Sweet Potato Cultivars Research Articles

Indonesian market demand patterns for food commodity sources of carbohydrates in facing the global food crisis

Global food consumption tends to rise more quickly than supply. This has to do with important global issues like population growth. Additionally, global conflicts are going to hinder the distribution of food. Indonesia has an enormous opportunity of anticipating these circumstances considering its promise as one of the largest supplies of food worldwide. Rice is still the staple food in Indonesia, but the dynamics of society are under threat from wheat food. It is possible to create strategy plans to deal with potential food scarcity by understanding the behavior of food demand trends for big carbohydrate sources like corn, cassava, sweet potatoes (as a substitution), and the development of wheat as a beneficial food. The results of the study indicate that rice, corn, cassava, and sweet potatoes—food commodities that are major sources of carbohydrates—are inelastic, which means that their prices are not affected by variations in demand. The community still relies on rice as the primary food source. Cross elasticity >0 in these non-wheat food commodities indicates mutually beneficial replacement among the foods that are sources of carbohydrates. That is, with the dynamics of an increase in income, for example, it will also increase consumption. The results of the study also demonstrate that wheat food items are only a complementary, not a staple food needed, thus concerns about wheat's dominance as a food component in industrial products actually have no impact on local food. The availability of high-yielding varieties of rice, corn, cassava, and sweet potatoes, the implementation of food reserves by the Indonesian National Logistics Agency (Bulog) from the government center to the regions, food diversification, changing preferences, and creating an awareness of local food pride with massive education are some of the anticipatory steps taken in response to the global food crisis.

Differential Responses of Antioxidant Enzymes and Lignin Metabolism in Susceptible and Resistant Sweetpotato Cultivars during Root-Knot Nematode Infection.

Root-knot nematodes (RKN) cause significant damage to sweetpotato plants and cause significant losses in yield and quality. Reactive oxygen species (ROS) play an important role in plant defenses, with levels of ROS-detoxifying antioxidant enzymes tightly regulated during pathogen infection. In this study, ROS metabolism was examined in three RKN-resistant and three RKN-susceptible sweetpotato cultivars. The antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were assessed, as was lignin-related metabolism. In RKN-infected roots, both resistant and susceptible cultivars increased SOD activity to produce higher levels of hydrogen peroxide (H2O2). However, H2O2 removal by CAT activity differed between cultivars, with susceptible cultivars having higher CAT activity and lower overall H2O2 levels. In addition, the expression of phenylpropanoid-related phenylalanine ammonia-lyase and cinnamyl alcohol dehydrogenase genes, which encode enzymes involved in lignin metabolism, were higher in resistant cultivars, as were total phenolic and lignin contents. Enzyme activities and H2O2 levels were examined during the early (7 days) and late (28 days) phases of infection in representative susceptible and resistant cultivars, revealing contrasting changes in ROS levels and antioxidant responses in the different stages of infection. This study suggests that differences in antioxidant enzyme activities and ROS regulation in resistant and susceptible cultivars might explain reduced RKN infection in resistant cultivars, resulting in smaller RKN populations and overall higher resistance to infection and infestation by RKNs.

Salinity Stress Effects on the Growth Yield and Quality Performance of Two Sweet Potato Varieties

The yield response of several sweet potato varieties to salinity stress has been extensively studied in the scientific literature, but no research on the Koganesengan and Beniazuma varieties has been identified. The purpose of this study was to examine the effects of various irrigation salinity levels on the growth (vine and tuber lengths, stem and tuber diameters, and number of leaves, shoots, and tubers), yield (fresh, dry, tuber, and total yields, and water use efficiencies for vine, tuber, and total yields), and quality parameters (dry matter, ash, crude fiber, starch, phenolic matter, antioxidant activity, ß-carotene, ascorbic acid, protein, saccharose, glucose, and fructose contents) of these sweet potato varieties under drip irrigation. The findings show that without a varietal difference, increasing water salinity levels increased soil salinity and decreased soil pH values. Some growth and yield parameters of “Beniazuma” were negatively affected by the salinity level, but not those of “Koganesengan”. Irrigation salinity levels only had an effect on the crude fiber content and antioxidant activity of “Koganesengan” and the ash, starch, ß-carotene, and ascorbic acid contents of “Beniazuma”. Significant variations between varieties were only seen under the control treatment for all yield parameters (except dry vine yield) and water use efficiency values. According to the calculated salinity threshold and slope values, “Beniazuma” is more sensitive to salt stress than “Koganesengan”.

