Sweetpotato

Permanent URI for this collectionhttp://104.225.218.216/handle/123456789/9

Articles in this collection include Cassava breeding, crop health, good agricultural practices, post harvest handling

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Decision tree scoring system to guide selection for consumer preference in sweetpotato breeding trials.
(Journal of The Science of Food and Agriculture, 2023-08-08) Mariam Nakitto; Reuben T Ssali; Suzanne D Johanningsmeier; Mukani Moyo; Henriette de Kock; Ingunn Berget; Julius J Okello; Sarah Mayanja; Samuel Edgar Tinyiro; Thiago Mendes; Yada Benard; Doreen Chelengat; Florence Osaru; Christophe Bugaud
BACKGROUND: Previously, a lexicon and protocol for quantitative descriptive analysis (QDA) was established for the Uganda sweetpotato breeding program. The implication of QDA scores for priority sensory attributes on consumer preference should be determined to interpret results efficiently and make decisions effectively. The present study aimed to develop a gender- responsive decision tree to obtain an overall sweetpotato eating quality score to facilitate demand-led targeted breeding selection. It focused on Kamuli and Hoima districts (Uganda) and uses pre-lease advanced clones (‘NKB3’, ‘NKB105’, ‘NKB135’, ‘D11’ and ‘D20’), released varieties (‘NASPOT 8’ and ‘NAROSPOT 1’) and landraces (‘Muwulu-Aduduma’, ‘Umbrella’). RESULTS: Including boiled sweetpotato sensory characteristics, namely mealy, sweet taste, sweetpotato smell, firm and not fibrous, in breeding design would benefit end-users, especially women given their role in varietal selection, food preparation and marketing. ‘D20’, ‘NASPOT 8’ and ‘NAROSPOT 1’ were most liked in both districts. ‘NKB3’ and ‘D11’ were the least liked in Hoima, whereas ‘Muwulu-Aduduma’ was the least liked in Kamuli. There was a positive correlation between color and overall liking (r2 = 0.8) and consumers liked the color (average rating ≥ 6 on a nine-point hedonic scale) of all genotypes. Threshold values (average rating on 11-point scales) for consumer acceptability were identified (sweet taste = 6, sweetpotato aroma and flavor = 6, firmness = 3, and mealiness = 4). A regression decision tree tool was created to calculate an eating quality selection index when screening lines in breeding programs using the values. CONCLUSION: Decision trees that include consumer needs and gender considerations would facilitate demand-led breeding and make varietal selection in sweetpotato breeding programs more effective.
Breeding Cultivars for Resistance to the African Sweetpotato Weevils, Cylas puncticollis and Cylas brunneus, in Uganda: A Review of the Current Progress
(Insects, 2023-10-25) Benard Yada; Paul Musana; Doreen M. Chelangat; Florence Osaru; Milton O. Anyanga; Arnold Katungisa; Bonny M. Oloka; Reuben T. Ssali; Immaculate Mugisa
In sub-Saharan Africa, sweetpotato weevils are the major pests of cultivated sweetpotato, causing estimated losses of between 60% and 100%, primarily during dry spells. The predominantly cryptic feeding behavior of Cylas spp. within their roots makes their control difficult, thus, host plant resistance is one of the most promising lines of protection against these pests. However, limited progress has been made in cultivar breeding for weevil resistance, partly due to the complex hexaploid genome of sweetpotato, which complicates conventional breeding, in addition to the limited number of genotypes with significant levels of resistance for use as sources of resistance. Pollen sterility, cross incompatibility, and poor seed set and germination in sweetpotato are also common challenges in improving weevil resistance. The accurate phenotyping of sweetpotato weevil resistance to enhance the efficiency of selection has been equally difficult. Genomics-assisted breeding, though in its infancy stages in sweetpotato, has a potential application in overcoming some of these barriers. However, it will require the development of more genomic infrastructure, particularly single-nucleotide polymorphism markers (SNPs) and robust next-generation sequencing platforms, together with relevant statistical procedures for analyses. With the recent advances in genomics, we anticipate that genomic breeding for sweetpotato weevil resistance will be expedited in the coming years. This review sheds light on Uganda’s efforts, to date, to breed against the Cylas puncticollis (Boheman) and Cylas brunneus (Fabricius) species of African sweetpotato weevil.
