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Adventitious roots of 'Beauregard' and 'Georgia Jet' sweetpotato were observed and anatomically characterized over a period of 60 days of storage root development. The majority of 'Beauregard' and 'Georgia Jet' adventitious roots sampled at 5 to 7 days after transplanting (DAT) possessed anatomical features (five or more protoxylem elements) associated with storage root development. The majority of 'Beauregard' (86%) and 'Georgia Jet' (89%) storage roots sampled at 60 to 65 DAT were traced directly to adventitious roots extant at 5 to 7 DAT. The two varieties, however, differed in the timing in which regular and anomalous cambia were formed. Regular vascular cambium development, i.e., initiation and completion, was observed in both varieties at 19 to 21 DAT. Formation of complete regular vascular cambium was negligible for 'Beauregard' (4%) in comparison with 'Georgia Jet' (32%) at 26 to 28 DAT. However, anomalous cambia development adjacent to xylem elements was greater in 'Beauregard' (30%) in comparison with 'Georgia Jet' (13%). Nearly 40% to 50% of samples in both varieties showed extensive lignification in the stele region. At 32 to 35 DAT, 62% to 70% of the adventitious roots for both varieties had either been initiated (developed anomalous cambium) or were lignified. The remaining adventitious roots showed intermediate stages of vascular cambium development. The adventitious root count increased up to 19 to 21 DAT and then remained constant up to 32 to 35 DAT. These accumulated results suggest that the initial stages of adventitious root development are critical in determining storage root set in sweetpotato. [ABSTRACT FROM AUTHOR]

Abstract: The study established baseline data on the total phenolic content and antioxidant activities of five sweet potato (Ipomoea batatas) varieties grown in the Philippines including Dakol, Emelda, Haponita, PSBSP and Violet. Phenolic content ranged from 192.7 to 1159.0mg gallic acid equivalent (GAE) /100g dry sample. Antioxidant activities were highest for Dakol, with an EC50 value of 0.7±0.2mg/mL for DPPH radical scavenging activity, 2.5±0.5mg/mL for reducing power, and 2.4±0.3mg/mL for iron-chelating ability, on a dry basis. However, Haponita had the best inhibitory action on linoleic acid oxidation at 99.4±0.9%. Methanolic sweet potato extracts had higher radical scavenging activity, reducing power and oxidation inhibition than α-tocopherol and higher iron-chelating capacity than ethylenediamine tetraacetic acid (EDTA). Significant (∗P <0.05) negative correlation was observed between total phenolic content and the EC50 for DPPH radical scavenging activity (R =−0.826), reducing power (R =−0.876) and iron-chelating capacity (R =-0.800). [Copyright &y& Elsevier]

Abstract: To compare the β-carotene contents in different Chinese sweet potato (SP) varieties and to choose a variety of SP rich in β-carotene for the study of the effect of processing methods on β-carotene retention, β-carotene in thirteen varieties of sweet potato from China was measured by HPLC. The results showed that β-carotene contents were significantly correlated with SP flesh colours, with the orange-red fleshed SP varieties being higher in β-carotene. β-carotene contents in SP were affected by many factors, and this was demonstrated using the variety of Yanshu No.5, showing that the β-carotene contents in SP grown in different farming sites in the same area ranged from 53.2 to 84.3 mg kg−1 fresh weight. Moreover, β-carotene distributes unevenly in one SP root, with highest concentrations in the core. The β-carotene content was positively related to the root size. Five processing methods including boiling, steaming, microwave cooking, frying, and post steam-drying were simulated in the study to check their effects on the true retention of β-carotene in SP. Compared to boiling, steaming resulted in much more loss of β-carotene and microwave cooking resulted in the biggest loss of β-carotene among the five processing methods. Industrial relevance: Orange-fleshed sweet potato can be prepared for sale and consumption, using methods that protect the β-carotene content. This can aid in promoting sweet potato as a staple food as well as a snack food for supplying vitamin A for both rural and urban populations. Prepared orange-fleshed sweet potato can contribute to alleviating vitamin A deficiency in China as well as other low-income countries. [Copyright &y& Elsevier]