Integrated Transcriptome and Metabolome Analyses Reveal Details of the Molecular Regulation of Resistance to Stem Nematode in Sweet Potato.

Stem nematode disease can seriously reduce the yield of sweet potato (Ipomoea batatas (L.) Lam). To explore resistance mechanism to stem nematode in sweet potato, transcriptomes and metabolomes were sequenced and compared between two sweet potato cultivars, the resistant Zhenghong 22 and susceptible Longshu 9, at different times after stem nematode infection. In the transcriptional regulatory pathway, mitogen-activated protein kinase signaling was initiated in Zhenghong 22 at the early stage of infection to activate genes related to ethylene production. Stem nematode infection in Zhenghong 22 also triggered fatty acid metabolism and the activity of respiratory burst oxidase in the metabolic pathway, which further stimulated the glycolytic and shikimic pathways to provide raw materials for secondary metabolite biosynthesis. An integrated analysis of the secondary metabolic regulation pathway in the resistant cultivar Zhenghong 22 revealed the accumulation of tryptophan, phenylalanine, and tyrosine, leading to increased biosynthesis of phenylpropanoids and salicylic acid and enhanced activity of the alkaloid pathway. Stem nematode infection also activated the biosynthesis of terpenoids, abscisic acid, zeatin, indole, and brassinosteroid, resulting in improved resistance to stem nematode. Finally, analyses of the resistance regulation pathway and a weighted gene co-expression network analysis highlighted the importance of the genes itf14g17940 and itf12g18840, encoding a leucine-rich receptor-like protein and 1-aminocyclopropane-1-carboxylate synthase, respectively. These are candidate target genes for increasing the strength of the defense response. These results provide new ideas and a theoretical basis for understanding the mechanism of resistance to stem nematode in sweet potato.

Effect of Growth Stages on Anthocyanins and Polyphenols in the Root System of Sweet Potato.

The storage roots of purple-fleshed sweet potato contain a variety of anthocyanins and polyphenols. Little is known about changes in the total content and composition of anthocyanins and polyphenols in the early growth stages of the root system. In this study, we investigated the changes in anthocyanins and polyphenols in the root system of purple-fleshed sweet potato cultivars at 15, 30, 45, and 60 days after transplant (DAT). Unexpectedly, the highest percentage of acylated anthocyanins in three purple-fleshed cultivars among all growth stages was at 15 DAT. On the other hand, the total polyphenol content in the early growth stages of the root system increased rapidly toward 45 DAT, just before the beginning of storage root enlargement, and then decreased rapidly as the storage roots began to enlarge. These data indicate that the early growth stage of the root system is a critical time. This timing may present a strategy to maximize the accumulation of polyphenols with high antioxidant activity, as well as acylated anthocyanins, to protect against abiotic and biotic stresses.

Evaluating the Effects of Sweet Potato Varieties on Flour Quality

Evaluating the Effects of Sweet Potato Varieties on Flour Quality

Evaluating the Effects of Sweet Potato Varieties on Flour Quality

Evaluating the Effects of Sweet Potato Varieties on Flour Quality

Influence of plant covering with nonwoven agrotextile on the vegetative growth characteristics and yield of sweet potato (Ipomoea batatas L.): A Slovenian case study