Heterotic gains, transgressive segregation and tness cost of sweetpotato weevil resistance expression in a partial diallel cross of sweetpotato
(Euphytica, 2023-08-27) Immaculate Mugisa; Jeninah Karungi; Paul Musana; Roy Odama; Milton O. Anyanga; Richard Edema; Paul Gibson; Reuben T. Ssali; Hugo Campos; Bonny M. Oloka; G. Craig Yencho; Benard Yada
Heterosis-exploiting breeding schemes are currently under consideration as a means of accelerating genetic gains in sweetpotato (Ipomoea batatas) breeding. This study was aimed at establishing heterotic gains, fitness costs and transgressive segregation associated with sweetpotato weevil (SPW) resistance in a partial diallel cross of sweetpotato. A total of 1896 clones were tested at two sites, for two seasons each in Uganda. Data on weevil severity (WED), weevil incidence (WI), storage root yield (SRY) and dry matter content (DM) were obtained. Best linear unbiased predictors (BLUPs) for each clone across environments were used to estimate het- erotic gains and for regression analyses to establish relationships between key traits. In general, low mid- parent heterotic gains were detected with the highest favorable levels recorded for SRY (14.7%) and WED (− 7.9%). About 25% of the crosses exhibited desirable and significant mid-parent heterosis for weevil resistance. Over 16% of the clones displayed superior transgressive segregation, with the highest percentages recorded for SRY (21%) and WED (18%). A yield penalty of 10% was observed to be associated with SPW resistance whereas no decline in DM was detected in relation to the same. Chances of improving sweetpotato through exploiting heterosis in controlled crosses using parents of mostly similar background are somewhat minimal, as revealed by the low heterotic gains. The yield penalty detected due to SPW resistance suggests that a trade-o may be necessary between maximizing yields and developing weevil-resistant cultivars if the current needs for this crop are to be met in weevil-prone areas.
Identification of the key morphological sweetpotato weevil resistance predictors in Ugandan sweetpotato genotypes using correlation and path-coefficient analysis
(Crop Science, 2023-03-16) Florence Osaru; Jeninah Karungi; Roy Odama; Doreen Murenju Chelangat; Paul Musana; Milton Anyanga Otema; Bonny Oloka; Paul Gibson; Richard Edema; Reuben Tendo Ssali; George Craig Yencho; Benard Yada
Sweetpotato weevils (SPWs) can cause up to 100% yield losses in sweetpotato (Ipomoea batatas). Nevertheless, there has been limited success in breeding for SPW resistance globally. This is attributed partly to difficulty in screening for resistance because resistance to the SPW is complex and is mediated by several resistance indicators. Measuring all these resistance indicators is costly and time consuming. To enhance efficiency in selection for SPW resistance, there is need to profile and identify key resistance indicators. Potentially, this will better enable breeders to timely and precisely select for SPW resistance. The objective of this study was to identify the most efficient morphological resistance indicators against SPW. Thirty sweetpotato genotypes that varied in resistance to SPW comprising local collections, released varieties, and breeding lines were evaluated at three locations for two seasons in Uganda using an alpha lattice design. Data were collected on storage root yield, SPW root and stem damage, and weevil resistance indicators such as vine vigor (VV), ground cover (GC), vine weight (VW), storage root neck length (NL), latex content, cortex thickness (CT), and dry matter content (DM). Genotype means for all mea- sured traits varied significantly except for CT. Negative relationships were observed between SPW root damage and GC, VW, CT, VV, NL, and DM. However, path coefficient analysis showed storage root NL (direct effect of −0.43, p < 0.001) as the most important morphological resistance indicator. Therefore, NL could be the most
Combining ability and heritability analysis of sweetpotato weevil resistance, root yield, and dry matter content in sweetpotato
(Frontiers in Plant Science, 2022-09-07) Immaculate Mugisa; Jeninah Karungi; Paul Musana; Roy Odama; Agnes Alajo; Doreen M. Chelangat; Milton O. Anyanga; Bonny M. Oloka; Iara Gonçalves dos Santos; Herbert Talwana; Mildred Ochwo-Ssemakula; Richard Edema; Paul Gibson; Reuben Ssali; Hugo Campos; Bode A. Olukolu; Guilherme da Silva Pereira; Craig Yencho; Benard Yada
Efficient breeding and selection of superior genotypes requires a comprehensive understanding of the genetics of traits. This study was aimed at establishing the general combining ability (GCA), specific combining ability (SCA), and heritability of sweetpotato weevil (Cylas spp.) resistance, storage root yield, and dry matter content in a sweetpotato multi-parental breeding population. A population of 1,896 F1 clones obtained from an 8 × 8 North Carolina II design cross was evaluated with its parents in the field at two sweetpotato weevil hotspots in Uganda, using an augmented row-column design. Clone roots were further evaluated in three rounds of a no-choice feeding laboratory bioassay. Significant GCA effects for parents and SCA effects for families were observed for most traits and all variance components were highly significant (p ≤ 0.001). Narrow-sense heritability estimates for weevil severity, storage root yield, and dry matter content were 0.35, 0.36, and 0.45, respectively. Parental genotypes with superior GCA for weevil resistance included “Mugande,” NASPOT 5, “Dimbuka- bukulula,” and “Wagabolige.” On the other hand, families that displayed the highest levels of resistance to weevils included “Wagabolige” × NASPOT 10 O, NASPOT 5 × “Dimbuka-bukulula,” “Mugande” × “Dimbuka-bukulula,” and NASPOT 11 × NASPOT 7. The moderate levels of narrow-sense heritability observed for the traits, coupled with the significant GCA and SCA effects, suggest that there is potential for their improvement through conventional breeding via hybridization and progeny selection and advancement. Although selection for weevil resistance may, to some extent, be challenging for breeders, efforts could be boosted through applying genomics-assisted breeding. Superior parents and families identified through this study could be deployed in further research involving the genetic improvement of these traits.
