Sweet Potato Clones Research Articles

Genotype × Environment Interactions for East African Orange‐Fleshed Sweetpotato Clones Evaluated across Varying Ecogeographic Conditions in Uganda

African dry and starchy (DS) orange‐fleshed sweetpotato [Ipomoea batatas (L.) Lam] (OFSP) cultivars, distinct from American moist or medium dry and sweet OFSP, have potential to fight vitamin A deficiency (VAD) in the world. This study assessed the genotype × environment (G × E) interactions in multienvironment trials (METs), the genetic correlations for total root yield (TYLD), biomass (BIOM), harvest index (HI), root dry matter (RDM), root starch (RST), root sucrose (RSU), root β‐carotene, (RBC), root Fe (RFE), root Zn (RZN), root Ca (RCA), and root Mg (RMG) and the potential contributions of the cultivars to fight VAD and mineral deficiencies. Nine DS OFSP cultivars, (Ejumula, Zambezi, Carrot_C, Kakamega, KMI61, Abuket_1, SPK004/6/6, SPK004/6 and Naspot_5/50) and a medium dry and sweet OFSP cultivar (Resisto) were tested in METs in Uganda. The components were smaller than components for HI, RDM, RST, RSU, and RBC, making it possible to ably select for the traits in the early stages. The components were larger than components for TYLD and mineral traits. Thus, like yield, breeding for mineral traits in sweetpotato is complex, requiring prior data on the causes of the G × E interactions. Medium to high positive correlations among mineral traits favor parallel selection, and it merits further study to efficiently improve the mineral trait complex by an index. Clearly, a 50‐ to 100‐g ration of all the cultivars, except Naspot_5/50, can provide 100% recommended dietary allowance of vitamin A for a 5‐ to 8‐yr‐old child.

English

Twenty accessions of sweet potato (Ipomoea batatas L. Lam) cultivated under rain-fed conditions were evaluated based on their agromorphological traits to assess diversity in yield, morphology and other key agronomic characteristics of the accessions under study. The accessions consisted of 13 local and 7 exotic breeding lines grown in the research farm of the Biotechnology and Nuclear Agriculture Research Institute during the rainy and dry seasons of 2011. The Randomised Complete Block Design (RCBD) was used with four replicates. Results indicate high genetic variability among the 20 accessions based on the agromorphological and yield characteristics. The exotic accession (US 020) recorded the highest total root yield and harvest index of 56.32 t/ha and 57.11%, respectively, indicating its superiority over the local accessions. Two accessions (ER 001 and HMA 2) were found to be possible duplicates. This study provides valuable information that can be utilised in a breeding programme to ameliorate local clones of sweet potato in Ghana. Key words: Sweet potato, accessions, agromorphological characteristics, harvest index, total root yield, percent dry matter, Ghana.

Selection of promising sweet potato clones using projective mapping

Increasing demand for sweet potato in regions with temperate climates has triggered interest in the development of new cultivars. Breeding of this crop should consider sensory characteristics in order to meet consumers' expectations. This requires the application of simple and cost-effective methodologies that allow quality evaluation from a sensory perspective. With the objective of identifying the key sensory characteristics of different sweet potato genotypes, two commercial cultivars and seven clones were evaluated during three consecutive years using projective mapping by an untrained consumer panel. This methodology allowed the discrimination of the genotypes, identifying similarities and differences among groups based on sensory terms selected by the assessors. Genotypes were differentiated in terms of texture and flavor characteristics (firmness, moisture, smoothness, creaminess, flavor intensity, sweetness and bitterness). Materials for future crossings were identified. The evaluation of the sensory characteristics of sweet potato clones and cultivars using projective mapping is a quick, cost-effective and reliable tool for the selection of new advanced sweet potato clones with superior sensory characteristics compared to the reference cultivars INIA Arapey and Cuarí. © 2016 Society of Chemical Industry.