The objective of this study was to evaluate the impact of cultivar and covering with nonwoven agrotextile on vegetative growth parameters and the productivity value of sweet potato (Ipomoea batatas L.). A field experiment was conducted during the 2018 growing season, at the experimental field of the Biotechnical Faculty in Ljubljana (46° 04′ N latitude; 14° 31′ E longitude, 305 m above sea level). The soil was gravel clay with a pH of 6.7, and a soil depth of 40–60 cm. The research involved the following Slovenian cultivars of sweet potatoes: Lučka, Janja, and Martina. Distance between rows was 1.2 m, while in-row distance was 1.4 m. The experiment was conducted in a randomized complete block design with plots arranged factorially and replicated four times. The seedlings were planted on 20 May. A half of the plots were covered with polypropylene nonwoven textile (17 g/m2). The uncovered half of the plots served as control plots. The recommended cultural practices were performed as needed during the experiment. The temperature under the covers was on average 5.5 °C higher than in the unprotected area. The crops were harvested 132 days after planting. Covering significantly and positively affected vegetative growth – that is the height of the vines, leaf number, leaf area index, and haulm dry weight. In contrast, the nonwoven polypropylene cover had no significant effect on the number of branches per crop. The use of agrotextile significantly increased tuber length and diameter, tuber number, tuber weight, and total yield in comparison with traditional cultivation with no plant cover. Statistical analysis showed that cv. Janja had the significantly higher yield (7.49 t/ha) compared to cv. Lučka (6.68 t/ha) and cv. Martina (6.16 t/ha).

Integrating weed-suppressive cultivar and cover crops for weed management in organic sweetpotato production

AbstractField studies were conducted in 2021 in Kibler and Augusta, AR, to determine the effect of winter cover crops and cultivar selection on weed suppression and sweetpotato [Ipomoea batatas (L.) Lam.] yield. The split-split-plot studies evaluated three cover crops [cereal rye (Secale cereale L.) + crimson clover (Trifolium incarnatum L.)], [winter wheat (Triticum aestivum L.) + crimson clover], and fallow; weeding (with or without); and four sweetpotato cultivars (‘Heartogold’, ‘Bayou-Belle-6’, ‘Beauregard-14’, and ‘Orleans’). Heartogold had the tallest canopy, while Beauregard-14 and Bayou Belle-6 had the longest vines at 5 and 8 wk after sweetpotato transplanting. Sweetpotato canopy was about 20% taller in weedy plots compared with the hand-weeded treatment, and vines were shorter under weed interference. Canopy height and vine length of sweetpotato cultivars were not related to weed biomass suppression. However, vine length was positively correlated to all yield grades (r > 0.5). Weed biomass decreased 1-fold in plots with cover crops compared with bare soil at Augusta. Cover crop biomass was positively correlated with jumbo (r = 0.29), no. 1 (r = 0.33), and total sweetpotato yield (r = 0.34). Jumbo yield was affected the most by weed pressure. On average, sweetpotato total yield was reduced by 80% and 60% with weed interference in Augusta and Kibler, respectively. Bayou Belle-6 was the high-yielding cultivar without weed interference in both locations. Bayou Belle-6 and Heartogold were less affected by weed interference than Beauregard-14 and Orleans.

Potential of New Varieties of Sweet Potato Released By Indonesian Legumes and Tuber Crops Research Institute (ILETRI): A Preliminary Study

Sweet potato are potential to be utilized as replacer or substitution agent for rice for Indonesian. It provides some good nutrients to maintain healthy degree. It has a high energy content, protein, fat, and a considerable dietary fiber. Four of sweet potato varieties (i.e. Beta 1, Beta 2, Antin 2, Antin 3) contain bioactive compounds such as anthocyanin and beta-carotene. Beta 1 sweet potato had more beta carotene (13.01±1.73 mg/100g) than Beta 2 (5.96±0.44 mg/100g), while Antin 2 had less anthocyanin (32.18±0.01mg/100g) than Antin 3 (35.24±0.1 mg/100g). Nevertheless, Antin 2 contained highest protein (0.81±0.02%) among others. Moreover, Antin 2 and Antin 3 contained higher calories and dietary fiber compared to Beta 1. The lower content of these compounds in Beta variety might be attributed to the higher moisture content of Beta 1 (80.11±0.14%) and Beta 2 (77.40±0.45%), while the moisture content of Antin 2 and Antin 3 were 71.40±0.08% and 70.25±0.25%, respectively. In terms of sweet potato flour, Beta 1 had also more beta carotene (29.41±0.06 mg/100g) than Beta 2 (27.26±0.13 mg/100g), and Antin 3 contained more anthocyanin (47.66±0.05 mg/100g) than Antin 2 (29.04±0.01mg/100g). As for food product, macaroni had been made from flour and pasta of sweet potato. The sensory evaluation demonstrated that the products were well-accepted by the panelists in terms of color, flavor, taste, texture, and overall acceptability, indicating that sweet potato have a potential as food raw material and further utilization to support sustainable agriculture.

