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Article

Reduction of Potassium Supply Alters the Production and Quality Traits of Ipomoea batatas cv. BAU Sweetpotato-5 Tubers

by
Shaila Sharmin
1,
Md. Nazmul Hasan Arfin
1,
Abu Musa Md Main Uddin Tareque
2,
Abdullah Al Kafi
1,
Md. Shohidullah Miah
1,
Md. Zakir Hossen
3,
Md. Abdus Shabur Talukder
1 and
Arif Hasan Khan Robin
2,*
1
College of Agricultural Sciences, International University of Business Agriculture and Technology, Dhaka 1230, Bangladesh
2
Department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
3
Department of Agricultural Chemistry, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
*
Author to whom correspondence should be addressed.
Stresses 2024, 4(4), 883-895; https://doi.org/10.3390/stresses4040059
Submission received: 18 November 2024 / Revised: 6 December 2024 / Accepted: 9 December 2024 / Published: 11 December 2024
(This article belongs to the Section Plant and Photoautotrophic Stresses)
Browse Figures
Versions Notes

Abstract

:
In Bangladesh, sweetpotato is the fourth most important source of carbohydrates behind rice, wheat, and potatoes. Potassium is vital for sweetpotato growth, boosting tuber size, sweetness, disease resistance, and yield quality, with deficiencies leading to poor tuber formation and increased stress susceptibility. The present study evaluated the effect of varying dosages of potassium fertilizer (Muriate of Potash, MoP) on the growth, yield, and biochemical qualities of sweetpotato. As a genetic material, BAU sweetpotato-5 was chosen as it is recognized for its high yield, short duration, and nutritional advantages. There were three treatments—full dosage of MoP (321.6 kg ha−1, T0), half dosage of MoP (160.8 kg ha−1, T1) and no MoP (T2). Four replications of a randomized complete block design (RCBD) were used in the experiment. According to analysis of variance, the morphological and biochemical parameters, such as the fresh weight plant−1, number of tuber plant−1, chlorophyll content, total phenolic content, vitamin C, carotenoid, anthocyanin, Zn, and Fe content varied significantly among treatments. The application of the full recommended dosage of MoP resulted in the highest values for several traits, including the fresh weight plant−1, number of tuber plant−1, chlorophyll content, carotenoid, anthocyanin, and Fe content. Conversely, total phenolic content and vitamin C were highest without MoP application. Principal component analysis (PCA) differentiated treatment T0 from T1 and T2 due to higher positive coefficients of the number of leaves at 115 days after transplantation, vine length at 115 days after transplantation, number of branches, stem diameter, fresh weight plant−1, tuber length, tuber diameter, tuber weight, number of tuber plant−1, SPAD, carotenoid, anthocyanin, Fe, and negative coefficients of total phenolic content, vitamin C, and Zn. The findings suggest that potassium is integral to maximizing both yield and key nutritional components in sweetpotato cultivation.

