Sweet Potato Cultivars Research Articles

High-Density Single Nucleotide Polymorphisms Genetic Map Construction and Quantitative Trait Locus Mapping of Color-Related Traits of Purple Sweet Potato [Ipomoea batatas (L.) Lam.

Flesh color (FC), skin color (SC), and anthocyanin content (AC) are three important traits being used for commodity evaluation in purple-fleshed sweet potato. However, to date, only a few reports are available on the inheritance of these traits. In this study, we used a biparental mapping population of 274 F1 progeny generated from a cross between a dark purple-fleshed (Xuzishu8) and white-fleshed (Meiguohong) sweet potato variety for genetic analyses. Correlation analysis showed a significant positive correlation among AC, SC, and FC. Medium-to-high heritability was observed for these traits. We detected single nucleotide polymorphisms (SNPs) by specific length amplified fragment sequencing (SLAF-seq) with the average sequencing depth of 51.72 and 25.76 for parents and progeny, respectively. Then we constructed an integrated genetic map consisting of 15 linkage groups (LGS) of sweet potato spanning on 2,233.66 cm with an average map distance of 0.71 cm between adjacent markers. Based on the linkage map, ten major quantitative trait loci (QTLs) associated to FC, SC, and AC were identified on LG12 between 0 and 64.97 cm distance, such as one QTL for SC and FC, respectively, which explained 36.3 and 45.9% of phenotypic variation; eight QTLs for AC, which explained 10.5–28.5% of the variation. These major QTLs were highly consistent and co-localized on LG12. Positive correlation, high heritability, and co-localization of QTLs on the same LG group confirm the significance of this study to establish a marker-assisted breeding program for sweet potato improvement.

Effect of Processing Methods on Nutrient Contents of Sweet Potato (<i>Ipomoea batatas </i>(L.) Lam.) Varieties Grown in Ethiopia

Sweet potato [<i>Ipomoea batatas</i> (L.) Lam.] is an important crop farmed in most of southern and eastern Africa, including Ethiopia, and is utilized in agriculture, food, and other sectors. The objective of this study was to see how different processing methods (boiling, frying, roasting, and steaming) altered the proximate composition, vitamin C, and mineral content of four popular Ethiopian sweet potato cultivars: Tulla, kulfo, Hawassa 83, and Hawassa 09. UV-Vis and AAS methods were used to determine vitamin C and menial contents, respectively. AOAC methods were used to analyze the proximate composition. The results revealed that there were significant (p<0.05) differences in crude protein and CHO between cultivars. Total carbohydrate between varieties ranged from 45.49 to 89.28%, crude fiber (2.08 to 2.51%), crude protein (1.95 to 8.31%), fat (0.45 to 0.85%), ash (3.88 to 4.23%), and moisture (5.50 to 10.4%). Boiling, roasting, steaming, and frying sweet potato cultivars had no discernible effect on the crude protein and ash content. However, there was a statistically significant (p<0.05) difference in vitamin C levels between roasting and other processing methods. Furthermore, there is a significant variation in calcium and potassium levels (p<0.05) between the kinds. The findings revealed that there is no requirement to select processing methods that result in the least amount of nutritional loss. This means that the nutritional content of sweet potato types is better preserved after processing.

Performance of sweet potato genotypes in Brazilian regions

The average yield of sweet potato (Ipomoea batatas (L.) Lam.) in Brazil is below the crop potential, and appropriate cultural practices and more productive cultivars are needed to improve crop yield. The Beauregard sweet potato cultivar, originally from the United States, has shown high productive potential. This study evaluated the performance of features of agronomic importance of the Beauregard cultivar in comparison to local cultivars and eight sweet-potato clones in Brazilian regions. For that purpose, two sets of experiments were carried out. The first set evaluated eight sweet potato clones and cultivars Beauregard, Olho Roxo and Ourinhos in Brasília–DF and Itabaiana–SE using as criteria two foliage and six root traits. In the second set, two sweet potato clones (9 and 75), and Beauregard, Brazlândia Branca and Canadense cultivars were evaluated in Piacatú–SP, Brasília–DF, PAD–DF, Canoinhas–SC and Altamira–PA, for the traits: commercial, non-commercial, and total yield. Beauregard presented little foliage production but great root yield across the different environments. Since it has low dry matter content, acceptance of this cultivar may be limited in some regions. None of the sweet potato clones showed stable yield to justify a commercial launch.