Characterization of sprayable mulch film from yam nagara starch for agricultural application

The conventional mulch film generally produced from plastic to control of weed in agriculture activities. Nevertheless, the used of conventional mulch film has impact to pollute the environment, due to non-degradable. Therefore, mulch film from natural material derived yam nagara starch can be alternative to substitute the conventional mulch film that more eco-friendly. The aims of this study are to fabricate and characterization of mulch film from yam nagara starch which prepared by sprayed technique. The yam nagara starch prepared from local sweet potato varieties (Ipomoea batatas L) of Nagara, South Kalimantan. Fabrication of mulch film was conducted by mixed yam nagara starch with varied composition (0.25-0.75 wt%), hydrolysed keratin of chicken feather, corn gluten meal (CGM), acetate acid, and carbon black. The final solution of yam nagara mulch film was applied on top soil as plant medium using compressor spray gun and left to dry for 24 h. Furthermore, the sprayable mulch films were characterized by several parameters i.e., FTIR, water solubility, water uptake, tensile strength and elongation. Sprayable mulch film from yam nagara starch were successfully fabricated for agriculture application. The results show the sprayable mulch film with composition of 0.75 wt% yam nagara starch obtain a good plastic-like characteristics and may be affordable to be degraded due to easily to can soluble with water and high-water uptake properties. In other hand, sprayable mulch film from yam nagara starch in this work affordable to restrains weeds of the chilli plants for agriculture application.

The Role of IAA in Regulating Root Architecture of Sweetpotato (Ipomoea batatas [L.] Lam) in Response to Potassium Deficiency Stress.

Plants can adapt to the spatial heterogeneity of soil nutrients by changing the morphology and architecture of the root system. Here, we explored the role of auxin in the response of sweetpotato roots to potassium (K+) deficiency stress. Two sweetpotato cultivars, Xushu 32 (low-K-tolerant) and Ningzishu 1 (low-K-sensitive), were cultured in low K+ (0.1 mmol L-1, LK) and normal K+ (10 mmol L-1, CK) nutrient solutions. Compared with CK, LK reduced the dry mass, K+ content, and K+ accumulation in the two cultivars, but the losses of Xushu 32 were smaller than those of Ningzishu 1. LK also affected root growth, mainly impairing the length, surface area, forks number, and crossings number. However, Xushu 32 had significantly higher lateral root length, density, and surface area than Ningzishu 1, closely related to the roots' higher indole-3-acetic acid (IAA) content. According to the qPCR results, Xushu 32 synthesized more IAA (via IbYUC8 and IbTAR2) in leaves but transported and accumulated in roots through polar transport (via IbPIN1, IbPIN3, and IbAUX1). It was also associated with the upregulation of auxin signaling pathway genes (IbIAA4 and IbIAA8) in roots. These results imply that IAA participates in the formation of lateral roots and the change in root architecture during the tolerance to low K+ stress of sweetpotato, thus improving the absorption of K+ and the formation of biomass.

