Sweet Potato Clones Research Articles

Reaction of sweet potato clones to the genre root knot nematodes Meloidogyne spp.

The use of sweet potato germplasm resistant to root nematodes has allowed breeding programs to obtain new and more productive cultivars resistant to pests and diseases, constituting an important alternative control. The objective of this study was to evaluate the response of clones of sweet potato (Ipomoea batatas (L.) Lamarck) for resistance to root knot nematodes of the genus Meloidogyne spp. and selecting resistant clones for use by producers or in breeding programs. The clones are from the Germplasm Bank of Embrapa Vegetables (CNPH) and are maintained in a clonal garden in Agua Limpa Farm at the University of Brasilia (FAL/UnB). The experiment was performed using an experimental design of randomized blocks in a simple arrangement, with 25 treatments and four replicates and six clones of sweet potatoes per plot. Among the clones, 87.5% showed resistance to Meloidogyne spp.

Gene action and heritability of yield components of dual-purpose sweetpotato clones

In the past, extensive research has been conducted on breeding sweetpotato [Ipomoea batatas (L.) Lam] varieties with improved fresh root yields. However, little attention has been paid to breeding the crop for both improved storage root and vine yields for mixed crop-livestock farming systems. Consequently, the objective of this study was to determine gene action and heritability (H) of vine and root yield, and related yield components in sweetpotato. Eight parents selected for their contrasting attributes of root and vine production were hand-crossed in a half-diallel. Thirty-six generated families were evaluated at Rubona, Karama and Ngoma research stations of the Rwanda Agriculture Board. General combining ability (GCA) and specific combining ability (SCA) mean squares were significant for fresh root yield (FRY), root dry matter content (RDMC), dry root yield (DRY), root-to-vine ratio, harvest index (HI) and vine dry matter content. GCA/SCA ratios were much greater than 0.5 for all the root parameters DRY, RDMC and FRY, with 0.75, 0.81 and 0.88, respectively, suggesting that additive gene action was more important than non-additive gene action. H estimates were above 0.5 for all tested parameters, with FRY, HI and RDMC having high estimates of 0.80, 0.81 and 0.92, in that order. Promising families were K5132/61 × Wagabolige, 2005-179 × RW11-1860, 4-160 × 2005-179, K5132/61 × RW11-1860, RW11-2910 × 2005-179, Ukerewe × SPK004 and Ukerewe × 4-160. Progenies derived from the selected families are recommended for further field testing in advanced selection stages at multiple sites for future release.

Combining ability and heterosis of selected sweetpotato (Ipomoea batatas L.) clones for storage root yield, yield-related traits and resistance to sweetpotato virus disease

Designed crosses using genetically diverse and complementary genotypes is useful to develop sweetpotato clones with improved agronomic traits. The objective of this study was to determine combining ability and heterosis among selected sweetpotato clones for number of storage roots per plant (NRPP), storage root yield (SRY), dry matter content (DMC) and resistance to sweetpotato virus disease (SPVD) for breeding. Eight selected genotypes were crossed using an 8 × 8 half diallel mating design to generate 28 families which were evaluated along their parents under field condition at three sites using a 6 × 6 lattice design with three replications. General combining ability (GCA) and specific combining ability (SCA) effects were highly significant (P < 0.001) among families. Significant GCA × sites and SCA × sites effects indicated environmental effect on gene action and expression. Parental genotypes Simama and Gairo had positive and significant GCA effects for NRPP. The parents 03-03, Ukerewe and Simama had significant and positive GCA effects for SRY and DMC, respectively. Further, Ex-Msimbu-1 and Gairo displayed negative and significant (P ≤ 0.01) GCA effect for SPVD resistance. The genotypes Gairo, 03-03, Ukerewe, Simama and Ex-Msimbu-1 are promising parents for sweetpotato breeding to improve NRPP, SRY, DMC and resistance to SPVD. Further, the study selected best performing families namely: 03-03 × Simama, 03-03 × Resisto and Simama × Ex-Msimbu-1 which recorded the highest mean storage root yields of 16.1, 16.6 and 17.2 tons/ha combined with high DMC and resistant to SPVD for genetic advancement.