Root Growth and Nitrate Absorption and Assimilation of Two Sweet Potato Cultivars with Different N Tolerances in Response to Nitrate Supply

Root Growth and Nitrate Absorption and Assimilation of Two Sweet Potato Cultivars with Different N Tolerances in Response to Nitrate Supply

Influence of Hot-water Treatment on the Trypsin Inhibitor Activity Reduction of Sweet Potatoes

HighlightsSweet potatoes designated for animals contains higher trypsin inhibitor activity.The trypsin inhibitor activity of sweet potatoes was reduced by hot-water treatment.The optimal conditions of hot-water treatment were determined to be 95°C and 14 min.Sweet potato extracts are reversible competitive trypsin inhibitors.ABSTRACT.Sweet potatoes are a good food source, but they contain trypsin inhibitors, which reduce the protein utilization rate in animals. This study analyzed the trypsin inhibitor activity of ten sweet potato varieties. Most of the sweet potatoes designated for animals exhibited high trypsin inhibitor activity. The trypsin activities of TNG57 and TNG10, the most popular sweet potato varieties in Taiwan, were 51.5% and 77.1%, respectively. However, the trypsin inhibitor activity of these fresh sweet potatoes was successfully reduced by hot-water treatment. The influence of hot-water temperature and treatment time was analyzed by response surface methodology (RSM). From the RSM regression models, the optimal conditions of hot-water treatment were determined to be 95°C and 14 min. The kinetic parameters (Km and Vmax) of sweet potato extracts were determined from a Lineweaver-Burke plot. The inhibitor in sweet potato extracts was classified as reversible competitive. Keywords: Hot-water treatment, Sweet potato, Trypsin inhibitor, Response surface methodology.

Assessment of the collection of sweet potato varieties (IPOMOEA BATATAS L.) in terms of suitability for cultivation and breeding in CRNZ

The article presents the results of a reconnaissance study of the suitability of sweet potato varieties collection for cultivation and breeding process in the conditions of the Central region of the Non-Chernozem zone. Sweet potato cuttings with 4-5 nodes were planted according to the scheme 70 x 40 cm with subsequent watering. During the growing season, sweet potato was watered as necessary. Each variant was tested in 4-fold repetition, 10 plants per plot. The varieties had a high variability of all economically useful traits within the repetitions. For most varieties, the sum of effective temperatures was not enough to accumulate a sufficient amount of plastic substances in the root tubers. As a result of our research, it was found that sweet potato varieties Vinnitskiy rozoviy and Manchzhurskiy are most suitable for cultivation in the CRNZ. They are characterized by a relatively high yield of commercial root tubers. The remaining varieties (Americanskiy begevy, Boregard, Yaponskiy, Germanskiy belyi and O'Henry) are not suitable for cultivation in this zone. Nevertheless, they are characterized by a high potential for the formation of root bulges, which can be used in sweet potato breeding. The possibility of breeding work with sweet potato in the conditions of the CRNZ is shown. Nevertheless, for successful work in this direction, it is necessary to use a greenhouse.

Comparative Transcriptome Analysis of Storage Root Reveals Regulatory Mechanisms of Lignin Biosynthesis During Root Development in Two Sweetpotato Cultivars

Comparative Transcriptome Analysis of Storage Root Reveals Regulatory Mechanisms of Lignin Biosynthesis During Root Development in Two Sweetpotato Cultivars

Performance Evaluation of Sweet Potato Varieties for Root Yield and Related Traits in South Gondar Zone, North West Ethiopia