'Covington' is an orange-fleshed, smooth-skinned, rose-colored, table-stock sweetpotato [Ipomoea batatas (L.) Lam.] developed by North Carolina State University (NCSU). 'Covington', named after the late Henry M. Covington, an esteemed sweetpotato scientist at North Carolina State, was evaluated as NC98-608 in multiple state and regional yield trials during 2001 to 2006. 'Covington' produces yields equal to 'Beauregard', a dominant sweetpotato variety produced in the United States, but it is typically 5 to 10 days later in maturity. 'Covington' typically sizes its storage roots more evenly than 'Beauregard' resulting in fewer jumbo class roots and a higher percentage of number one roots. Total yields are similar for the two clones with the dry matter content of 'Covington' storage roots typically being 1 to 2 points higher than that of 'Beauregard'. 'Covington' is resistant to fusarium wilt [Fusarium oxysporum Schlect. f.sp. batatas (Wollenw.) Snyd. & Hans.], southern root-knot nematode [Meloidogyne incognita (Kofoid & White 1919) Chitwood 1949 race 3], and moderately resistant to streptomyces soil rot [Streptomyces ipomoeae (Person & W.J. Martin) Wakswan & Henricil. Symptoms of the russet crack strain of Sweet Potato Feathery Mottle Virus have not been observed in 'Covington'. The flavor of the baked storage roots of 'Covington' has been rated as very good by standardized and informal taste panels and typically scores as well or better in this regard when compared with 'Beauregard'. [ABSTRACT FROM AUTHOR]

Two sweet potato varieties suitable for different eating ways were selected to determine the ability to absorb trace elements and heavy metals. The results is very interesting: eight trace elements in variety Yanshu 25 were much high than those in variety Jishu 26, which proved that different varieties have different ability to absorb the trance elements. The heavy metals contents were highly similar to the contents of trace elements in two kinds of sweet Potato. When we choose sweet potato varieties with different eating methods, we can choose them according to the content of trace elements or heavy metals in them. [ABSTRACT FROM AUTHOR]

Previous work suggests that 'Beauregard' sweetpotato [Ipomoea batatas (L.) Lam.] has a much lower N requirement than other common cultivars. Over the past 10 years, 'Beauregard' has become the premier sweetpotato cultivar grown in Virginia; however, N fertilizer recommendations have not been reassessed to consider the potentially lower N requirement of 'Beauregard'. The objectives of this study were to evaluate the effects of N rate and application timing on root yield, quality, and N use efficiency for 'Beauregard' sweetpotato production in Virginia. A field study was conducted each year from 2000 to 2002 at the Eastern Shore Agricultural Research and Extension Center, Painter, Va. Nitrogen fertifizer was applied at rates of 28, 56, and 84 kg⋅ha-1 either before transplanting, 2 to 3 weeks after transplanting (WAT), or 4 to 5 WAT. A check treatment that received no N fertilizer was also included. Optimum N rates varied annually; under normal precipitation, root yield was greatest at the 28-kg⋅ha-1, rate, while 56 kg⋅ha-1 was required for maximum yield in wet conditions. Of note is that this range of rates is considerably lower than the current N recommendation for Virginia sweetpotato production (56 to 84 kg⋅ha-1). Delaying N application until 2 to 3 WAT further increased marketable root yield compared with applying N before transplanting or 4 to 5 WAT. Crude protein and N uptake increased with increasing N rate up to 84 kg⋅ha-1; however, N use efficiency was highest (67%) when 28 kg⋅ha-1 was applied 2 to 3 WAT. [ABSTRACT FROM AUTHOR]

Field experiments conducted from 1998 to 2000 are reported in which three legume green manure crops were studied for biomass production. The legume green manure crops and grass cover (control) were then turned into the soil as green manures and compared with inorganic fertilizer for production of two sweet potato varieties (Ipomea batatas (L.) Lam). Treatments comprised green manure legumes (Mucuna pruriens, Centrosema pubescens, Pueraria phaseoloides), natural grass cover (control) and inorganic fertilizer NPK. Sweet potato varieties were TIS 87/0087 and TIS 8164. All possible combinations of sweet potato varieties and the manure treatments were laid out in a randomized complete block design with three replications. Mucuna pruriens produced significantly higher biomass than Centrosema pubescens and Pueraria phaseoloides at 2 months after planting (MAP) in May-established green manure plots but not in August plantings. At 10 MAP in August establishment, however, Centrosema pubescens and Pueraria phaseoloides gave higher dry matter than Mucuna pruriens. Biomass production increased up to 3 MAP, with the dry matter obtained with Mucuna and natural grass cover being over 4 t ha-1 at 3 MAP in August establishment. Soil nitrogen was significantly higher with Mucuna than with other legumes and natural grass fallows. Sweet potato tuber yields obtained from Mucuna improved fallow were similar to those obtained with NPK fertilizer treatment, which was better than the yield with Pueraria and natural grass fallow. Sweet potato variety TIS 8164 produced significantly higher tuber yield than TIS 87/0087 in 1999 but not in 2000. Sweet potato tuber yields were higher with the two-year fallow than with one-year fallow by 176%. [ABSTRACT FROM AUTHOR]

The article examines the involvement of anthocyanins and other phenolic compounds in 1,1 Diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity of purple-fleshed sweet potato cultivars. Results of high-performance liquid chromatography analysis showed the high anthocyanin content of Ayamurasaki, while Miyanou-36, Bise and Tanegashimurasaki contained cyanidin aglycon. The researchers also measured the color value of sweet potato powder.