Ефективність використання світлодіодів для клонального мікророзмноження батату та м’яти перцевої в культурі in vitro

The purpose. To determine efficiency of application of state-of-the-art LED-systems for clonal microreproduction in crop in vitro of individually selected, with high biochemical parameters of clones of sweet potato and peppermint. Methods. Methods of cultures of organs and tissues — culture of somatic tissues and cells, clonal microreproduction, measuring-weight, mathematical-statistical. Results. At use of light-emitting diode lamps of red and dark blue colors in tubed plants they observed increase of average length of shoot: for peppermint — on 31,2%, for sweet potato — on 10,6 % in comparison with control alternative (cultivation under luminescent lamps). The maximum multiplication ratio of peppermint has provided genotype M.r-17/4 — 7,5±0,6 pieces (control) and 7,9±0,6 pieces — cultivation under LED-lamps. At plants of sweet potato cultivated under light-emitting diode lamps owing to augmentation of length of internodes from 5,2 mm (control) to 6,7 mm the multiplication ratio has increased from 5,5 (control) to 5,8 pieces. Application of light-emitting diode lamps of red and dark blue colors for tubed clones of peppermint and sweet potato has provided tall multiplication ratio of perspective for selection and seeds growing of genotypes of well crops. Spectral make-up of light-emitting diodes according to biological features of crop and stage of morphogenesis requires the further optimization. Conclusions. Use of light-emitting diode lamps of red and dark blue colors placed on light-emitting diode tape in combination 2 1, provides necessary illuminance for growth of plants of tubed clones of peppermint and sweet potato at the stage of their mass reproduction and reduces expenses for the electric power for 62,5 %.

Pengelompokan Klon-Klon Ubi Jalar Berdasarkan Analisis Gerombol, Komponen Utama dan Biplot dari Karakter Morfologi

Sweet potato is a food crop with high genetic and phenotypic diversities. The objective of this study was to cluster sweet potato clones based on their morphological characters. This research used descriptive method using 25 morphological characters on 28 sweet potato clones and clustered using dice coefficient, principal component analysis and biplot analysis. The results showed that the clones were grouped into two clusters and 14 sub-clusters. Three sub-clusters had high similarity coefficients, i.e., 0.68-0.96, one clone was eliminated, and 11 sub-clusters had a low similarity, i.e., 0.41-0.52. The principal component analysis showed 14 of 25 morphological characters determined the diversity in 27 sweet potato clones with cumulative variance of 70.79%. Biplot analysis showed that 12 characters contributed to cumulative variance of 61.3%. Twelve morphological characters had weak contribution on the characteristics of the clones in quadrant I; meanwhile, characteristics of clones in quadrant II were orange, yellow and white tuber flesh, in quadrant III was dark purple tuber flesh, and in quadrant IV were purple tuber flesh and cortex. Result of the grouping analysis identified clones that were closely related and those distantly related for improvement purposes.Keywords: Ipomoea batatas, cumulative variance, Maluku province, morphology, relationship

Combining ability, gene action and heritability of weevil resistance, storage root yield and yield related-traits in sweetpotato

The objective of this study was to determine general combining ability (GCA), specific combining ability (SCA), gene action and heritability of weevil (Cylass spp.) resistance, dry matter content (DMC), yield and yield-related components of newly developed sweetpotato clones. Six weevil resistant and six susceptible parents were crossed using a 6 × 6 factorial mating design. The resultant 36 families were evaluated at three locations using a 3 × 12 lattice design with two replications for weevil resistance and yield and related traits in western Tanzania. The GCA effect for females was significant except for percentage marketable root number (PMRN) and percentage marketable root yield (PMRY). Significant GCA effect of males were detected for all traits except PMRY. The SCA effect of families was significant for all traits. With a general predicted ratio (GPR) > 0.5, additive gene action controlled more the expression of total root number (TRN), root yield (RY), DMC, percentage infested root number (PIRN), percentage infested root yield and weevil damage score (WDS), whereas non-additive gene action controlled more the expression of PMRN and PMRY with a < 0.5 GPR. The narrow sense heritability for TRN, RY, DMC, PIRN and WDS were 0.24, 0.56, 0.84, 0.62 and 0.62, while the broad sense heritability for these traits were 0.58, 0.72, 0.93, 0.78 and 0.77, in that order. Four female parents and four male parents were identified as the best general combiners and 13 families recorded the best performance for the evaluated traits. The high heritability for most of the traits studded and presence of both additive and non-additive gene action for the traits suggests that genetic gain can be realized through hybridization and clonal selection in breeding programs. The selected parents and families are useful genetic resources for the development of sweetpotato genotypes resistant to weevils and enhanced root yield, yield components and DMC.