A sweet potato production is not practiced in most parts of North Western Ethiopia mainly due to gap of knowledge and awareness about its production system and benefits; and shortage of improved varieties in the area. So that a study was conducted to overcome such challenges during 2019 main growing season at Dera and Libokemkem districts in North Western Ethiopia. The experiment included five white fleshed sweet potato improved varieties (Hawassa-09, Berkuma, Adu, Tola and Awassa-83). It was established in a randomized complete block design in three replications with the objective of testing the performance of the varieties for their adaptability and to recommend the superior ones for demonstrations on farmers’ plots. The results of analysis of root yield and most traits considered shown significant variation among varieties at both locations. The results further revealed that the interaction effects of genotypes by location were significant for most traits except root length, above ground fresh weight and number of roots per plant indicating the differential response of varieties for those traits at each location. Varieties Hawassa-09 and Burkuma gave superior storage root yield than the others at each location. Hence, these varieties need to be multiplication of seed/vines cutting materials and further demonstration for sustainable sweet potato production in the study areas.

DIAGNOSTIC OF THE CURRENT LIVELIHOOD EVOLUTION, FARMING PRACTICES, PRODUCTION CONSTRAINTS, POST-HARVEST PROCESSING, TRADING AND VALUE-CHAIN SYSTEMS OF SWEETPOTATO IN NORTH-KIVU PROVINCE, EASTERN OF DRCONGO

Although in many countries of Sub-Sahara Africa, sweet potato has been found to be very important for food security for farmers who depended on it for their livelihood, little documentation on the production constraints, preferences for sweetpotato genotypes by farmers, pre- and post-harvest handling and value chain issues were available for North-Kivu province. Hence, a survey assessment was conducted (March-December 2021) in major sweetpotato growing territories in North-Kivu province. Data was collected through field visits, semistructured interviews, focus group discussions and field observations after structured questionnaire have been administered to farmers. Descriptive statistics were applied to analyze the data. The results indicated that sweetpotato is grown by rural households for food and cash, and women play a major role in cultivating the crop. The crop was cultivated on small plots, mainly in upland areas, during the rainy season and sometimes in valley bottoms during dry season. Most farmers provide their own planting materials or obtained vines free from neighbours. Vines were usually planted on mounds. Ridges were used in highland areas in lieu of mounds as a way to control soil erosion/land slide impacts. Sweetpotato is commonly solecropped, although it is occasionally intercropped with beans, maize, banana, and other crops. Key attributes for maintenance of varieties were access to healthy planting material availability and distribution, tolerance abiotic stresses, resistance to biotic stresses, good taste and high root yield , early maturity, cookability, low perishability during storage. Piecemeal harvesting was common except when larger quantities are harvested for sale. During the harvest period, people consume sweetpotatoes every day and sometimes for every meal. Peeling &amp; boiling or steaming is the most common method of preparation. Pests and diseases were reported to be associated with severe and high yield loss although incidence of pests and diseases were of high seasonal variations. The overall identified factors constraining productivity included shortage of land and planting materials, landrace low yield, some variety high sensitivity to weeds, diseases and insect pests aggressions, inaccessibility to financial credits. Post-harvest and value chain constraints included: high labour and transport costs, poor access to markets &amp; low market prices, inaccessibility to improved varieties, a lack of knowledge on processing and equipment, packaging, marketing and transportation problems, inadequate extension services and postharvest losses. Farmers indicated that flood and landslide/soil erosion were serious abiotic stresses. The result showed that age, education level of household head, land and household sizes, input costs, livestock ownership, access to market information and to financial credit or extension services, output and sales revenue may have a significant impact on outcome and affect household gross margin. Thus, enhancing farmers’ access to market information, boosting the production and productivity of the crop through better extension services and infrastructures, awareness creation on gender balanced market engagement and improvement in transportation facilities are the critical points that should get policy attentions in the study area. Results of this study can serve as a baseline reference for strategic breeding and other interventions to develop sweetpotato varieties according to the needs of the farmers.