1. Introduction

Sweetpotato (Ipomoea batatas), a member of the Convolvulaceae family, is a significant root crop mostly cultivated in tropical and subtropical regions of Asia, the tropical Americas, the Pacific Islands, and Papua New Guinea [1]. To date, sweetpotato is the seventh most important global agricultural crop, producing 86.41 million metric tons globally [2]. It has a wide range of adaptability, making production possible in marginal agricultural settings. This adaptability has made the sweetpotato incredibly important for food security in developing countries. Globally, more than 95 percent of sweetpotatoes are cultivated in developing countries, where both the leaves and tubers are consumed by people and used as feed for livestock [3].
In Bangladesh, sweetpotato is the fourth most important source of carbohydrates after rice, wheat, and potato, with a production of 304 kilo tons in 2022, which was 8.55% more than in the previous year [4,5]. This is largely due to the introduction and adoption of modern varieties developed by the Bangladesh Agricultural Research Institute (BARI) and agricultural universities, along with improved cultivation techniques and increased awareness among sweetpotato growers. The crop also significantly boosts farmers’ incomes in Bangladesh [5].
As a sustainable crop, sweetpotato is used to make various high-quality, nutritionally enhanced food products that support human health. It is rich in vitamins and minerals, including ß-carotene, anthocyanins, and beneficial fibers [6]. The antioxidantive, vitamin, and mineral contents of sweetpotato make it a “superfood”. Calorie-wise, sweetpotato is an ideal food [7].
BAU sweetpotato-5, a high-yielding variety, recently developed by Bangladesh Agricultural University, produces 30–35 tons per hectare with a short growth period. On average, each tuber’s weight is 200–300 g [8].
Potassium (K) is an essential macronutrient that plays a significant role in the growth and development of sweetpotatoes. In Bangladesh, Muriate of Potash (MoP) is mainly applied to the field as a source of K. Bangladesh requires around 0.75 million metric tons of MoP fertilizer each year [9].
Sweetpotato, sugarcane and cassava have high potassium requirements because their leaves, vines, stems, and tubers typically extract a significant amount of K from the soil. Potassium is crucial for photosynthesis and energy transfer. It regulates the opening and closing of the stomata, which facilitates gas exchange and optimizes the photosynthetic process. Enhanced photosynthesis leads to increased carbohydrate production, which is vital for tuber development [10,11]. Moreover, it helps to regulate water use efficiency and turgor pressure within plant cells. It aids in osmoregulation, which is particularly important for sweetpotatoes that can experience water stress. Adequate potassium enhances drought tolerance and overall plant vigor [12]. Furthermore, potassium promotes root development and is essential for the proper formation and quality of sweetpotato tubers. Strong root systems enhance nutrient and water uptake, which is essential for healthy growth and higher yields [13]. Besides, potassium enhances the uptake of other essential nutrients, such as nitrogen and phosphorus. This synergistic effect leads to improved plant health, growth, and ultimately, yield [14]. In addition, adequate potassium levels strengthen plant tissues, enhancing resistance to diseases and pests. This is particularly important for sweetpotatoes, which can be susceptible to various pathogens [15].
However, potassium deficiency in sweetpotatoes can severely impact plant health, yield, and quality. The effects of potassium deficiency are noticeable through various symptoms. First of all, potassium-deficient sweetpotatoes typically show chlorosis, visually observed as yellowing along the leaf margins of older leaves, which can progress to necrosis [16]. Secondly, deficiency in potassium can lead to smaller tubers, lower starch content, and reduced dry matter, which negatively impacts both the quality and yield of sweetpotato crops. This also reduces the marketability and nutritional value of the produce [17]. Thirdly, potassium-deficient plants are more vulnerable to pest infestations and diseases like Alternaria leaf spot and root rot. Studies have shown that adequate potassium can reduce the incidence of disease and improve plant resilience [13]. Finally, potassium deficiency can result in weaker, less developed roots, limiting the plant’s capacity to absorb water and other essential nutrients, further exacerbating growth issues [18].
Potassium is a macronutrient which is essential for the tuber development of sweetpotato; the impact of a reduced K supply may alter production and biochemical qualities of sweetpotato tubers. Hence, the incorporation of MoP fertilizer in sweetpotato plant production holds significant potential for improving yield quantity and quality. Consequently, this study assessed the comprehensive effects of MoP fertilizer on shoot morphology, tuber production and biochemical qualities of sweetpotato variety BAU sweetpotato-5.

2. Results

2.1. Analysis of Variance

According to the analysis of variance, there were significant variations among treatments for the morphological traits, namely the fresh weight plant−1 and the number of tuber plant−1 (Table 1). The treatment mean sum of squares was significant at 5% level (p ≤ 0.05) for the aforementioned traits. The highest fresh weight plant−1 was obtained when full dosage of MoP was applied (T0) (Table S1, Figure 1). This value decreased significantly by 41.7% and 48.5% in T1 and T2, respectively, with the decrease in MoP fertilizer. Similarly, T0 treatment received the highest number of tuber plant−1. T1 and T2 treatment decreased the number of tuber plant−1 by 18.5% and 29.63%, respectively, (Table S1, Figure 1).
Furthermore, there were notable variations among the treatments for the biochemical traits such as chlorophyll content (SPAD), TPC (mg 100 g−1 fresh tuber), vitamin C (mg 100 g−1 fresh tuber), carotenoid (mg 100 g−1 fresh tuber), anthocyanin (mg 100 g−1 fresh tuber), Zn (mg kg−1), and Fe (mg kg−1) content (Table 1). The analysis of variance in this study revealed that the treatment difference was significant at 5% (p ≤ 0.05), 1% (p ≤ 0.01), and 0.1% (p ≤ 0.001) for the biochemical traits.
Chlorophyll content (SPAD) varied among the treatments with T0 having the highest SPAD value (Table S2). With the reduction of K supply, the SPAD value was reduced by 8% in T1 and 22% in T2 (Figure S1). On the other hand, total phenolic content and vitamin C were the highest when no MoP application existed (T2) (Table S2, Figure 2). With the increase in potassium supply, these two values decreased significantly and reached the lowest in T0, both reduced by 31% (Figure 2). However, carotenoid and anthocyanin had different trends. Both carotenoid and anthocyanin had their highest value, with the highest potassium applied (T0). Carotenoid had its lowest value at T1 with a 45% reduction while T2 received the lowest for anthocyanin with a 35% reduction (Table S2, Figure 2). Zinc (Zn) content was highest in T1 and lowest in T0 with a 25% reduction, while Fe content was highest in T0, and by reducing it by 46.7%, the value reached the lowest in T1 (Table S2, Figure 3).