Cooking Treatment Effects on Sugar Profile and Sweetness of Eleven-Released Sweet Potato Varieties

Cooking can significantly alter sugar content of sweet potato roots. Sweet potato roots were processed using three different cooking treatments, with the aim of investigating the effects of these methods on sugar profile and sweetness levels. Significant contribution of the cooking treatment and genotype, and their interaction on levels of the sugars were also determined. Moreover, sugar values were converted to relative sweetness per sucrose equivalent. The results revealed that cooking treatment produced the highest effect on sugar except fructose. Variability due to the interactions was significant and ranged from 2.60% to 11.74%. Whilst sucrose was the predominant in the raw form, maltose increased dramatically during cooking. Sweetness level increased substantially upon cooking and was highly dependent on initial sugar content, amylase activity and cooking treatment. Thus, evaluation of sweetness levels in sweet potato clones should not only be on the uncooked samples but should take into account the cooking methods employed.

PRODUKTIVITAS LAHAN, KOMPETISI, DAN TOLERANSI DARITIGA KLON UBIJALAR PADA SISTEM TUMPANG SARI DENGAN JAGUNG

ABSTRACT Paulus, J.M. 2005. Land Productivity, Competition, and Tolerance of Three Sweet Potato Clones Planted as Intercroping with Maize. Eugenia 11 (1): 1-7. A field experiment was conducted in Cikeumeuh Experimental Garden of Food Crop Biotechnology Research Station (BAUTBIO) Bogor to study Land Equivalent Ratio (LER), Competition Ratio (CR), and Stress Tolerance (TOL) of sweet potato and maize. The highest tuber yiled of sweet potato was 16,83 ton ha-[1] gained by CIP-2 at 100 cm planting distance of maize and the highest maize yiled was 4,50 ton ha-1 Cangkuang in intercropping with Cangkung clone. The LER, CR, and TOL, CIP-2 and SQ were suitable for intercrops at all planting distance but Cangkuang was not suitable for intercrops with maize. Keywords: Ipomoea batatas, clon, intercroping [1] Jurusan Budidaya Pertanian, Fakultas Pertanian UNSRAT Manado, 95115

The Carbohydrate Yield of Sweetpotato (Ipomoea batatas) Grown from Slips and Root Pieces in North Carolina

Sweetpotato (Ipomoea batatas) is one of the world’s most important and widely grown starch crops. It is usually produced for direct human consumption but can be readily converted to simple sugars that then have industrial end uses. The objective of this study was to compare the carbohydrate yield of the conventional sweetpotato cultivar, Beauregard, with new clones selected specifically for higher carbohydrate production. Ten sweetpotato clones were grown from both slips and root pieces at five locations, over 2 years, in North Carolina. A sweetpotato clone selected for high carbohydrate production, and planted as slips, yielded on average 4150 kg·ha−1 of carbohydrates, 10% to 15% higher than Beauregard. The chemical composition of roots was unaffected by planting method, but slips usually outyielded the same clone grown from root pieces. Carbohydrate yield was significantly impacted by genotype × environment effects in both slips and root pieces. We conclude that further work will be needed to develop sweetpotato clones with both high carbohydrate content and high yield potential, and that are also adapted to planting from root pieces. Any breeding and development work will need to take into account genotype × environment effects.

Screening of Tanzanian sweet potato germplasm for yield and related traits and resistance to sweet potato virus disease

Sweet potato (Ipomoea batatas [L.] Lam) is a versatile crop globally serving as food, feed and raw material for industries. Designed selection for higher yields and related traits is crucial to identify complementary sweet potato clones for breeding. The objective of this study was to determine phenotypic variation among diverse sweet potato collections with regard to yield, dry matter content (DMC) and sweet potato virus disease (SPVD) resistance and to identify suitable clones for breeding. A total of 144 sweet potato genotypes were evaluated at 2 sites in Tanzania using a 12 × 12 simple lattice design. Data collected included 10 quantitative and 17 qualitative agro-morphological traits and virus reaction. Results indicated differences among genotypes for most traits studied. The mean DMC was 36% with clones Zapallo and Ukerewe exhibiting the lowest and highest values of 29% and 45%, respectively. The mean storage root yield of clones was 5.1 t/ha with genotype Jewel expressing the highest yield of 11.3 t/ha. Genotypes Resisto and Mataya were early flowering at 40 and 50 days, respectively, while Ex-Mwanza and Kandoro did not flower at all. Fifty-eight per cent of the genotypes showed resistant reaction to SPVD, while 31% and 11% were moderately susceptible and susceptible to the disease, respectively. A positive correlation was observed for the number of roots and fresh root yield. Seven clones including Simama, Ukerewe, Mataya, Resisto, 03–03, Ex-Msimbi-1 and Gairo were selected for high storage root yield and related traits or SPVD resistance. The selected genotypes are recommended as potential parents for sweet potato breeding.