Metabolic profiles and morphological characteristics of leaf tips among different sweet potato (Ipomoea batatas Lam.) varieties

Sweet potato leaf tips have high nutritional value, and exploring the differences in the metabolic profiles of leaf tips among different sweet potato varieties can provide information to improve their qualities. In this study, a UPLC-Q-Exactive Orbitrap/MS-based untargeted metabolomics method was used to evaluate the metabolites in leaf tips of 32 sweet potato varieties. Three varieties with distinct overall metabolic profiles (A01, A02, and A03), two varieties with distinct profiles of phenolic acids (A20 and A18), and three varieties with distinct profiles of flavonoids (A05, A12, and A16) were identified. In addition, a total of 163 and 29 differentially expressed metabolites correlated with the color and leaf shape of sweet potato leaf tips, respectively, were identified through morphological characterization. Group comparison analysis of the phenotypic traits and a metabolite-phenotypic trait correlation analysis indicated that the color differences of sweet potato leaf tips were markedly associated with flavonoids. Also, the level of polyphenols was correlated with the leaf shape of sweet potato leaf tips, with lobed leaf types having higher levels of polyphenols than the entire leaf types. The findings on the metabolic profiles and differentially expressed metabolites associated with the morphology of sweet potato leaf tips can provide useful information for breeding sweet potato varieties with higher nutritional value.

Effect of Fertilization Level on the Yield, Carotenoids, and Phenolic Content of Orange- and Purple-Fleshed Sweet Potato

Maintaining a diverse diet is essential for the preservation of one’s health and may contribute to the fight against significant civilization diseases such as obesity or diabetes. Sweet potato can be fitted into a diverse diet and serve as a functional food with its antioxidant content. Therefore, it is important to know how the production technology alters the content and composition of these antioxidant compounds. The objective of this study was to collect information on how the increased potassium dominant fertilizer levels and also the additional high-dose fertigation can affect the phytonutrient contents and yields in an orange- and a purple-fleshed sweet potato cultivar. Field experiments were conducted in the Hungarian county of Heves in two consecutive growing seasons in 2021–2022. Different doses of potassium-predominant fertilizer were applied to an orange flesh (Beauregard) and a purple flesh (Stokes Purple) varieties of sweet potatoes. Different application techniques were used in the form of base and top dressing at different rates. The effect on yield and polyphenol content of the different fertilizer rates was investigated. Analytical studies were carried out by high-performance liquid chromatography (HPLC). In the case of the Beauregard variety, in addition to identifying the carotenoids, we also performed their quantitative determination. We found that 87% of the carotenoid content was ß-carotene. The total anthocyanin content was investigated for the purple variety—Stokes Purple, for which a new extraction method was developed. In our study, the split dosages, when the pre-planting fertilizer was supplemented with additional liquid fertilization, resulted in 36 and 30.5% higher yields in the Beauregard in Experiment I and Experiment II, respectively, compared to the untreated control plots over the two years. The additional liquid fertilizer increased the yield to a lesser extent when compared to treatments received only pre-planting fertilizer. As for Experiment III, the split dosages resulted in 34.4% higher yields in the Stokes Purple compared to the control plots. However, the additional liquid fertilizer was not effective at all when the plants received a double dose of pre-planting fertilizer in the case of Stokes Purple. Total carotenoid (Experiment I–II) was higher and anthocyanin yield per plant (Experiment III) was significantly higher in the split-dosage treatment than in the untreated control plots.

Selection of new sweetpotato hybrids for West Africa using accelerated breeding scheme and genotype × environment interaction under drought stress

West Africa is a dry region and drought tolerant sweetpotato cultivar was not reported. The objective of this study was to develop higher yielding drought tolerant sweetpotato hybrids following accelerated breeding scheme (ABS), and study G × E interaction. During advanced yield trial, the assessment of clones was conducted in six locations: four in Niger and two in Nigeria. Data were collected on storage root yield (SRY), harvest index (HI) and root dry matter content (DMC). Twenty-three hybrids were evaluated under drought and irrigation. Terminal drought was imposed. SAS and GenStat softwares were used for analyses. Based on drought susceptibility index (DSI), drought tolerant expression (DTE) and HI, clones 4 × 5 – 3, 9 × 7 – 1, 5 × 9 – 2, 3 × 6 – 2, and 3 × 12 – 3 were the best in SRY under drought stress and well-watered in combined data. Using AMMI stability value (ASV) and stability cultivar superiority (SCS), results revealed that the most superior cultivars were unstable. Clones 12 × 5 – 1 and 9 × 10 – 1 were recommended under drought for SRY stability combined with high DMC and high total carotene (TC). Under irrigation, the 13 × 8 – 2 is good candidate for stability across all locations combined with high DMC and medium TC, while clone 4 × 3 – 2, 13 × 8 – 2, 4 × 6 – 2 and 6 × 8 – 5 were stable SRY with high DMC. Therefore, these hybrids could be evaluated at on-farm trials to release the best to farmers.