Effect of Quality Characteristics of Various Cultivars of Sweet Potato on Puree Viscosity

Effect of Quality Characteristics of Various Cultivars of Sweet Potato on Puree Viscosity

Particulate Matter (PM) Adsorption and Leaf Characteristics of Ornamental Sweet Potato (Ipomoea batatas L.) Cultivars and Two Common Indoor Plants (Hedera helix L. and Epipremnum aureum Lindl. &amp; Andre)

Particulate matter (PM) is a serious threat to human health, climate, and ecosystems. Furthermore, owing to the combined influence of indoor and outdoor particles, indoor PM can pose a greater threat than urban PM. Plants can help to reduce PM pollution by acting as biofilters. Plants with different leaf characteristics have varying capacities to capture PM. However, the PM mitigation effects of plants and their primary factors are unclear. In this study, we investigated the PM adsorption and leaf characteristics of five ornamental sweet potato (Ipomea batatas L.) cultivars and two common indoor plants (Hedera helix L. and Epipremnum aureum Lindl. &amp; Andre) exposed to approximately 300 μg m−3 of fly ash particles to assess the factors influencing PM adsorption on leaves and to understand the effects of PM pollution on the leaf characteristics of plants. We analyzed the correlation between PM adsorption and photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), leaf area (LA), leaf width/length ratio (W/L), stomatal density (SD), and stomatal pore size (SP). A Pearson’s correlation analysis and a principal component analysis (PCA) were used to evaluate the effects of different leaf characteristics on PM adsorption. The analysis indicated that leaf gas exchange factors, such as Pn and Tr, and morphological factors, such as W/L and LA, were the primary parameters influencing PM adsorption in all cultivars and species tested. Pn, Tr, and W/L showed a positive correlation with PM accumulation, whereas LA was negatively correlated.

The Growth and Production of Three Sweet Potato Varieties as Affected by Dosage of Potassium Fertlizer on the Ultisols of Bengkulu Province

This study aims to study the interaction between varieties and the correct dose of potassium fertilizer, determine the right dose of potassium fertilizer and the appropriate variety of sweet potato in Ultisol. In this study, the research design used was a completely randomized block design (RAKL) with two (2) factors with three replications. The first factor is three varieties of sweet potato, namely Cilembu, Atin 3, and Beta 1. The second factor is the dose of KCl fertilizer which consists of 4 levels of dosage, namely 0 kg ha-1, 150 kg ha-1, 300 kg ha-1, and 450 kg ha-1 KCl fertilizer. The results showed no significant interaction between the dose of KCl fertilizer and the three varieties of sweet potato. The Antin 3 variety produced the most extended tendril length compared to the other two varieties. The lowest number of branches was produced by Beta 1 variety. The Cilembu variety produced the most significant tuber weight per plot and estimated weight per plot. The Cilembu variety is proven to have the highest level of sweetness.

Production of Agrocinopine A by Ipomoea batatas Agrocinopine Synthase in Transgenic Tobacco and Its Effect on the Rhizosphere Microbial Community.

Agrobacterium tumefaciens is a bacterial pathogen that causes crown gall disease on a wide range of eudicot plants by genetic transformation. Besides T-DNA integrated by natural transformation of plant vegetative tissues by pathogenic Agrobacterium spp., previous reports have indicated that T-DNA sequences originating from an ancestral Agrobacterium sp. are present in the genomes of all cultivated sweet potato (Ipomoea batatas) varieties analyzed. Expression of an Agrobacterium-derived agrocinopine synthase (ACS) gene was detected in leaf and root tissues of sweet potato, suggesting that the plant can produce agrocinopine, a sugar-phosphodiester opine considered to be utilized by some strains of Agrobacterium spp. in crown gall. To validate the product synthesized by Ipomoea batatas ACS (IbACS), we introduced IbACS into tobacco under a constitutive promoter. High-voltage paper electrophoresis followed by alkaline silver nitrate staining detected the production of an agrocinopine-like substance in IbACS1-expressing tobacco, and further mass spectrometry and nuclear magnetic resonance analyses of the product confirmed that IbACS can produce agrocinopine A from natural plant substrates. The partially purified compound was biologically active in an agrocinopine A bioassay. A 16S ribosomal RNA amplicon sequencing and meta-transcriptome analysis revealed that the rhizosphere microbial community of tobacco was affected by the expression of IbACS. A new species of Leifsonia (actinobacteria) was isolated as an enriched bacterium in the rhizosphere of IbACS1-expressing tobacco. This Leifsonia sp. can catabolize agrocinopine A produced in tobacco, indicating that the production of agrocinopine A attracts rhizosphere bacteria that can utilize this sugar-phosphodiester. These results suggest a potential role of IbACS conserved among sweet potato cultivars in manipulating their microbial community.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Yield and Profitability of Newly Recommended Sweetpotato (Ipomoea batatas (L.) Lam) NSIC Sp36 Variety as Affected by Planting Density

