.The wheat crop needs distinct nutritional requirements at various stages of its lifecycle, and these requirements may change over time.There are three major critical phases throughout the growth cycle of wheat crop in which nutrients play an especially vital role.At budding stage, leaf feeding stimulates the development of the main shoot as well as the emergence of side shoot buds in the axils of the germinating leaves and the expansion of the germ system; while at tillering stage, the emergence of tillers activates morphophysiological processes, guaranteeing the development of a secondary root system.At the flag leaf stage, which marks the beginning of the emergence of the ear.Thus, using certain methods at the most suitable application stage can maximise the availability of micronutrients (Cakmak et al., 2010;Goel et al., 2021;Iftikhar and Ali, 2017;Rawashdeh et al., 2023).
Among micronutrients, Fe (Fe) has crucial role in crop growth dynamics, yield and produce quality.In this study the effect of Fe (soil, foliar and integrated use) on the growth, yield and grain quality of wheat varieties.The study showed that soil applied Fe (Fe) 3 kg ha -1 +foliar Fe 0.2% concentration and soil applied Fe 6 kg ha -1 only showed most promising results for almost all the agronomic parameters including grain yield and grain quality traits recording greater values for representative traits such as plant height (76.16 and 75.98 cm), grain yield (4799.7 and 4760.5 kg ha -1 ), grain protein (17.22 and 17.13%), respectively.
The findings of the present research are in agreement with many past workers.According to a recent study, the Fe is essential to the grain and chlorophyll production in wheat, which is necessary for the plant to keep leaves healthy and green.Moreover, due to majority of enzymes after Fe application in plants, the plant produce energy by reducing the amounts of nitrate and sulfate in the soil (Impa et al., 2019;Jalal et al., 2020;Kihara et al., 2020;Rawashdeh et al., 2023).Similarly, the interveinal chlorosis also known as Fe deficiency in plants caused yellow-green bands on young leaves caused by insufficient amount of chlorophyll production in result Fe deficiency in the plant occurs (Saquee et al., 2023).In case the Fe is not added to the soil under inadequate conditions, the leaves become yellow, and the chlorosis spreads to older leaves (Shahrokhi et al., 2012).The Fe cause the production of chlorophyll due to cytochromes and electron transport systems both need Fe as constituent (Soetan et al., 2010).Fe chlorosiscaused by HCO3 that prevents plants from Fe absorbtion (Makawita et al., 2021).According to Ziaeian & Malakouti (2006), the increased concentrations of Fe boost productivity and quality of wheat grain.He also indicated that in combined to NPK, the application of Fe or mixture of micronutrients had positive influence on grain production and quality in wheat.Abbas et al. (2009) showed thatFe applied 12 kg ha -1 not only improved grain yield, but the grain quality (grain protein) was also improved.However, higher Fe rates than the above levels had no positive and significant effect on grain yield and quality.Hafeez et al. (2021) acquired highest starch content in grain when Fe was added in combined to usual NPK fertilizers in wheat.Similarly, Niyigaba et al. (2019) revealed that utilization of a 100 percent Fe supplement was the most effective method for increasing the amount of Fe found in grain (13 kg ha - 1 ).It is essential to apply Fe to wheat crop at the foliar stage in order to increase the grain Fe, grain protein contents and improve the overall quality of the crop produce.When Fe was used in conjunction other micronutrients, it was shown to be an effective strategy.In combined , the grain crude fat content was unchanged by any of the Fe-containing treatments, and the grain crude fiber content was enhanced by as much as three times the average when using 60% Zn + 40% Fe 5.5 (5.5 kg ha -1 of 60% Zn + 40% Fe) (Li et al., 2016;Maryami et al., 2020;Niyigaba et al., 2019).
The wheat yield and quality both increased when the micronutrient Fe was used as fertilizer.Moreover, the incidence of anemia caused by a lack of Fe in food also lowers (Ali et al., 2022;Pallavi and Sudha, 2017;Ramzan et al., 2020).
Since, Fe has pivotal role in chlorophyll synthesis, because it is a component of cytochromes and electron transport.Its inadequacy adversely affects the activity of various enzymes including catalase and peroxidase having porphyrin as a prosthetic group and iron chlorosis impairs the Fe uptake mechanism.To alleviate nutrient imbalance, plants use different mechanisms to decrease water loss when increasing water uptake, that may reduce leaf area and osmotic adjustment when organic compounds and minerals elements are applied (Hussain et al., 2021;Soetan et al., 2010).Makawita et al. (2021), andRehman et al. (2020) clearly showed the evidence about the effectiveness of Fe fertilizer to improve wheat yield and grain nutrient concentration.The application of FeSO4 enhanced quality of wheat grains and increased nutrient contents in wheat grain.

CONCLUSIONS
The results concluded that soil applied Fe when applied in wheat (3 kg ha -1 ) in integration to foliar applied Fe (0.2%) or soil applied Fe at higher level (6 kg ha -1 ) resulted in most promising results for growth, yield and grain quality traits; with greater values for grain yield (4799.7 and 4760.5 kg ha -1 ) and grain protein (17.22 and 17.13%), respectively.
Response of wheat to foliar application of nutrients.International Journal of Agriculture and Biology 4, 30-34. (2006).

Fig 2 :
Fig 2: Effect of soil and foliar applied Fe (Treatments) on biological yield (kg ha -1 ) of wheat varieties

Fig 3 :
Fig 3: Effect of soil and foliar applied Fe on grain yield (kg ha -1 ) of wheat varieties Table 3. Harvest index, spike length and grains spike -1 of wheat as affected by levels and methods of Fe

Fig 6 :
Fig 6: Effect of soil and foliar applied Fe (Treatments) on grain protein (%) of wheat varieties