Resistance response of fifteen sweet potato genotypes to scab disease (Sphaceloma batatas) in two growing sites in East Nusa Tenggara, Indonesia

Mau YS. 2018. Resistance response of fifteen sweet potato genotypes to scab disease (Sphaceloma batatas) in two growing sites in East Nusa Tenggara, Indonesia. Trop Drylands 2: 5-11. Field experiments were carried out in two growing locations involving potential sweet potato clones from East Nusa Tenggara Province, Indonesia to: (i) evaluate scab resistance levels of the sweet potato clones, and (ii) identify sweet potato clones with good resistance level to scab disease. The experiment was carried out in the fields employing a Randomized Block Design with a mono-factorial treatment design in each location. The treatment assigned was sweet potato genotype, each consisted of two replicates. The variables observed were disease severity that was assessed at 2, 4, 6, and 8 weeks after inoculation (WAI), which then was used to calculate the Area Under the Disease Progress Curve (AUDPC) of the disease severity. The ANOVA of AUDPC was used to determine the treatment effect, and the disease severity at 8 WAI was used to assess scab resistance level of the sweet potato genotypes tested. The study results showed highly significant differences of disease severities among the tested sweet potato genotypes within each trial location. The majority of the genotypes tested were classified "resistant" or "moderately resistant" to scab disease, except the check clone SLM-01 and KRA-01 that were, respectively, "susceptible" and "moderately susceptible" to scab disease. The majority of sweet potato genotypes evaluated were consistent in their resistance performance in the two trial locations.

UJI DAYA HASIL BEBERAPA KLON UBI JALAR (Ipomeae batatas L.)

This research aims to know the test results a few sweet potato clones. This research was conducted with a random Design Group (RAK) factorial design arranged in a random group of 6 sweet potato clones. As a factor of an experiment is a clone-clones the sweet potato i.e. BUS OP-OP, bus 61-4, OP 73-8, OP 73-5, D67 and 73-6/2. The data obtained were analyzed using analysis of variance and test difference between the average worked out with test BNT 5%. The observed parameters are the number of bulbs/plants, the fresh tuber weight kg/plant fresh weight, berangkasan,% dry weight of the dry weight of berangkasan, bulbs, bulbs, dry weight of the dry weight of the dry weight biomass, brangkasan, harvest index, tuber protein content (% BK). The results showed the potential results of the four new clones (bus BUS 61, OP-OP-4, OP 73-73 and OP. 8-5) has not yet reached optimal levels seen based on the level of results in control of the clones (D 67 and 73-6/2). While the range of protein content on clone-clones a new range 6.12-7.63% based on the dried weight won't be matter, whereas only control clones ranged from 2,19-3.30%.

Combining Ability, Heterosis, and Heritability of Storage Root Dry Matter, Beta-Carotene, and Yield-related Traits in Sweetpotato