2.2. Trait Association

The correlation coefficients among different morphological and biochemical traits are displayed in Figure 4. The correlation analysis indicated that out of 110 associations, 8 associations were significant. Five associations were positively correlated, and three were negatively correlated (Figure 4). Anthocyanin had a positive significant correlation with tuber diameter and fresh weight plant−1. Furthermore, vine length at 115 DAP and carotenoid were positively correlated with each other and stem diameter (Figure 4). Vitamin C had a significant negative correlation with the number of tuber plant−1. In addition, the number of branches and number of leaves at 115 DAP were negatively correlated with Zn and Fe, respectively (Figure 4).
Principal component analysis (PCA) identified the most significant relationships among the morphological and biochemical traits in this study. The first three principal components (PC) explained 77.5% of the total data variation for the effect of treatments on morphological and biochemical traits. PC1, PC2, and PC3 explained 45.4%, 19.9% and 12.2% data variation, respectively (Table 2). The eigenvalues of the first three PCs were greater than one.
The first principal component (PC1) explained the highest variation (45.4%) of the data, with strong positive coefficients for the morphological and biochemical traits, namely number of leaves at 115 DAP, vine length at 115 DAP, number of branches, stem diameter, fresh weight plant−1, tuber length, tuber diameter, tuber weight, number of tuber plant−1, SPAD, carotenoid, anthocyanin, and Fe and negative coefficients of total phenolic content, vitamin C, and Zn. PC1 showed a highly significant difference among treatments (Table 2). The PC1 clearly separated treatment T0 from T1 and T2 in terms of morphological and biochemical traits, as evidenced by their differential location in the biplot (Figure 5).
PC2 explained 19.9% of the total variation, which is mostly dominated by the negative coefficients of the number of leaves at 115 DAP, vine length at 115 DAP, number of branches, fresh weight plant−1, tuber length, tuber diameter, tuber weight, SPAD, and vitamin C and Zn content. Both PC2 and PC3 separated treatment T1 from T2 for positive and negative PC scores, respectively (Figure 5 and Figure S2).