New-found interest in sweetpotato production in the Mid-Atlantic and Northeastern U.S. has been steadily increasing in the last several years. Sweetpotatoes are usually grown for fresh market use and novel marketing strategies and new consumer niches are providing farmers options of growing new sweetpotato varieties with exciting colors and flavor profiles that are adapted to the Mid-Atlantic and Northeastern U.S. Petite sweetpotatoes have gained market attention because they are easier to handle and faster to cook compared to U.S. No. 1 storage roots. The goal of this research was to determine the performance and adaptableness of eight commercial sweetpotato varieties and two unreleased accessions for U.S. No.1 and Petite sweetpotato production under black plastic mulch tailored for the mild temperate growing conditions of the Mid-Atlantic and Northeastern U.S. Two in-row spacings (15 cm and 30 cm) and two harvest dates (90 and 120 days after planting, DAP) were evaluated during the 2018 and 2019 growing seasons. Our results showed that the ideal harvest time is at least 120 DAP compared to an early harvest at 90 DAP as there was a 2-fold difference in marketable yield at both 15 and 30 cm in-row spacing with marketable yield between 20 and 54 t ha−1. 'Averre' and 'Beauregard' produced the highest U.S. No. 1 and Petite yields under both in-row spacing treatments harvested at 120 DAP for both years evaluated, though the general effect of in-row spacing and DAP interaction (separate years) on yield performance was cultivar specific. We also found that growing degree days is a better predictor for harvest than days after planting, with an accumulation of at least ~700 GDD (base temperature 15.5 °C) or ~1300 GDD (base temperature 10 °C) for both U.S. No. 1 and Petite roots. Additional studies are required to identify the stability of cultivars tested and treatments imposed with environmental interactions in this region. In addition, there is an urgency for updated sweetpotato management practices exclusively designed for sweetpotato varieties for the Mid-Atlantic and Northeastern U.S. [ABSTRACT FROM AUTHOR]

The name Bulcha was given to a yam (Dioscereaalata) variety with the pedigree name of BRC-8s, and the name Lalo was given to a yam (Dioscorearotundata) variety with the pedigree name of BRC-7l. The two varieties were evaluated under a regional variety trial for two years (2006 and 2007) at Bako, Gute and Tsige districts and released by Bako Agricultural Research Center in 2012. These two yam varieties showed superior performance particularly in terms of productivity and tolerance to disease across the years and locations. The two newly released varieties out-yielded the other tested yam genotypes on both research plots and farmers' fields. Bulcha produced tuber yields 66.45 and 31.4 t/ha and Lalo produced tuber yields of 46.0 tons and 22.7 t/ha on research plots and farmers' field, respectively. [ABSTRACT FROM AUTHOR]

The article presents information on Burgundy sweetpotato, which was developed by the Louisiana Agricultural Experiment Station. It provides a background on the origin of the cultivar, whose female lineage is NC96-61 from the North Carolina State University Sweetpotato Breeding Program but its male parent is unknown. Information is also presented on the cultivar's features, disease reactions, insect performance, and availability.

The article focuses on the orange-fleshed sweetpotato (OFSP) cultivars called SPK004 and Ejumula approved for release by the Ugandan Plant Variety Release Committee in April 2004. A set of 25 OFSP clones were used for the breeding of the landrace cultivars. The varieties have pale purple limb with purple throat flowers and have high root dry matter content. The OFSP cultivars are susceptible to sweetpotato weevils.