Orange-fleshed sweetpotato (OFSP) is an effective, low-priced, and sustainable source of β-carotene (provitamin A). However, most OFSP varieties have low storage root dry matter content (DMC), which influences their acceptance by small-scale farmers and hence needs to be improved. The objective of the study was to determine the combining ability, type of gene action, heterosis and heritability of storage root DMC, β-carotene content, and yield-related traits of selected sweetpotato clones for further evaluation and breeding. Crosses were conducted using a 7 × 7 half-diallel mating design and a total of 28 genotypes (seven parents and 21 crosses) were evaluated at four locations in Ethiopia using a 7 × 4 alpha lattice design with two replications. The performance of the genotypes was significantly different (P &lt; 0.01) across the four locations for storage root DMC, β-carotene content, sweetpotato virus disease (SPVD) reaction, storage root yield, and harvest index (HI). The general combining ability (GCA) and specific combining ability (SCA) mean squares were significant (P &lt; 0.01) for all traits except the SCA effect of storage root DMC. The GCA to SCA variance ratios were 0.96, 0.94, 0.74, 0.96, and 0.97 for storage root DMC, β-carotene content, SPVD, fresh storage root yield, and HI, respectively, indicating that the inheritance of these traits was controlled mainly by additive genes. Progenies of crosses involving Ukerewe × Ejumula, Ukerewe × Pipi, Resisto × Pipi, and Ejumula × Pipi exhibited high levels of positive heterosis for storage root DMC. Similarly, progenies of crosses including Resisto × Pipi and Resisto × Ogansagan had higher positive heterosis for fresh storage root yield, reflecting the breeding value of these parents. Relatively high narrow sense heritability (h2) was obtained for β-carotene content (79.8%) and HI (48.6%). However, the h2 estimates of storage root DMC, SPVD, and fresh storage root yield were relatively low at 19.0%, 14.9%, and 20.4%, respectively. Crosses with high β-carotene content such as Ukerewe × Resisto, Resisto × Ogansagan, Eumula × Pipi, and NASPOT 1 × Temesgen exhibited high storage root DMC. These families also had medium-to-high mean fresh storage root yield. Therefore, progenies derived from these families are good candidates to develop improved OFSP varieties with high storage root DMC.

The Inheritance of Yield Components and Beta Carotene Content in Sweet Potato

Analysis of the gene action exhibited by an agronomic trait in crop plants is useful in the planning of an effective plant breeding program. This study sought to establish the inheritance variance of root yield components and beta carotene content present in sweet potato clones commonly grown in Kenya. Ten contrasting parents were selected based on their beta carotene content, dry matter content and yield potential. They were planted in pots in the green house at KEPHIS-Muguga, Kenya, where they were grafted into Ipomoea setosa to boost their ability to flower. Five parents were further selected based on their ability to flower under local environmental conditions and crossed in a 5 × 5 half diallel manner. Five parents and ten F1 clones arising from this hybridization were evaluated at KALRO-Kiboko, Kenya during two rainy seasons. The field trials were laid out in a randomized complete block design of three replications. The data were scored for root yield characteristics, beta carotene and root dry matter content. Griffing Method II, Model 1 diallel was used to estimate the general and specific combining ability. Genetic variability for beta carotene and root dry matter content indicated that the two traits were controlled mostly by both additive and dominant gene actions. Heterosis gene effects were found for beta carotene and root dry matter content which would be useful in the improvement of sweet potato productivity.

Características de raízes tuberosas de clones de batata-doce por meio de técnicas multivariadas para seleção de genótipos superiores

Objetivou-se avaliar características de raízes tuberosas de clones de batata-doce por meio de técnicas multivariadas para seleção de genótipos superiores, a presente pesquisa foi realizada na área experimental do Setor de Melhoramento Genético de Plantas do Centro de Ciências Agrárias da Universidade Federal de Alagoas. Foram avaliados 44 novos clones oriundos de progênies de meios-irmãos e irmãos germanos, além do cultivar Sergipana Vermelha, em linhas de 5 m de comprimento, no espaçamento de 1,0 m x 0,5 m, totalizando uma área total de 5 m²/clone. A colheita foi efetuada aos 120 dias após o plantio das ramas, em que foram avaliadas a produção de raízes tuberosas não comerciais (PRTNC), produção de raízes tuberosas comerciais (PRTC), produção total de raízes tuberosas (PTRT), número total de raízes tuberosas (NTRT), peso médio de raízes tuberosas comerciais (PMRTC), cor predominante da pele das raízes tuberosas (CPPERT) e cor predominante da polpa das raízes tuberosas (CPPORT). Foi utilizada a estatística descritiva, técnica de correlação e análise de componentes principais. Observou-se que os clones 23, 36, 17 e 37 apresentaram características agronômicas interessantes, sendo recomendados para o cultivo e na análise de componentes principais as variáveis PTRT e PRTC apresentaram maiores importâncias, refletindo que elas discriminam satisfatoriamente os clones.