Development of control strategies for bacteria and fungi associated with a micropropagated new cultivar of orange-fleshed sweet potato (Ipomoea batatas cv. Agrosavia–Aurora)

Vegetative propagation of sweet potato lead to the accumulation of diseases from generation to generation, which represents a threat to both productivity and conservation of genetic resources. In vitro techniques can help to overcome phytosanitary problems by applying plant material cleaning strategies. The objective of this study was to develop in vitro micropropagation strategies for the production of high-quality plant material of an orange-fleshed variety of sweet potato recently released in Colombia. Molecular identification of contaminating microorganisms was performed by sequencing the 16S rRNA gene for bacteria and ITS for fungi. Five disinfection protocols were evaluated, three of which were previously developed for sweet potato and included disinfection with 0.5, 1, and 2% sodium hypochlorite respectively, while two protocols are proposed in this work and included washing with povidone-iodine, disinfection with sodium hypochlorite 2%; one of these two new protocols also contains acetic acid and quaternary ammonium. For the evaluation of the viability of in vitro plants after disinfection, they were acclimatized in a greenhouse, reintroduced, and a molecular testing by PCR of 16S rRNA gene and ITS was carried out to verify the phytosanitary status of the material. The contaminating microorganisms found were filamentous fungi of the genera Fusarium, Sarocladium, Cladosporium and Aspergillus, yeasts of the genera Pseudozyma and Moesziomyces, and the actinobacterium Curtobacterium sp. The results indicated that washing with povidone-iodine and disinfection with 2% sodium hypochlorite, acetic acid and quaternary ammonium was the most efficient disinfection protocol, reducing the number of contaminated cultures by up to 10% and eradicating 70% of contaminants. The in vitro plants established in the greenhouse remained healthy and, after reintroduction, the molecular test for bacteria and fungi was negative. These results allowed the generation of an optimized protocol that can be incorporated into the in vitro micropropagation process to generate contamination-free sweet potato seeds.

A review on the potential health benefits of sweet potato: insights into its preclinical and clinical studies

SummarySweet potato (Ipomoea batatas (L.) Lam) has become a research focus in recent decades because of its nutritional and functional properties. Its leaves, stems and roots are a valuable source of bioactive carbohydrates, lipids, proteins, carotenoids, anthocyanins, phenolic acids and flavonoids. These bioactive metabolites possess many biological activities, such as antioxidant, antidiabetic, anticancer, hepatoprotective, antimicrobial, antiulcer and immunostimulant activities. Moreover, previous investigations proved that bioactivity varies qualitatively and quantitatively among sweet potato cultivars. So, the purpose of this review was to summarise the preclinical and clinical studies that have been conducted on different varieties of sweet potatoes, aiming to find the gap between them. This may consequently help in recommending additional clinical investigations on sweet potatoes maximising their potential as a functional food.

Quality Characteristics of Sweet Potato Jelly Prepared Using the Enzymatic Saccharification Method.

In this study, jelly was prepared using saccharified sweet potatoes without sugar, and its quality characteristics were compared according to the sweet potato cultivar. Three sweet potato varieties, namely Juwhangmi (orange color), Sinjami (purple color), and Daeyumi (yellow flesh color), were used. The total free sugar and glucose contents of the hydrolysate were found to increase during the enzyme treatment. However, no differences in the moisture, total soluble solids, or textural properties were found among the sweet potato cultivars. Sinjami had high total polyphenol and flavonoid contents of 446.14 mg GAE/100 g and 243.59 mg CE/100 g, respectively, and it had the highest antioxidant activity among the cultivars. Based on the sensory evaluation, an overall preference appeared in the order of Daeyumi, Sinjami, and Juwhangmi cultivars. This result shows that jelly can be manufactured by saccharifying sweet potatoes, and it was confirmed that the characteristics of raw sweet potatoes had a great influence on the quality characteristics of the jelly. Further, the characteristics of raw sweet potatoes had a remarkable influence on the quality characteristics of the jelly.