Características produtivas de clones de batata-doce cultivados em três períodos de cultivo em São Cristóvão-SE

O objetivo do presente trabalho foi avaliar o desempenho de clones de batata-doce cultivados em diferentes períodos. O delineamento experimental foi de blocos casualizados, em esquema de parcelas subdivididas, com três repetições. Foram testados nas parcelas três períodos de cultivo (3, 5 e 7 meses), e nas subparcelas, cinco clones de batata-doce (acessos IBP-007, IBP-038, IBP-075, IBP-079 e IBP-149), e a cultivar comercial Brazlândia Rosada. As variáveis analisadas foram sobrevivência, danos causados por insetos de solos (notas de 1 a 5 onde 1= sem danos e 5= muitos danos, sem valor comercial), massa fresca e seca de parte aérea, produtividade total de raízes. Os maiores danos causados por insetos de solo observou-se no clone IBP-007 (4,29), e menores danos nos clones IPB-038 (2,84), IPB-075 (3,01) e IPB-149 (2,88), que apresentaram resistência no cultivo durante sete meses. O clone IPB-007 apresentou elevados valores de massa fresca (14,07 t/ha) e seca (2,81 t/ha) de parte aérea, em todos periodos de cultivo, apresentando também, alta produtividade de raizes (33,16 t/ha). Recomenda-se cultivar a batata doce durante um período de cinco meses.

Resistance of sweet potato clones to meloidogyne incognita races 1 and 3

The objective of this study was to evaluate sweet potato clones for resistance to root-knot nematode, Meloidogyne incognita races 1 and 3. For each nematode physiological race, a greenhouse experiment was set up in a randomized block experimental design with three replications and six plants per plot. Fifty-eight sweet potato clones from the UFVJM germplasm bank were evaluated, plus five commercial cultivars (Brazlândia Rosada, Brazlândia Branca, Palmas, Princesa and Coquinho), plus the cv. Santa Clara tomato (susceptible to Meloidogyne spp.). Stems were planted in 72-cell expanded polystyrene trays, filled with commercial substrate and inoculated with the pathogen thirty days after planting. Forty-five days after inoculation, the eggs were extracted, counted, and later evaluated. Resistance level classification was performed based on reproduction factor (RF) and reproduction index (RI). Among the 63 analyzed clones, a percentage of 78% were classified as resistant to M. incognita race 1.79% to race 3 and 67% showed multiple resistance to both M. incognita races.

Identifikasi Sifat Fisik, Kimia, dan Sensoris Klon-klon Harapan Ubijalar Kaya Antosianin

<p>Breeding for sweet potato varieties rich in anthocyanins is essential to promote the use of sweet potato as functional food as well as to support food diversification program. This study was performed to identify physical, chemical, and sensorial characteristics of 10 promising clones of purple-fleshed sweet potato and two varieties (Ayamurasaki and Antin 1) as checks, at the Food Chemistry and Processing Laboratory of ILETRI, Malang from November until December 2012. The trial was arranged in a completely randomized design with three replicates. Observations included physical and chemical characteristics of the fresh roots and sensory attributes of the steamed roots using hedonic test of 20 panelists. The flesh colour varied from white/yellow purplish, purple up to dark purple. The lightness colour (L*) of root flesh was negatively correlated with total anthocyanins (R2 = 0.81), which varied from 1.86 mg (MSU 06044-05) up to 123.92 mg equivalent to cyanidin 3-glycoside/100 g fw (MSU 06046-48). Three clones, namely MSU 06046-48, MSU 06028-71, and MIS 0601-179 had higher total anthocyanins than that of Ayamurasaki (70.41mg/100 g fw) as a check. Moisture, ash, crude fiber, reducing sugar, amylose, and starch contents also varied among clones, ranged from 67.7 to 75.8%; 2.8 to 3.9% dw; 2.5 to 4.8%; 0.9 to 4.4% dw; 20.0 to 27.4% dw and 50.3 to 66.6% dw, respectively. MIS 0601-179 clone had the highest dry matter and starch contents (40.05% dw and 66.64% dw) which were suitable for flour ingredient. The steamed roots of MSU 06044-05 (yellow purplish) gave the highest scores of panelist preferences on colour, texture and taste attributes, followed by MIS 0601-179, Ayamurasaki, and MSU 06028-71 (purple). The bitter taste of MSU 06046-48 steamed roots associated with the highest anthocyanins content was slightly disliked, suggesting that this clone needs an alternative preparation method other than steaming.</p>