Productivity, Dry Matter and Alcohol-Production Potential of Introduced Sweet Potato Clones

Productivity, Dry Matter and Alcohol-Production Potential of Introduced Sweet Potato Clones

In vitro iron bioaccessibility and uptake from orange-fleshed sweet potato (Ipomoea batatas (L.) Lam.) clones grown in Peru

Research to evaluate the potential of sweet potato to alleviate iron deficiency in affected human populations in developing countries is scarce. To partly fill this gap, we evaluated the bioaccessibility of iron in six sweet potato clones grown in two Peruvian environments, Satipo and San Ramon, following an in vitro gastro-intestinal digestion procedure. The bioaccessible iron content was clone-dependent and 1.7-fold higher in Satipo (5.15μg/g of fresh weight (FW)) as compared to San Ramon (3.04μg/g of FW). Aspects of iron bioavailability were then investigated using the Caco-2 cell model and ferritin synthesis as a marker, on two sweet potato clones after addition of an extrinsic source of iron to the digestion mixture.Results indicated that clone “CIP-194540.5” was presenting higher bioaccessible iron and lower phenolic contents and showed higher iron uptake as compared to clone “CIP-1055011.1” in both environments (91% vs. 24% in Satipo and 67% vs. 13% in San Ramon, respectively). These iron uptake values are higher than the ones previously reported for potato, which further stresses the use of sweet potato storage roots as part of a healthier diet in developing countries.

Karakter Agronomi dan Daya Hasil Tiga Klon Ubi Jalar Ungu (Ipomoea batatas) di Lahan Masam Lampung

Sweet potato is one of the alternative foods of rice that can be grown on a variety of soil conditions and almost fits on all altitude. Sweet potato clones with purple tuber contains anthocyanins which are antioxidants for our bodies. Purple sweet potato clones include: Varieties Ayamurasaki, Antin and local Purple Lampung. Ayamurasi is the introduction of the Japanese varieties, Antin was the result of the assembly and Purple Balitkabi Malang local is local varieties Lampung. To know the character of the growth and yield of sweet potato are three clones in acidic soil, it is necessary to test for these clones. This study was conducted at California State-owned plantation practices Lampung from May to November in 2011. The study used a randomized complete group (RKTL). Three clones of sweet potato used is Ayamurasaki Clones, Clone-1 and Clone Antin Local Purple Lampung, each repeated 4 times, so there are 12 experimental units. The data were analyzed by analysis of variance, and to know the difference between treatments done LSD a real level of 5% respectively. The conclusion of this research are: 1. There are differences between clones Antin agronomic character-1, Ayamurasaki, and Purple Local Lampung, 2. In acidic soil Lampung, Antin-1 clones are not resistant to stem borer attack and ladybugs (Omphisa anastomasalis), 3. Local Purple Clones Lampung has advantages in production and pest resistance, and has a good adaptation to the acidic soil Lampung, 4. Local Purple Lampung clones producing the highest production which amounted to 878.33 g per plant, followed by clones and clones Ayamurasaki Antin-1, each of which produces a production of 590 g and 166.67 g per plant Keywords: Character, Purple sweet potato, Acidic soil

Evaluation of candidate orange-fleshed sweetpotato clones for nutritional traits

ABSTRACTInformation on the nutrient contents of newly developed orange-fleshed sweetpotato (OFSP) varieties is required for recommendations to growers and the food industry. Therefore, the objectives of this study were to determine the nutritional value of newly developed OFSP clones and to establish the associations between β-carotene content and micro-nutrients for targeted large scale production to alleviate nutrient deficiencies. Seventeen OFSP and eight white/cream-fleshed sweetpotato clones were evaluated across six diverse environments (Halaba, Kokate, Areka, Arbaminch, Hawassa and Dilla) in southern Ethiopia in 2014 using a 5 × 5 simple lattice design. Nutritional traits data were collected on dry-weight basis and subjected to analysis of variance and correlation analyses. Environment, genotype, and genotype × environment interaction effects were highly significant (p < 0.01) for all parameters measured. A newly developed genotype, designated G8, had the highest contents of β-carotene (20.01 mg 100 g−1), protein (7.08%), iron (2.55 mg 100 g−1), zinc (1.42 mg 100 g−1), fructose (4.45%), glucose (5.34%) and sucrose (16.20%). Genotypes G15 and G19 also performed relatively well for the above nutritional traits. The three genotypes, G8, G15 and G19 had mean fresh root yield of 23.5,13.7 and 21.3 tha−1, respectively. These genotypes had root dry matter content of 26.99%, 25.23% and 33.09%, respectively. Β-carotene content had significant positive correlations with iron, zinc, fructose, glucose and sucrose content. This reflects the potential to breed for OFSP varieties enriched with the important micro-nutrients. Overall, the candidate OFSP clones, G8 (Resisto × PIPI-2), G15 (Resisto × Temesgen-23) and G19 (Resisto × Ogansagen-23) were good sources of nutritional traits such as vitamin A, iron, zinc, protein, sucrose, glucose and fructose. The selected genotypes can be recommended for large-scale production, food processing or further sweetpotato improvement to alleviate nutrient deficiencies in Ethiopia or similar environments in sub-Saharan Africa.