Appropriate planting density is necessary to achieve high crop productivity. Hence, this study aimed to determine the optimum planting density and assess the profitability per hectare of NSIC's newly recommended sweetpotato variety. The treatments were as follows: T 1.0 m x 0.50 m at two cuttings per hill, T-1.0 m x 0.25 12 m at one cutting per hill, T- 1.0 m x 0.25 m at two cuttings per hill, T-1.0m x 0.30m at 3 4 one cutting per hill, and T-1.0 m x 0.30 m at two cuttings per hill. The experiment 5 was laid out in Randomized Complete Block Design (RCBD) with three replications. The results revealed that sweetpotato planted at wider spacing of 1.0 m x 0.50 m at two cuttings per hill produced more primary lateral vines (7.13), bigger leaf area -1 index (4.29), fresh herbage weight (21.22 tha ), and highest weight (g) of marketable roots per hill. On the other hand, planting density of 1.0 m x 0.25 m at one and two cuttings per hill obtained the highest weight of total root yield at 13.43 t ha -1 -1 and 14.04 t ha respectively. Likewise, sweetpotato grown in 1.0 m x 0.25 m at one -1 cutting per hill obtained the highest gross margin of PhP160,240.00 ha due to higher root yield and less cost of planting materials. This was followed by plants planted in 1.0 m x 0.25 m at two cuttings per hill with PhP159,702.00 ha .

Comparative Study of Potato (Solanum tuberosum L.) and Sweet Potato (Ipomoea batatas L.): Evaluation of Proximate Composition, Polyphenol Content, Mineral and Antioxidant Activities

The objective of the present study was to differentiate and compare the proximate composition, minerals, flesh colour, phenolic composition, and antioxidant activities of varieties of white-fleshed sweet potato (WFSP) and potato (WFP) locally grown in Pakistan. The results showed that WFP presented higher moisture and crude fat content, while WFSP offered better ash, crude protein, and crude fibre contents. Colour analysis revealed that WFSP and WFP showed the highest L* (lightness) values and exhibited the maximum total phenolic content and total flavonoids content of 9.27 ± 0.88 mg GAE/g and 19.01 ± 0.66 mg QE/g. In vitro, results demonstrated that WFSP possessed better antioxidant activity with the highest ferric reducing antioxidant power of 58.67 ± 0.22 mM Fe2+/g and DPPH scavenging activity of 39.12 ± 0.33% compared to WFP. It is concluded that WFSP possesses a better proximate and mineral profile followed by higher antioxidant activity.