3. Discussion

This study was conducted to analyze the effect of reduced supply of potassium fertilizer (MoP) dosages on morphological and biochemical properties of sweetpotato.
At harvest, fresh weight plant−1 and tuber number plant−1 obtained the highest value when the full dosage of K was applied. Increased tuber weight and tuber number plant−1 that ultimately increase the tuber yield are highly dependent on potassium application. This may be because potassium plays a pivotal role in photosynthesis, promotes a high energy state, and aids in the crop’s timely and proper nutrient translocation and root water absorption. As a result, there are more photosynthates available, which allows the plant to grow more tubers [19].
Potassium is essential for the synthesis of chlorophyll, the green pigment, critical for photosynthesis. It is vital for the opening and closing of the stomata, which allows efficient CO2 uptake for photosynthesis. Adequate potassium also boosts the production of carbohydrates and energy needed for chlorophyll synthesis [20]. Moreover, potassium activates enzymes essential for photosynthesis, particularly those that produce ATP and NADPH molecules that fuel photosynthetic reactions and aid in chlorophyll synthesis. The optimal functioning of these enzymes is critical for chlorophyll content and overall photosynthetic efficiency [21]. Furthermore, research shows that potassium reduces chlorophyll degradation by stabilizing cellular membranes and mitigating oxidative stress. In potassium-deficient plants, chlorophyll breaks down more readily, causing chlorosis and reducing photosynthetic efficiency [15]. In the current study, leaf chlorophyll content (SPAD) was highest when there was the full recommended dose of K fertilizer, indicating the positive relationship between higher chlorophyll content and an increased amount of potassium applied [22].
This study showed a different trend for total phenolic content and vitamin C [23]. It was observed that total phenolic content and vitamin C were the highest when no MoP was applied. Contrarily, Redovnikovic et al. [24], concluded that adequate potassium levels can enhance the activity of enzymes responsible for phenolic synthesis, leading to increased phenolic content in tubers. Furthermore, potassium promotes photosynthesis, which is essential for the synthesis of vitamin C in plants. Improved photosynthetic activity can lead to higher vitamin C levels in tubers [20] indicating that reduced potassium may reduce photosynthetic activity by decreasing overall shoot growth and chlorophyll content (Figure S1).
Carotenoid and anthocyanin contribute significantly to human health through their antioxidant, anti-inflammatory, and immune-boosting properties. Regular consumption of carotenoid and anthocyanin-rich foods can help reduce the risk of chronic diseases and support overall human well-being [25,26]. Potassium significantly impacts the availability and synthesis of carotenoids and anthocyanins in tubers by activating key enzymes, enhancing photosynthesis, and improving plant stress responses. Ensuring adequate potassium levels is crucial for optimizing the nutritional quality and visual appeal of tubers [27]. In this experiment, carotenoid and anthocyanin availability were increased with the increase of K supply. Nevertheless, Ooi et al. [28] found a contradictory result where the amount of these two pigments decreased with increased potassium. In plants, potassium influences enzyme activity and other pathways that might reduce the production of these pigments.
Zinc and Fe are essential trace elements that play critical roles in human health. Potassium significantly influences the availability and uptake of Zn and Fe in tubers by enhancing root development, improving soil conditions, and facilitating nutrient transport and metabolism. Maintaining adequate potassium levels is crucial for optimizing the nutritional quality of tubers [29]. In this experiment, Zn content was the highest while the half dosage of K was applied, and Fe content reached the highest value with the full recommended dosage.
Improving tuber yield involves studying the link between morphological traits and biochemical markers. By assessing these correlations, researchers can identify key yield-influencing traits, aiding in targeted breeding for higher-yielding crop varieties. In this study, anthocyanin was positively correlated with tuber diameter and fresh weight plant−1. In some potato varieties, higher anthocyanin content often accompanies greater fresh weight, as these anthocyanins are concentrated in the skin or flesh of larger, healthier tubers. Larger tubers tend to accumulate more anthocyanins, particularly in pigmented varieties, due to increased surface area or flesh volume for pigment synthesis [30]. Furthermore, carotenoid was positively correlated with stem diameter. In sweetpotatoes, thicker stem diameters often indicate robust growth, which supports nutrient and water transportation essential for carotenoid biosynthesis. Carotenoids are synthesized as part of the photosynthetic apparatus and are known to increase with plant vigor. A study by Brown [30], highlights that higher carotenoid concentrations are generally found in well-nourished, structurally healthy potato plants, which also tend to have thicker stems.
However, vitamin C had a significant negative correlation with the number of tuber plant−1. This is contradictory with other findings. According to Rosero et al. [31], environmental stressors such as drought or nutrient deficiencies can impact both tuber development and vitamin C synthesis. Under stress conditions, plants may produce fewer tubers and lower vitamin C levels. Conversely, well-managed environments that promote healthy growth often lead to higher tuber numbers and enhanced vitamin C content.
In addition, the number of branches were negatively correlated with Zn. Studies have indicated that excessive Zn can adversely affect plant morphology, leading to reduced branching. High levels of Zn can lead to imbalances in other essential nutrients, inhibiting branch development [32].
Optimal potassium fertilization enhances sweetpotato yield, tuber quality, and nutrient content by supporting photosynthesis, enzyme function, and nutrient uptake. Full potassium dosage increased the tuber number, fresh weight plant−1, chlorophyll content, carotenoid, and anthocyanin, while influencing key nutrients like vitamin C, phenolics, Zn, and Fe. These findings emphasize potassium’s vital role in enhancing sweetpotato productivity and nutritional quality, providing a foundation for optimized crop management practices.

4. Materials and Methods

4.1. Site and Soil Characteristics

This experiment was carried out in the agricultural research field of the International University of Business Agriculture and Technology (IUBAT) from October 2023 to March 2024. The research aimed to examine the effects of different MoP fertilizer dosages on the growth and yield of sweetpotatoes. The USDA soil taxonomy (USDA 1975) classifies the soil in this location as a gray terrace. It is in the Madhupur Tract (AEZ-28), an agroecological zone, and part of the Chhiata soil series. The biochemical properties of soil are given in Table 3.