The genome of cultivated sweet potato contains Agrobacterium T-DNAs with expressed genes: An example of a naturally transgenic food crop.

Agrobacterium rhizogenes and Agrobacterium tumefaciens are plant pathogenic bacteria capable of transferring DNA fragments [transfer DNA (T-DNA)] bearing functional genes into the host plant genome. This naturally occurring mechanism has been adapted by plant biotechnologists to develop genetically modified crops that today are grown on more than 10% of the world's arable land, although their use can result in considerable controversy. While assembling small interfering RNAs, or siRNAs, of sweet potato plants for metagenomic analysis, sequences homologous to T-DNA sequences from Agrobacterium spp. were discovered. Simple and quantitative PCR, Southern blotting, genome walking, and bacterial artificial chromosome library screening and sequencing unambiguously demonstrated that two different T-DNA regions (IbT-DNA1 and IbT-DNA2) are present in the cultivated sweet potato (Ipomoea batatas [L.] Lam.) genome and that these foreign genes are expressed at detectable levels in different tissues of the sweet potato plant. IbT-DNA1 was found to contain four open reading frames (ORFs) homologous to the tryptophan-2-monooxygenase (iaaM), indole-3-acetamide hydrolase (iaaH), C-protein (C-prot), and agrocinopine synthase (Acs) genes of Agrobacterium spp. IbT-DNA1 was detected in all 291 cultigens examined, but not in close wild relatives. IbT-DNA2 contained at least five ORFs with significant homology to the ORF14, ORF17n, rooting locus (Rol)B/RolC, ORF13, and ORF18/ORF17n genes of A. rhizogenes. IbT-DNA2 was detected in 45 of 217 genotypes that included both cultivated and wild species. Our finding, that sweet potato is naturally transgenic while being a widely and traditionally consumed food crop, could affect the current consumer distrust of the safety of transgenic food crops.

Avaliação agronômica de clones de batata doce com potencial para produção de etanol

The sweet potato is a culture that fits the most diverse Brazilian environmental conditions and has great potential for the production of ethanol from the use of their roots. And can be used both as food and feed.The objective was to evaluate sweet potato clones with potential for producing ethanol, starch yield and production potential of dry branches and roots.The experimental design was randomized blocks, using 60 treatments, 50 clones and 10 witnesses with three replications.Genotypes were belonging to LASPER (Research Laboratory and Production Renewable Energy). We evaluated the productivity of roots and branches, starch content and dry matter of roots and branches and resistance to soil insects.The clones 048-02, 112-07, 022-19, 048-14, 114-18, agronomically have potential for production of fuel ethanol.The clones 002-580 and 106-62 can be used in animal feed using their branches.There was no significant difference between treatments evaluated for the starch content.Witnesses had higher dry matter of roots, cultivars highlighting: Carolina Victory, Duda, and Marcela. The Barbara witnesses, Duda, Carolina Victoria and Beatrice are tolerant incidence of damage caused by soil insects.