Influence of Blended Npsb Fertilizer Rates on Growth of Sweet Potato (<i>Ipomoea batatas</i> (L.) Lam) Varieties in Bako District, West Shewa Zone

Sweet potato (<i>Ipomoea batatas</i> (L) Lam) is one of the most important root crops. It is used as food and economically important crop in Ethiopia. However, its production and productivity is very low due to several factors: lack of information on the type and appropriate rate of fertilizers supplying major plant nutrients, which have been recognized to be deficient in Ethiopian soil and shortage of planting materials supplying system, Hence, a field experiment was conducted at Bako Agricultural Research Center in 2019/2020, to investigate the effect of blended NPSB fertilizer rates and sweet potato varieties on growth, components of sweet potato. Five different rates (0, 50, 100, 150 and 200 kg ha^-1) of blended NPSB fertilizer and two sweet potato varieties (Dimtu and Tola) were combined in a 5 X 2 factorial arrangement in a randomized complete block design with three replications. Data on growth components were collected and subjected to analyses of variance using SAS, version 9.3. The results of this experiment indicated that varieties and NPSB fertilizer rates highly significantly (p<0.01), and their interaction significantly (p<0.05) affected most of the growth parameters including: shoot fresh weight; shoot dry weight, vine length, days to bud sprout and days to physiological maturity. Tola at 100 kg ha^-1, 150 kg ha^-1 and 200kg ha^-1 NPSB fertilizer rates resulted in significantly (p<0.01) highest days to physiological maturity (136.69, 139.9 and 143.1) and the highest shoot fresh weight (653.3g, 668.3g and 690g), respectively. Dimtu at 0 kg ha^-1 fertilizer rates resulted in significantly (p<0.01) highest days to bud sprouting (14.0). In conclusion, the above findings indicated that the growth and productivity of sweet potato at the study area can be improved by the combined use of appropriate variety and application of optimum rate of blended NPSB fertilizer. However, as the results are limited to one season and location, further research needs to be conducted over more seasons and locations by considering also using the more than 200 kg ha^-1 of blended NPSB fertilizer rates and additional varieties to generate more reliable information.

Molecular genotyping of sweet potato (Ipomoea batatas L. Lam) accessions using microsatellites

The experiment was conducted to ascertain the level of genetic diversity in sweet potato accessions using microsatellites. Thirty sweet potato accessions obtained from the International Potato Center (CIP), Kumasi, Ghana, Mozambique, and local germplasm of the National Root Crops Research Institute (NRCRI), Umudike, Abia State, Nigeria, as well as sweet potato vines from local farmers' fields in Jos, Plateau State, and Bauchi State, Nigeria, were analyzed for genetic diversity using five microsatellite markers. The results showed that the polymorphic SSR loci revealed diverse relationship among the sweet potato cultivars, which was grouped into four major clusters by unweighted pair group method analysis (UPGMA) method. Cluster analysis showed a Jaccard co-efficient ranging from 0.0 to 3.0 indicating high genetic diversity. The primers detected a total of 18 alleles and the number of alleles per locus was 4 for IBR-19, IBR-286, IBR-297 and 3 for IBR-16 and IBR-242 with an average of 3.67 alleles per locus. The polymorphic information content (PIC) of the markers varied from 0.35 to 0.72 with an average of 0.497. Marker IBR-19 revealed the highest PIC of 0.72, while marker IBR-297 had the lowest PIC of 0.35. Observed heterozygosity ranged from 0.32 to 0.89 with a mean of 0.675 across the five SSR loci. The results from the Analysis of molecular variance (AMOVA) which was used to quantify the diversity level and genetic relationship among the thirty sweet potato accessions indicated that a high diversity was mostly distributed within the populations for sweet potato accessions (75.12%) and (15.67%) among the populations.