4.2. Treatments

The sweetpotato variety known as BAU sweetpotato-5 was taken in this experiment. As treatments, varying dosages of MoP fertilizer were applied. In total, there were three treatments (Table 4). A randomized complete block design (RCBD) with four replications was used in this experiment (Figure 6). In this investigation, MoP fertilizer was used as a source of potassium and applied twice at 30 and 60 days after transplanting. The 1.0 m × 0.8 m plots received manures and fertilizers at the recommendation of the Bangladesh Agricultural Research Institute (BARI).

4.3. Planting of Vines

Vines of disease-free and healthy sweetpotato genotype (20–22 cm vine length with 5–6 nodes) were planted in rows on well-prepared soil with 0.6 m × 0.4 m spacings. The ridge approach was used to generate sweetpotato storage roots and leaves. To improve productivity, recommended dosages of fertilizers, fungicides, insecticides, and manures were applied. During plant growth, techniques such as vine lifting, weeding, irrigation three times, and earthing up the base of the crops were used. Fourteen days prior to the storage roots being harvested, the irrigation was stopped.

4.4. Data Collection

A variety of plant-related metrics, responsible for development, yield, and biochemical qualities were measured. Vine length (cm), number of leaves, number of branches, and stem diameter (cm) were the traits responsible for development. Data for these traits were measured from the largest vine at harvest. Traits contributing to yield such as fresh weight plant−1 (g), tuber length (cm), tuber diameter (cm), tuber weight (g), and number of tubers plant−1 were recorded at harvest. Furthermore, biochemical properties namely chlorophyll content (SPAD value), total phenolic content (TPC, mg 100 g−1 fresh tuber), vitamin C (mg 100 g−1 fresh tuber), carotenoid (mg 100 g−1 fresh tuber), anthocyanin (mg 100 g−1 fresh tuber), glucose, fructose, sucrose, Zn (mg kg−1), and Fe (mg kg−1) content in tubers were measured according to the following techniques.

4.5. Determination of Chlorophyll Content

A chlorophyll meter (SPAD-502, Minolta, Tokyo, Japan) was employed to determine the chlorophyll content of sweetpotato leaves.

4.6. Determination of Total Phenolic and Vitamin C

To determine total phenolics and vitamin C, a fully matured sweetpotato tuber was collected from each treatment. Total phenol estimation in sweetpotato was carried out with the Folin−Ciocalteau reagent [33]. The concentration of phenols in sweetpotato was calculated against the catechol standard curve and expressed as mg phenols/100 g material. On the other hand, to determine vitamin C content, about 10 g sweetpotato flesh was ground with 4% oxalic acid. The slurry was filtered, and the filtrate was collected into a volumetric flask. Then ascorbic acid (AA) content in sweetpotato was estimated based on the reduction of 2,6-dichlorophenol indophenol dye by visual titration as outlined by [33]. Results of vitamin C content were expressed as milligrams of AA per 100 g of fresh weight.

4.7. Determination of β-Carotene

A one-gram portion of a fresh tuber sample was crushed and meticulously blended with a 10 mL solution composed of acetone and hexane in a 4:6 ratio. Afterward, the mixture underwent centrifugation, and the optical density of the resulting supernatant was measured using a spectrophotometer, specifically UV-160A (Shimadzu Corp., Kyoto, Japan), at multiple wavelengths, including 663 nm, 645 nm, 505 nm, and 453 nm. Subsequent calculations were performed using the following formula [34].
β carotene (mg/100 g) = 0.216(OD 663) + 0.452(OD 453) − 1.22 (OD 645) − 0.304 (OD 505)
where OD indicates optical density.

4.8. Estimation of Anthocyanin

For anthocyanin quantification, 100 mg of fresh sweetpotato tuber samples were homogenized in 3 mL of acidic ethanol (95% ethanol with 1.5 N HCL). The mixture was incubated at 4 °C for 1 h with gentle agitation, followed by centrifugation at 8000 rpm at 4 °C for 10 min. Absorbance was then measured at 530 and 657 nm wavelengths using a UV-visible spectrophotometer [35], and the amount of anthocyanin was determined using the following formula:
QAnthocyanin = (A530 − 0.25 × A 657) × M−1
Here, QAnthocyanin = amount of anthocyanin
A530 and A657 = absorptions at the indicated wavelengths
M = weight of the plant materials (mg)

4.9. Determination of Zn and Fe

To determine the contents of Zn and Fe, collected sweetpotato samples were chopped into small pieces with a sharp stainless-steel knife and dried for roughly 72 hrs in an electric oven at a temperature of 50 °C. The samples were then pulverized in a grinding mill and utilized to make an extract by a wet oxidation technique using a di-acid mixture as outlined by [36]. Determination of Zn and Fe in aqueous extracts of sweetpotato was carried out using an atomic absorption spectrophotometer (AAS) (AA-7000, Shimadzu Corp., Japan). Hollow cathode lamps of Zn and Fe were employed as light sources at wavelengths of 213.9 and 248.3 nm, respectively. All instrumental parameters were adjusted according to the manufacturer’s instructions.