PERBEDAAN KADAR ANTOSIANIN UBI UNGU SEGAR DAN TEPUNG UBI UNGU VARIETAS LOKAL DAN ANTIN 3 PADA BEBERAPA ALAT PENGERINGAN

Background: Purple sweet potato is one of the local Asian food ingredients known as "people's food". Purple sweet potato is rich in anthocyanins which function as antioxidants and immunonutrients. In addition to being widely used as food or traditional snacks, purple sweet potato can be used as a functional food ingredient rich in anthocyanins. For example, purple sweet potato flour can be used as an essential ingredient for processed foods.Objectives: To analyze differences in anthocyanin levels in fresh purple sweet potato local varieties of Gunung Kawi and Antin 3 and purple sweet potato flour with different drying tools.Methods: This research consist of two research stages. The first phase analyzes differences in anthocyanin content in fresh purple sweet potatoes local varieties of Gunung Kawi and Antin 3 with a RAL research design (Completely Randomized Design) 3 repetitions. Then, the second stage of the research used a one-shot case study with 3 treatment groups: drying with an electric oven, cabinet dryer, and food dehydrator. Anthocyanin levels were tested using the UV-Vis spectrophotometry method. Differences in fresh purple sweet potato anthocyanins were analyzed using an independent t-test. Meanwhile, the different anthocyanin levels of purple sweet potato flour were analyzed using one-way ANOVA.Results: The first stage of the study showed that the anthocyanin content of fresh purple sweet potato Antin 3 was seven times higher than that of Gunung Kawi (53.94±25.6 v.s 7.59±2.4 mg/100 g) with p=0.036. The second stage of the study, showed no statistically significant difference in anthocyanin levels (p = 0.066) in 3 different drying equipment.Conclusion: Antin 3 purple sweet potato variety is purple sweet potato with the highest anthocyanin content. The purple sweet potato flour was dried with 3 different drying tools, resulting in anthocyanin levels that were not significantly different.Keywords: Anthocyanin; Gunung Kawi local purple sweet potato; Antin 3 purple sweet potato; Purple sweet potato flour; Drying equipment

An Evaluation of Phenolic Compounds, Carotenoids, and Antioxidant Properties in Leaves of South African Cultivars, Peruvian 199062.1 and USA's Beauregard.

In this study, leaves of sweet potato cultivars from South Africa (“Ndou,” “Bophelo,” “Monate,” and “Blesbok”), “Beauregard,” a sweet potato cultivar from the USA, and a Peruvian cultivar “199062. 1” were analyzed using UPLC/QTOF/MS and chemometrics, with the aim of characterizing the locally developed sweet potato cultivars and comparing them with already well-known established varieties on the market. A set of 13 phenolic compounds was identified. A partial least squares discriminant analysis, a hierarchical cluster analysis, and variables importance in projection were used to successfully distinguish sweet potato varieties based on their distinct metabolites. Caffeic acid enabled to distinguish Cluster 1 leaves of varieties (“Beauregard” and “Ndou”) from Cluster 2 (“199062.1,” “Bophelo,” “Monate,” and “Blesbok”). The leaves of “Bophelo” contained the highest concentrations of rutin, quercetin 3-O-galactoside, 3-caffeoylquinic acid (3-CQA), (5-CQA), 1,3 dicaffeoylquinic acid (1,3-diCQA), 1,4-diCQA, and 3,5-diCQA. Furthermore, Bophelo leaves showed the highest antioxidant activities (FRAP 19.69 mM TEACg−1 and IC50 values of (3.51 and 3.43 mg ml−1) for DPPH and ABTS, respectively, compared to the other varieties. Leaves of “Blesbok” contained the highest levels of β-carotene (10.27 mg kg−1) and zeaxanthin (5.02 mg kg−1) on a dry weight basis compared to all other varieties. This study demonstrated that the leaves of local cultivars “Bophelo” and “Blesbok” have the potential to become functional ingredients for food processing.

Effects of Variety and Growing Location on Physicochemical Properties of Starch from Sweet Potato Root Tuber.

Three sweet potato varieties with purple-, yellow-, and white-fleshed root tubers were planted in four growing locations. Starches were isolated from their root tubers, their physicochemical properties (size, iodine absorption, amylose content, crystalline structure, ordered degree, lamellar thickness, swelling power, water solubility, and pasting, thermal and digestion properties) were determined to investigate the effects of variety and growing location on starch properties in sweet potato. The results showed that granule size (D[4,3]) ranged from 12.1 to 18.2 μm, the iodine absorption parameters varied from 0.260 to 0.361 for OD620, from 0.243 to 0.326 for OD680 and from 1.128 to 1.252 for OD620/550, and amylose content varied from 16.4% to 21.2% among starches from three varieties and four growing locations. Starches exhibited C-type X-ray diffraction patterns, and had ordered degrees from 0.634 to 0.726 and lamellar thicknesses from 9.72 to 10.21 nm. Starches had significantly different swelling powers, water solubilities, pasting viscosities, and thermal properties. Native starches had rapidly digestible starch (RDS) from 2.2% to 10.9% and resistant starch (RS) from 58.2% to 89.1%, and gelatinized starches had RDS from 70.5% to 81.4% and RS from 10.8% to 23.3%. Two-way ANOVA analysis showed that starch physicochemical properties were affected significantly by variety, growing location, and their interaction in sweet potato.