Sweet potato (Ipomoea batatas) is one of the ten most important staple crops and provides a livelihood for many people around the globe. To adapt to ever-changing circumstances farmers and breeders need to have access to a broad diversity of germplasm. This study focuses on the development of a cryopreservation protocol that allows the long term storage of different sweet potato cultivars. For this, a droplet vitrification protocol was optimized, comparing several parameters; preculture method (0.3 M sucrose vs no preculture); meristem position (axillary vs apical); plant age (3 to 9 weeks); regeneration medium (MS + 2.22 µM BA, Hirai and MS); and length of loading solution treatment (20 to 360 min). Two months after cryopreservation, the regeneration rates of the meristems were compared, which resulted in significant differences for the preculture method, meristem position and loading solution. With these new insights an optimized droplet vitrification protocol was developed with the following parameters: use of 3–9 week old axillary meristems, no preculture phase, 20 min LS treatment, 30 min PVS2 treatment, exposure to liquid nitrogen by droplet vitrification, warming treatment in RS for 15 min, 1 day 0.3 M sucrose recuperation culture, 1 month MS + 2.22 µM BA followed by 1 month of MS cultures. This protocol was subsequently tested on 10 representative accessions resulting in a post cryopreservation regeneration rate of more than 40% for 70% of the tested cultivars, showing that this protocol could be implemented for a large portion of existing sweet potato collections. [ABSTRACT FROM AUTHOR]

The unidirectional thermoplastic commingled yam composites have been fabricated from three different varieties of yams in a hot press and then studied for the bending properties on DCS-500 tester using three-point loading system. It is observed that the bending properties of composites, especially the transverse bending properties, are affected by the mixing degree of reinforcing fibre/matrix fibres and bulkiness of reinforcing fibres bundle. [ABSTRACT FROM AUTHOR]

The activities and gene expression of antioxidative enzymes and the ROS content were analyzed in two typical storage-tolerant cultivars (Xushu 32 and Shangshu 19) and another two storage-sensitive cultivars (Yanshu 25 and Sushu 16) to explore the association between the storage capacity of sweetpotato (Ipomoea batatas (L.) Lam) and ROS scavenging capability. The storage roots of the storage-tolerant cultivars maintained higher activities and expression levels of antioxidative enzymes, including ascorbate peroxidase (APX), peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD); lower activity and expression of lipoxygenase (LOX); and lower accumulation of ROS metabolites compared with the storage-sensitive cultivars. The antioxidative capability and ROS parameters of leaves were positively correlated with those of storage roots. Our results provide valuable insight for evaluating the storability of sweetpotato cultivars by analyzing the capabilities of the antioxidative system and the contents of ROS metabolites. [ABSTRACT FROM AUTHOR]

The article presents a study regarding the dispersal of sweet potatoes originating from South America to Polynesia. It discusses the research by C. Roullier and colleagues regarding the history of sweet potatoes to Oceania by using genetic analyses confirms some aspects in the "tripartite hypothesis". It also mentions several varieties of sweet potato which includes the "kumara" lineage, "camote" introduced by Spanish galleons, and the "batata" believed to be brought by Portuguese traders.

The article offers a description of the "Orleans" sweetpotato cultivar developed by the Louisiana Agricultural Experiment Station. The cultivar is similar to "Beauregard" with superior storage root shape and disease resistance. Information is provided on the origin, disease reactions, insect resistance, quality attributes and availability.

The article offers information on Murasaki-29 sweetpotato, which was developed by the Louisiana Agricultural Experiment Station to provide a specialty-type white flesh, dark purple skin cultivar with southern root-knot nematode and soil rot resistance. It notes that the sweetpotato produces excellent numbers of uniform plants early in the production season. It cites that the sweetpotato has green-stemmed vines. It states that Murasaki-29 has not shown any unusual propensity to insect damage in several on-farm trials.

Sweet potato starches were characterized to understand the changes upon modification by acid and heat-moisture treatment (HMT) in the rheological, differential scanning calorimetry (DSC), and textural characteristics of starch isolated from the sweetpotato variety PSP-21 and to compare these findings with those of commercially available arrowroot starch. The native sweetpotato starch had a Type A pasting profile characterized by a high peak viscosity (PV) (741.5 rapid viscoanalyzer unit [rvu]), with a high breakdown (378.8 rvu) and low cold paste viscosity (CPV) (417.6 rvu). After HMT, there was a marked decrease in the PV (639.1), a very slight breakdown (113.5 rvu) and an increase in CPV (759.5 rvu), more like a Type C pasting profile. However, acid modification did not notably change the pasting profile of native sweetpotato starch. The DSC characteristics were also affected significantly after modifications. The gelatinization temperature parameter to onset (To) decreased significantly after HMT and acid modification. The gelatinization enthalpy decreased during HMT from 15.98 to 14.42 J/g. The gel strength of acid-modified starch was the highest compared with that of HMT and native sweetpotato and arrowroot starches. [ABSTRACT FROM AUTHOR]