4.10. Statistical Analysis

Minitab 20 statistical software tools (Minitab Inc., State College, PA, USA) were used to conduct statistical analysis such as analysis of variance (ANOVA) and principal component analysis (PCA). Pearson correlation analysis was executed with R programming software version 4.4.1. A one-way analysis of variance (ANOVA) was performed for each morphological and biochemical feature using the general linear model (GLM) as a guide. As a post hoc study, Tukey’s pairwise comparison was used to identify any significant changes between treatments.

5. Conclusions

The current study was conducted to determine whether different potassium (K) fertilizer dosages affect tuber and yield-contributing characters. In addition, different biochemical properties were also analyzed to obtain a clear idea about tuber quality. This study revealed significant variations among treatments for several morphological and biochemical traits. All the morphological traits excluding the number of leaves at 115 DAP and tuber length had their highest value when a full dosage of MoP was applied. Among the biochemical traits, total phenolic, vitamin C, and Zn content reached their highest value in T2. In contrast, the rest of the biochemical properties had their highest value with a full dosage of MoP. Sweetpotato plants typically respond positively to K fertilization, as potassium is essential for their growth, tuber yield, and quality. However, excessive amounts may lower concentrations of beneficial compounds like carotenoids and anthocyanins.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/stresses4040059/s1. Table S1: Mean performance of BAU sweetpotato-5 for morphological traits under three treatments (T0 = 321.8 kg MoP ha−1, T1 = 160.8 kg MoP ha−1 and T2 = 0.0 kg MoP ha−1; Table S2: Mean performance of BAU sweetpotato-5 for biochemical traits under three treatments (T0 = 321.8 kg MoP ha−1, T1 = 160.8 kg MoP ha−1 and T2 = 0.0 kg MoP ha−1); Figure S1: Variation among three treatments (T0 = 321.8 kg MoP ha−1, T1 = 160.8 kg MoP ha−1 and T2 = 0.0 kg MoP ha−1 for leaf chlorophyll content (SPAD value); Figure S2: Scatterplot of PC1 and PC3 showing differences among treatments.

Author Contributions

Conceptualization, S.S. and A.H.K.R.; Data curation, S.S., M.N.H.A., A.A.K. and M.A.S.T.; Formal analysis, A.M.M.M.U.T. and M.Z.H.; Funding acquisition, M.Z.H. and A.H.K.R.; Investigation, S.S., M.N.H.A., A.A.K. and M.Z.H.; Methodology, S.S., M.N.H.A. and A.A.K.; Supervision, M.S.M.; Validation, M.S.M. and A.H.K.R.; Writing—original draft, S.S., A.M.M.M.U.T. and A.H.K.R.; Writing—review and editing, M.Z.H. and A.H.K.R. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

The data are available upon reasonable request from the authors.