Performance of sweet potato clones for bioethanol production in different cultivation periods

Sweet potato is a perennial plant but cultivated as an annual crop. Thus, identifying the best period of cultivation is important for optimizing production, aiming human and animal consumption, as well as ethanol production. The aim of this work was to evaluate the performance of sweet potato clones grown in different cultivation periods for the production of bioethanol. Plots consisted of three cultivation periods (3, 5 and 7 months), and the subplots of five sweet potato clones (accessions IBP-007, IBP-038, IBP-075, IBP-079 and IBP-149) and the cultivar Brazlândia Rosada, considering a split plot scheme. We studied the root dry mass, starch and amylose content and starch and ethanol yield. Clone IPB-007 showed high values for starch yield (6.63 t/ha) and ethanol yield (4,379 L/ha). For root dry mass (38.32%) and starch (26.70%) and etha,nol yield (176.26 L/t), clone IPB-149 stood out. There was no significant difference for amylose content. Starch content (13.94%) and starch (1.64 t/ha) and ethanol yield (1,034 L/ha and 92.04 L/t) were lower for most of the clones in the three-month period of cultivation. We recommend the five-month period of cultivation and clones IPB-007 and IPB-149

Normal Seedlings as A New Parameter for Predicting Cross-Incompatibility Level on Sweetpotato

This research aimed to investigate the incompatibility levels of controlled cross-pollination in sweetpotato, based on normal seedling percentage and their correlation with seed vigour. The controlled cross-pollination in sweetpotato faces issues due to its cross-incompatibility and self-incompatibility characteristics. Currently, the incompatibility level in sweetpotato is investigated based on the fruit set percentage. However, this criterion lacks the ability in accurately predicting the number of new clones. Therefore, it is essential to study new parameters to create a better investigation of incompatibility in sweetpotato. The materials used in this research consisted of eight sweetpotato clones as female and four sweetpotato clones as male parents. Cross-pollinations were done reciprocally. The experiment was conducted at Indonesian Legume and Tuber Crops Research Institute from April to December 2014. The result showed that totally 5,188 times crossing produced about 25% fruit sets and 10% normal seedlings. The use of normal seedlings percentage as a new parameter in evaluating cross-pollination has apparently seemed to be more effective than the fruit sets percentage method because numbers of new clones could be known accurately. This research revealed that the normal seedling could be used as a new parameter in determining the incompatibility level in sweetpotato controlled cross-pollination.

Combining Ability, Maternal Effects, and Heritability of Drought Tolerance, Yield and Yield Components in Sweetpotato.