Screening sweetpotato genotypes for tolerance to drought stress

Soil moisture stress due to drought results in low storage root yield of sweetpotato. Eighty-four sweetpotato clones were evaluated at Kenya Agricultural Research Institute (KARI), Kiboko and Thika between May 2011 and September 2012 for drought tolerance. A split plot design with drought stress and no drought stress conditions as whole plots, and clones as subplots, arranged in a 14×6 alpha lattice design with two replicates repeated in two seasons was used. Approximately 30cm long vine cuttings of each clone were planted 10cm deep on 25cm high beds, in single rows of 6 hills spaced at 30×90cm. The field study was also validated in screenhouse box experiments at KARI-Muguga. Data on growth and yield characteristics were recorded and analysed using SAS 9.2 edition. Across sites, data indicated that genotype, environment, and their interaction significantly differed for fresh storage root weight (FSR) (kgplant−1), total fresh biomass weight (FB) (kgplant−1), marketable fresh storage root weight (MFSR) (kgplant−1), harvest index (HI) and chlorophyll content (CC) (8.47%) at (P≤0.05). Comparing data from both environments, drought stress caused a reduction of FSR (59.3%), FB (72.1%), MFSR (75.5%), NSR (25.6%), but seemed to increase percent root dry matter (%RDM) (−0.29%), and HI (−26.6%). Clones 194555.7, Unawazambane06-01, 189150.1, Tanzania, Chingova, W119, 441725, and Xiadla-xa-kau, had ≥75 days to permanent wilting point (DPWP), drought stress index (DSI) <1 and high FSR yield under drought stress and no drought stress conditions. These clones may be used in a drought tolerance breeding programme. Clones that had low DSI values, also had low FSR yield difference under drought and no drought environment, indicating they were drought tolerant, but had less DPWP. However, high yielding clones under no drought, also had relatively high yield difference between drought and no drought environments, and high DSI values, which implied less drought tolerance. Thus, DPWP demonstrates high discriminative power to identify clones with both drought tolerance and improved yielding ability, especially in root crops such as sweetpotato, which occasionally produce pencil roots instead of edible storage roots even under adequate moisture conditions.

Sweetpotato Grown from Root Pieces Displays a Significant Genotype × Environment Interaction and Yield Instability

Various workers have attempted to develop a root piece planting system for sweetpotato, similar to the system used commercially for potato, but attempts to select and breed sweetpotato clones adapted to root piece planting have met with mixed success. It has been hypothesized this is the result of significant genotype × environment effects, which are complicating phenotype screening. The aim of this work was to investigate genotype × environment interactions and yield stability of sweetpotato grown from cut root pieces. Ten sweetpotato clones were grown from cut root pieces in three locations over three seasons at sites in North Carolina and Mississippi. The study found sweetpotato clones grown from root pieces were influenced by both genetic and environmental factors and that the interaction was often complicated and dependent on the trait being measured. A significant genotype × environment interaction and yield instability were found to be present. Further work will be required to understand the nature of the genotype × environment effects; however, the results suggest programs aiming to develop sweetpotato clones adapted to root piece planting will need to use appropriate multienvironment screening so as to account for genotype × environment effects.

Development of NIRS models to predict composition of enzymatically processed sweetpotato

This study was conducted to develop calibration models to predict the major constituents (moisture, protein, fiber, alcohol insoluble solids (AIS), and starch) of enzymatically processed sweetpotatoes using a non-destructive near-infrared spectroscopy (NIRS) technique. Prediction of these constituents is of interest since starch content can be used to estimate crop potential and efficiency of processing enzymes used to convert starch into valuable products needed for industrial applications. Wet chemistry procedures are expensive, laborious, and time consuming; however, NIRS is a reliable and fast tool that can be used to quantify components and identify composition changes occurring during sweetpotato processing. Freeze-dried samples of sweetpotato roots (clones: NC-413, DM02-180, and Covington) were scanned over the near infrared wavelengths at different stages of processing (unprocessed material, wet samples after liquefaction, and wet samples after saccharification) and chemically analyzed. Calibration models were established by Multiple Linear Regression (MLR) analysis and developed to predict moisture, AIS, protein, fiber, and starch content. Spectral range and the number of MLR factors were examined in a stepwise manner that yielded the lowest standard error of calibration (SEC) and highest correlation coefficient of determination (R2). Calibration models based on all sweetpotato clones adequately predicted moisture, AIS, and starch compounds in unprocessed and processed treatments. Protein was successfully predicted with 99% confidence for unprocessed material and an approximate quantitative prediction in processed treatments (R2=0.69). Fiber was predicted with 85% confidence for Covington sweetpotato and with 65% for both NC-413 and DM02-180 sweetpotato clones. Starch was successfully predicted with 91% and 97% confidence for unprocessed and processed treatments, respectively. Our results indicated that NIRS technique is a tool able to rapidly predict with reasonable accuracy the composition of different constituents present in sweetpotato samples before and during its processing to value-added products.