Acknowledgments

The authors would like to express gratitude to the College of Agricultural Sciences of IUBAT, the Department of Genetics and Plant Breeding and Agricultural Chemistry of Bangladesh Agricultural University, the Plant Breeding division of the Bangladesh Rice Research Institute, Gazipur, and the Department of Horticulture of Sylhet Agricultural University for their cooperation to conduct and complete the analysis process for manuscript preparation.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. Variation among three treatments (T0 = 321.8 kg MoP ha−1, T1 = 160.8 kg MoP ha−1 and T2 = 0.0 kg MoP ha−1 for (a) fresh weight plant−1 (g) and (b) number of tuber plant−1.
Figure 1. Variation among three treatments (T0 = 321.8 kg MoP ha−1, T1 = 160.8 kg MoP ha−1 and T2 = 0.0 kg MoP ha−1 for (a) fresh weight plant−1 (g) and (b) number of tuber plant−1.
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Figure 2. Variation among three treatments (T0 = 321.8 kg MoP ha−1, T1 = 160.8 kg MoP ha−1 and T2 = 0.0 kg MoP ha−1 for (a) TPC (Total phenolic content, mg 100 g−1 fresh tuber), (b) vitamin C (mg 100 g−1 fresh tuber), (c) Carotenoid (mg 100 g−1 fresh tuber), (d) Anthocyanin (mg 100 g−1 fresh tuber).
Figure 2. Variation among three treatments (T0 = 321.8 kg MoP ha−1, T1 = 160.8 kg MoP ha−1 and T2 = 0.0 kg MoP ha−1 for (a) TPC (Total phenolic content, mg 100 g−1 fresh tuber), (b) vitamin C (mg 100 g−1 fresh tuber), (c) Carotenoid (mg 100 g−1 fresh tuber), (d) Anthocyanin (mg 100 g−1 fresh tuber).
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Figure 3. Variation among three treatments (T0 = 321.8 kg MoP ha−1, T1 = 160.8 kg MoP ha−1 and T2 = 0.0 kg MoP ha−1 for (a) Zn content (mg kg−1), (b) Fe content (mg kg−1).
Figure 3. Variation among three treatments (T0 = 321.8 kg MoP ha−1, T1 = 160.8 kg MoP ha−1 and T2 = 0.0 kg MoP ha−1 for (a) Zn content (mg kg−1), (b) Fe content (mg kg−1).
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Figure 4. Correlation coefficients among morphological and biochemical traits of BAU sweetpotato-5. Here, NL 115 DAP: number of leaves 115 days after transplanting, VL115 DAP: vine length 115 days after transplanting, NB: number of branches, SD: stem diameter (cm), FWP: fresh weight plant−1 (g), TL: tuber length (cm), TD: tuber diameter (cm), TW: tuber weight (g), NTP: number of tuber plant−1, TPC: total phenolic content (mg 100 g−1 fresh tuber), Vit-C: vitamin C (mg 100 g−1 fresh tuber).
Figure 4. Correlation coefficients among morphological and biochemical traits of BAU sweetpotato-5. Here, NL 115 DAP: number of leaves 115 days after transplanting, VL115 DAP: vine length 115 days after transplanting, NB: number of branches, SD: stem diameter (cm), FWP: fresh weight plant−1 (g), TL: tuber length (cm), TD: tuber diameter (cm), TW: tuber weight (g), NTP: number of tuber plant−1, TPC: total phenolic content (mg 100 g−1 fresh tuber), Vit-C: vitamin C (mg 100 g−1 fresh tuber).
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Figure 5. Biplot for morphological and biochemical traits of BAU sweetpotato-5. Here, NL 115 DAP: number of leaves 115 days after transplanting, VL115 DAP: vine length 115 days after transplanting, NB: number of branches, SD: stem diameter (cm), FWP: fresh weight plant−1 (g), TL: tuber length (cm), TD: tuber diameter (cm), TW: tuber weight (g), NTP: number of tubers plant−1, TPC: total phenolic content (mg 100 g−1 fresh tuber), Vit-C: vitamin C (mg 100 g−1 fresh tuber).
Figure 5. Biplot for morphological and biochemical traits of BAU sweetpotato-5. Here, NL 115 DAP: number of leaves 115 days after transplanting, VL115 DAP: vine length 115 days after transplanting, NB: number of branches, SD: stem diameter (cm), FWP: fresh weight plant−1 (g), TL: tuber length (cm), TD: tuber diameter (cm), TW: tuber weight (g), NTP: number of tubers plant−1, TPC: total phenolic content (mg 100 g−1 fresh tuber), Vit-C: vitamin C (mg 100 g−1 fresh tuber).
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Figure 6. Experimental set up (a), tuber growth under T1 (b) and collected tuber samples from three different treatments (c).
Figure 6. Experimental set up (a), tuber growth under T1 (b) and collected tuber samples from three different treatments (c).
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Table 1. Analysis of variance (mean squares) for morphological and biochemical traits of BAU sweetpotato-5.
Table 1. Analysis of variance (mean squares) for morphological and biochemical traits of BAU sweetpotato-5.
CharactersdfMean Squaresp Value
TreatmentErrorTreatmentError
Number of leaves30 DAP299.042.850.090
60 DAP109.7325.30.722
90 DAP6.141467.380.996
115 DAP112.31613.70.933
Vine length30 DAP3.0214.030.811
60 DAP315.0307.90.398
90 DAP496.8532.90.429
115 DAP215.2930.30.798
Number of branches0.640.520.335
Stem diameter0.020.0050.062
Fresh weight plant−171534*153120.041
Tuber length13.287.060.207
Tuber diameter2.0481.440.290
Tuber weight1431688650.252
Number of tuber plant−14.08 *0.940.048
SPAD85.23 *14.430.023
Total phenolic content36.334 *6.560.027
Vitamin C36.557 **2.210.001
Carotenoid0.0066 **0.000780.009
Anthocyanin2.121 **0.15350.002
Glucose0.632.040.741
Fructose2.231.300.233
Sucrose3.0032.1040.290
Zn9.99 ***0.135<0.001
Fe3819.53 ***1.37<0.001
*, **, and *** indicate significant at 5%, 1%, and 0.1% levels of probability, respectively. Here, df: degrees of freedom, DAP: days after transplanting.
Table 2. Coefficients of principal components for morphological and biochemical traits of BAU sweetpotato-5.
Table 2. Coefficients of principal components for morphological and biochemical traits of BAU sweetpotato-5.
VariablePC1PC2PC3
NL 115 DAP0.189−0.4210.154
VL 115 DAP0.238−0.2820.243
NB0.234−0.1610.421
SD0.2590.217−0.017
FWP0.355−0.0550.032
TL0.239−0.244−0.250
TD0.305−0.2280.104
TW0.306−0.212−0.019
NTP0.2230.228−0.286
SPAD0.259−0.019−0.270
TPC−0.1930.0580.246
Vit-C−0.250−0.1910.255
Carotenoid0.1960.3690.054
Anthocyanin0.3080.221−0.166
Zn−0.231−0.347−0.298
Fe0.1130.3360.515
% variation explained45.419.912.2
p value0.0070.0930.001
Here, NL 115 DAP: number of leaves 115 days after transplanting, VL115 DAP: vine length 115 days after transplanting, NB: number of branches, SD: stem diameter (cm), FWP: fresh weight plant−1 (g), TL: tuber length (cm), TD: tuber diameter (cm), TW: tuber weight (g), NTP: number of tuber plant−1, TPC: total phenolic content (mg 100 g−1 fresh tuber), Vit-C: vitamin C (mg 100 g−1 fresh tuber).
Table 3. Chemical properties of soil of Madhupur tract (Habibur et al. 2020).
Table 3. Chemical properties of soil of Madhupur tract (Habibur et al. 2020).
ParametersValues
pH6.5
Organic matter1.1%
N0.064%
K0.13 meq 100 g−1
P13.4 μg g−1
S13.3 μg g−1
Zn0.73 μg g−1
B0.17 μg g−1
Table 4. Dosages of MoP fertilizer imposed as three levels of treatments.
Table 4. Dosages of MoP fertilizer imposed as three levels of treatments.
TreatmentMoP Dosages
kg ha−1g plot−1
T0321.620
T1160.810
T2NoNo
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Sharmin, S.; Arfin, M.N.H.; Tareque, A.M.M.M.U.; Kafi, A.A.; Miah, M.S.; Hossen, M.Z.; Talukder, M.A.S.; Robin, A.H.K. Reduction of Potassium Supply Alters the Production and Quality Traits of Ipomoea batatas cv. BAU Sweetpotato-5 Tubers. Stresses 2024, 4, 883-895. https://doi.org/10.3390/stresses4040059