Knowledge on gene action and trait expression are important for effective breeding. The objective of this study was to determine the general combining ability (GCA), specific combining ability (SCA), maternal effects and heritability of drought tolerance, yield and yield components of candidate sweetpotato clones. Twelve genotypes selected for their high yield, dry matter content or drought tolerance were crossed using a full diallel mating design. Families were field evaluated at Masoro, Karama, and Rubona Research Stations of Rwanda Agriculture Board. Success rate of crosses varied from 1.8 to 62.5% with a mean of 18.8%. Family by site interaction had significant effect (P < 0.01) on storage root and vine yields, total biomass and dry matter content of storage roots. The family effects were significant (P < 0.01) for all parameters measured. Broad sense heritability estimates were 0.95, 0.84, 0.68, 0.47, 0.74, 0.75, 0.50, and 0.58 for canopy temperature (CT), canopy wilting (CW), root yield, skin color, flesh color, dry matter content, vine yield and total biomass, respectively. The GCA effects of parents and SCA effects of crosses were significant (P < 0.01) for CT, CW, storage root, vine and biomass yields, and dry matter content of storage root. The ratio of GCA/SCA effects for CT, CW, yield of storage roots and dry matter content of storage roots were higher than 50%, suggesting the preponderance of additive over non-additive gene action in the expression of these traits. Maternal effects were significant (P < 0.05) among families for CT, CW, flesh color and dry matter content, vine yield and total biomass. Across sites, the best five selected families with significant SCA effects for storage root yield were, Nsasagatebo × Otada 24, Otada 24 × Ukerewe, 4-160 × Nsasagatebo, K513261 × 2005-034 and Ukerewe × K513261 with 11.0, 9.7, 9.3, 9.2, 8.6 t/ha, respectively. The selected families are valuable genetic resources for sweetpotato breeding for drought tolerance, yield and yield components in Rwanda or similar environments.

Performance of sweet potato clones for starch and ethanol in three regions of the state of Sergipe, Brazil

Sweet potato (Ipomoea batatas L.) is a species that belongs to the family Convolvulaceae, and is originated from Central America and South America. As the growing conditions have great influence on the crop, the determination of harvesting time may vary with the cultivar, the growing region, or with the type of consumption (in natura or industrial). The aim of this work was to evaluate the performance of Ipomoea batatas L. clones, cultivated in three regions in the state of Sergipe, for starch and ethanol production. Thirty-one sweet potato clones grown in three municipalities of the state of Sergipe were tested in a randomized block design. The following variables were analyzed: root dry matter content (RDMC), root starch content (SC), starch yield (SY), ethanol yield (EY), and ethanol yield per ton of root (EYR). EY values ranged from 5910.39 to 8516.12 L ha-1; from 5141.85 to 6937.63 L ha-1; and from 5829.62 to 8211.77 L ha-1 in the municipalities of Sao Cristovao, Malhador, and Caninde de Sao Francisco, respectively, for clones IPB-075 and IPB-087 and cultivar Palmas. Estimates of heritability (h2) were above 50%. The values of the ratio between the coefficient of genetic variation (CVg) and the coefficient of environmental variation (CVe) for RDMC, SC, and EYR were high.

Stability Analysis of Fresh Root Yield of Sweetpotato in Southern Ethiopia using GGE Bi-Plot

The yield performance of sweetpotato is highly influenced by the effect of genotype by environment interaction (G x E) and stability analysis is required before variety release. The objectives of the study were to estimate the magnitude of G x E interactions, to select high yielding and stable elite sweetpotato clones, and to identify the most discriminating and representative test environments in Ethiopia. The study was conducted across six diverse environments in southern Ethiopia in 2014. The locations were Halaba, Kokate, Areka, Arbaminch, Hawassa and Dilla. Twenty five clones (24 elite clones and one check variety) were used for the study and were arranged in a 5 x 5 simple lattice design for field experimentation. Genotype plus Genotype by Environment Interaction (GGE Bi-plot) method was used to study the stability of the clones for fresh root yield. Significant environment, genotype and G x E interaction variances (p < 0.01) were observed for fresh root yield. The magnitude of environment and G x E interaction effect was higher than that of the genotype effect. Three clones, G1 (Ukrewe x Ejumula-10), G6 (Resisto x Ejumula-7) and G20 (Ejumula x PIPI-10) were identified as stable and relatively high yielding genotypes. The mean root yields of the three clones were 25.1, 26.9 and 25.5 t ha-1, respectively for G1, G6 and G20. Accordingly, the above three elite clones were selected for ultimate evaluation and recommendations. Among the test locations, the highest and stable mean fresh root yield of 37.1 t ha-1 was recorded at Arbaminch. Therefore, Arbaminch was identified as the best environment for sweetpotato production in southern Ethiopia. The study revealed the possibility of breeding sweetpotato varieties for high yielding and stable clones that have wide adaptation in southern and similar agro-ecologies in Ethiopia.