Influence of harvest time and cultivation sites on the productivity and quality of sweet potato

Sweet potato is one of the most cultivated tuberous roots in tropical and subtropical regions permitting several ways of use. Despite its potential use, sweet potato has been little studied. We evaluated the performance of sweet potato roots, forage productivity and its silage at different harvesting times and cultivation environments and we identified the most superior clones under different soil and climatic conditions. Six sweet potato clones (BD-38, BD-45, BD-25, BD-31TO, BD-15 and BD-08) belonging to germplasm bank of UFVJM in addition to two standard cultivars Brazlândia Rosada and Princesa were grown in two cultivation sites (JK campus and Forquilha farm). The trial was conducted in split plots in randomized block design with three harvest times (120, 150 and 180 days after planting). The mean root weight obtained from Forquilha farm was on average 30.2% higher than those obtained from JK campus. Regardless the site, harvesting at 150 days after planting was the optimal time for maximizing root production. The irregularity of root shape increased when the harvesting date was postpone, probably due to greater exposure to environmental factors. Crude protein, fibers, ash and starch, were not affected by local x cultivar interaction except for starch content that depended on the clone and site interaction.

Path analysis in characteristics of sweet potato clones aiming ethanol yield

El desarrollo de nuevos productos es un imperativo para las empresas, por lo que aumenta la necesidad de estudios que tratan de encontrar nuevas formas de utilizar las materias primas dentro de la practica de mercado de los biocombustibles. La patata dulce es un vegetal de gran potencial energetico, y se puede utilizar directamente para la produccion de etanol. Se realizo un experimento en condiciones de campo en la Estacion Experimental de la Universidad Federal de Tocantins en la Ciudad de Palmas, con el objetivo de estimar las correlaciones genotipicas, fenotipicas, ambientales y efectos directos e indirectos de coeficientes de trilla en el rendimiento de etanol. El diseno experimental fue completamente al azar representado por 100 tratamientos (clones de patata dulce) en tres repeticiones. Las caracteristicas estudiadas fueron el rendimiento de materia seca, productividad, almidon y la produccion de etanol. Las correlaciones genotipicas mostraron el mismo signo, y en la mayoria de los casos, valores correspondientes a las correlaciones fenotipicas, lo que indica que la expresion fenotipica se reduce frente a las influencias ambientales. La seleccion de plantas con altos niveles de materia seca posibilitaria el mejoramiento indirecto para los materiales con mayor produccion de etanol.