Storage Property Is Positively Correlated With Antioxidant Capacity in Different Sweet Potato Cultivars.

Sweet potato decays easily due to its high respiration rate and reactive oxygen species (ROS) accumulation during postharvest storage. In this study, we explored the relationship between antioxidant capacity in leaves and storage properties in different sweet potato cultivars, the tuberous roots of 10 sweet potato cultivars were used as the experimental materials to analyze the storage property during storage at 11–15°C. According to the decay percentage after 290 days of storage, Xu 32 was defined as a storage-tolerant cultivar (rot percentage less than 25%); Xu 55-2, Z 15-1, Shangshu 19, Yushu, and Zhezi 3 as above-moderate storage-tolerant cultivars (rot percentage ranging from 25 to 50%); Sushu 16, Yanshu 5, and Hanzi as medium-storable cultivars (rot percentage 50–75%); and Yan 25 as a storage-sensitive cultivar (rot percentage greater than 75%). Meanwhile, analysis of the α-amylase activity in root tubers of the 10 sweet potato cultivars during storage indicated that α-amylase activity was lowest in the storage-tolerant cultivar Xu 32 and highest in the storage-sensitive cultivar Yan 25. Evaluation of antioxidant enzyme activities and ROS content in the leaves of these 10 cultivars demonstrated that cultivar Xu 32, which showed the best storage property, had higher antioxidant enzyme activity [superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD)] but lower lipoxygenase (LOX) activity, hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents, and superoxide anion radical (O2⋅–) production rates compared with those of the storage-sensitive cultivar Yan 25 and the medium-storability cultivars Hanzi, Yanshu 5, and Sushu 16. Additionally, principal component analysis (PCA) suggested that sweet potato cultivars with different storage properties were clustered separately. Correlation and heat map analysis further indicated that CAT, APX, POD, and SOD activities were negatively correlated with α-amylase activity, while LOX activity and MDA and H2O2 contents were negatively correlated with the storage property of sweet potato. Combined, our findings revealed that storage property is highly correlated with antioxidant capacity in sweet potato leaves and negatively correlated with α-amylase activity in tuberous roots, which provides a convenient means for the screening of storage-tolerant sweet potato cultivars.

Comparative analysis of nutrient composition and glycaemic indices of nine sweet potatoes (Ipomoea batatas) varieties

Sweet potatoes are one of the major tuberous roots consumed around the world. The objective of the present study was to determine the nutritional composition, glycaemic indices and glycaemic loads of selected Sri Lankan sweet potato varieties, in order to address the inadequacy of information and the controversial findings on glycaemic indices. Nutrient composition (moisture, ash, digestible carbohydrates, dietary fiber, crude protein and fat) of boiled sweet potatoes, GI and glycaemic loads (GL) of nine varieties were determined using standard methods. Digestible carbohydrate content ranged between 29-88% on dry weight. Ash, crude protein and crude fat contents of the varieties ranged between 3.1-5.0%, 3.0-5.9% and 2.6-5.3% on dry weight basis (DW) respectively. The total dietary fiber content was above 9.5% DW in the studied varieties. Moisture content of boiled sweet potato tubers were 72-81% on fresh weight basis and both the GIs (86-119) and GLs (&gt;20) were high. However, the GL reduced to medium or low when considering an actual edible portion for all the varieties except for two varieties. Sweet potatoes are a good source of highly available carbohydrates which elicit high GIs.