AMA Style

Sharmin S, Arfin MNH, Tareque AMMMU, Kafi AA, Miah MS, Hossen MZ, Talukder MAS, Robin AHK. Reduction of Potassium Supply Alters the Production and Quality Traits of Ipomoea batatas cv. BAU Sweetpotato-5 Tubers. Stresses. 2024; 4(4):883-895. https://doi.org/10.3390/stresses4040059

Chicago/Turabian Style

Sharmin, Shaila, Md. Nazmul Hasan Arfin, Abu Musa Md Main Uddin Tareque, Abdullah Al Kafi, Md. Shohidullah Miah, Md. Zakir Hossen, Md. Abdus Shabur Talukder, and Arif Hasan Khan Robin. 2024. "Reduction of Potassium Supply Alters the Production and Quality Traits of Ipomoea batatas cv. BAU Sweetpotato-5 Tubers" Stresses 4, no. 4: 883-895. https://doi.org/10.3390/stresses4040059

APA Style

Sharmin, S., Arfin, M. N. H., Tareque, A. M. M. M. U., Kafi, A. A., Miah, M. S., Hossen, M. Z., Talukder, M. A. S., & Robin, A. H. K. (2024). Reduction of Potassium Supply Alters the Production and Quality Traits of Ipomoea batatas cv. BAU Sweetpotato-5 Tubers. Stresses, 4(4), 883-895. https://doi.org/10.3390/stresses4040059

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