Behavior of roots of sweet potato clones

O objetivo deste trabalho foi avaliar o desempenho agronômico de vinte acessos de batata-doce originados do programa de melhoramento, juntamente com cinco cultivares comerciais (Brazlândia Branca, Brazlândia Rosada, Brazlândia Roxa, Canuanã e Palmas), cultivadas no período de fevereiro a agosto de 2006, em campo aberto, no município de Ijaci, Minas Gerais. Utilizou-se o delineamento em blocos casualizados, com três repetições. Cada parcela foi composta por dezesseis plantas. As raízes foram avaliadas quanto à produtividade total, peso médio, produtividade comercial, peso médio de raízes comerciáveis, formato e resistência aos insetos de solo. Dentre os vinte acessos avaliados, cinco foram promissores quanto ao formato de raízes, e quinze apresentaram resistência aos insetos de solo. Nove acessos e a cultivar Canuanã apresentaram produtividade comercial abaixo da média nacional. Quatro acessos produziram raízes de peso médio da melhor classificação comercial. A cultivar Palmas e o acesso UFT-08 foram os mais promissores quanto à produtividade de raízes comerciáveis, e apresentaram formato aceitável e moderada resistência aos insetos de solo. O clone UFT-22 também se mostrou promissor, com produtividade comparável às cultivares comerciais, formato de raiz regular e moderada resistência aos insetos. Abstract An experiment was carried out to evaluate the agronomic performance of twenty sweet potato accessions from a plant breeding program, together with five commercial cultivars (Brazlândia Branca, Brazlândia Rosada, Brazlândia Roxa, Canuanã and Palmas), cultivated out from February to August of 2006, in open field, at the municipality of Ijaci, Minas Gerais, Brazil. The assay was realized in randomized blocks design, with three replicates. Each plot was composed by sixteen plants. Roots were evaluated as for the total yield, root weight, marketable root yield, marketable root weight, form and resistance to soil insects. Among the accessions evaluated, five presented acceptable root form, and fifteen presented resistance to soil insects. Nine accessions and the cultivar Canuanã presented root yields lower than the national mean. Four accessions presented roots with average weight of the best commercial classification. The cultivar Palmas and the accession UFT-08 were the most promising among all clones, with superior marketable root yield, and presented acceptable commercial form and moderate resistance to soil insects. Accession UFT-22 was promising too, with marketable root yield similar to commercial cultivars, regular root form and moderate resistance to soil insects.

Role of anthocyanin-enriched purple-fleshed sweet potato p40 in colorectal cancer prevention.

Anthocyanins, the natural pigments in plant foods, have been associated with cancer prevention. However, the content of anthocyanins in staple foods is typically low and the mechanisms by which they exert anticancer activity is not yet fully defined. We selected an anthocyanin-enriched purple-fleshed sweet potato clone, P40, and investigated its potential anticancer effect in both in vitro cell culture and in vivo animal model. In addition to a high level of total phenolics and antioxidant capacity, P40 possesses a high content of anthocyanins at 7.5 mg/g dry matter. Treatment of human colonic SW480 cancer cells with P40 anthocyanin extracts at 0-40 μM of peonidin-3-glucoside equivalent resulted in a dose-dependent decrease in cell number due to cytostatic arrest of cell cycle at G1 phase but not cytotoxicity. Furthermore, dietary P40 at 10-30% significantly suppressed azoxymethane-induced formation of aberrant crypt foci in the colons of CF-1 mice in conjunction with, at least in part, a lesser proliferative PCNA and a greater apoptotic caspase-3 expression in the colon mucosal epithelial cells. These observations, coupled with both in vitro and in vivo studies reported here, suggest anthocyanin-enriched sweet potato P40 may protect against colorectal cancer by inducing cell-cycle arrest, antiproliferative, and apoptotic mechanisms.

Sweet potato can contribute to both nutritional and food security in Timor-Leste

Calorie malnutrition is chronic in Timor-Leste, where vitamin A deficiency is also common. Sweet potato (Ipomoea batatas L. (Lam.)) is a staple in cropping in Timor-Leste, of particular importance in the diet as household cereal stocks dwindle. This study tested if promising on-station results of introduced sweet potato clones were validated on-farm under farmer management across a wide range of agro-ecologies over the 2006–2007 and 2007–2008 growing seasons using participatory varietal selection. Additionally, as the clones differed in tuberous root flesh colour we evaluated their β-carotene content and, hence, potential contribution to the alleviation of Vitamin A deficiency. In the 2006–2007 growing season three introduced clones (later released as Hohrae 1, 2 and 3) significantly out-performed the local by 29–45%, while in the next season the yields of these clones were more than double that of the local. Whereas only 29% of farmers gave positive comments about the local cultivar, 66–71% of farmers commented positively on the Hohrae clones. We assessed the β-carotene content of five introduced clones, only light orange-fleshed tuberous roots had detectable levels of β-carotene (802–1209μg 100g−1). It was concluded that 221gd−1 – slightly less than 1 cupd−1 – of Hohrae 3 with light orange fleshed roots will meet the requirement of an individual with Vitamin A deficiency in Timor-Leste. With an improved production potential combined with substantial β-carotene, the clone Hohrae 3 has the potential to contribute to both calorie and Vitamin A deficits in Timor-Leste.