Bioactive compounds and antioxidant activities in peeled and unpeeled sweetpotato roots of different varieties and clones in Uganda
(Future Foods, 2022-12-10) Flora Christine Amagloh; Archileo N. Kaaya; Benard Yada; Doreen Murenju Chelangat; Arnold Katungisa; Francis Kweku Amagloh; Gaston Ampe Tumuhimbise
Rising incidences of non-communicable diseases (NCDs) in Sub-Saharan Africa (SSA) necessitates research into lo- cal functional foods, crucial in managing these conditions. This study aimed to investigate compositional changes in the bioactive compounds and antioxidant activities of peeled and unpeeled roots of Ugandan sweetpotato varieties with different flesh colours using spectrophotometric methods. Bioactive compounds and antioxidant activities, on dry weight basis were significantly higher (P<0.05) in unpeeled than peeled roots. Phenolic com- pounds were significantly higher (P = 0.001) in white, cream, and purple-fleshed roots (59.67–121.04 mg GAE/g) than in yellow and orange-fleshed roots (0.89–10.89 mg GAE/g). The deep orange-fleshed had the highest to- tal carotenoids (averagely 269.82 μg/g) and the white the lowest (averagely 8.36 μg/g). Total alkaloids in the sweetpotato roots ranged between 24.05 and 233.70 μg CE/g, below the potential toxicity range of 3–10 mg/g. The anthocyanin content of purple-fleshed roots was significantly higher (15.29 mg/g; P<0.001) than the other varieties, which ranged between 0.86 and 2.44 mg/g. Principal component analysis showed a stronger relation- ship between phenolics, anthocyanins, tannins, and ABTS radical scavenging antioxidant activity. Vitamin C and total carotenoids were more correlated with FRAP antioxidant activity. Consumption of different sweetpotato varieties with the peels could aid in managing NCDs in SSA.
Endemism and Reemergence Potential of the Ipomovirus Sweet Potato Mild Mottle Virus (Family Potyviridae) in Eastern Africa: Half a Century of Mystery
(Phytobiomes Journal, 2022-11-29) Arthur K. Tugume; Deusdedith R. Mbanzibwa; Titus Alicai; Christopher A. Omongo; M. N. Maruthi
Viruses have the ability to frequently colonize new hosts and ecological niches because of their inherently high genetic and evolutionary plasticity. However, a virus may emerge and remain of no or less economic importance until changes in viral or environmental factors dictate its epidemiological status. An example is sweet potato mild mottle virus (SPMMV), which was first reported in the 1970s on sweetpotato in eastern Africa. SPMMV has remained endemic in the region and poorly understood, yet accounting for 60 to 95% of losses, especially in mixed infections. Unlike other sweetpotato viruses which have global incidences, SPMMV has never been confirmed outside eastern Africa. This implicates the region as its center of origin but does not fully account for SPMMV’s exclusive geographic delimitation to eastern Africa. Despite its importance, several mysteries and research gaps surround SPMMV, which decelerate efforts for effective virus disease management in sweetpotato. The aim of this review is to articulate research gaps, propose pivotal scientific directions, and stimulate knowledge generation for better management of virus diseases in sweetpotato. Vector-mediated transmission of SPMMV remains enigmatic. Here, we postulate testable hypotheses to explain SPMMV transmission. Comparisons between SPMMV and cassava brown streak ipomoviruses demonstrate epidemiological “hallmarks” for monitoring SPMMV. Evolutionary forces on SPMMV coupled with the virus’ broad host range imply a “silent build up” of more fit variants in a changing climate, and this could explode into a worse disease conundrum. These information gaps need urgent filling to ease future management of virus disease emergences in sweetpotato.
Household Processing Methods and Their Impact on Bioactive Compounds and Antioxidant Activities of Sweetpotato Genotypes of Varying Storage Root Flesh Colours
(Antioxidants Journal, 2022-09-21) Flora C. Amagloh; Archileo N. Kaaya; Gaston A. Tumuhimbise; Arnold Katungisa; Francis K. Amagloh; Benard Yada
Sweetpotato storage roots, peeled and unpeeled, of varying flesh colours (white, cream, yellow, pale orange, deep orange, and purple) were spectrophotometrically evaluated for their bioac- tive compounds and antioxidant activities. Roots were boiled, steamed, baked, fried, or microwaved. The unpeeled roots had relatively higher (p < 0.001) bioactive compounds and antioxidant activ- ities than the peeled ones. All cooking methods increased phenolic compounds, flavonoids, and tannins in all genotypes. Significant losses of total carotenoids occurred with all cooking methods (ranging from 24.18 to 172.76 μg/g in raw sweetpotatoes vs. 10.06 to 118.17 μg/g in cooked ones; p < 0.001), except the deep-orange-fleshed genotype, in which frying slightly increased carotenoids from 269.81 to 304.74 μg/g. Microwaving retained 69% vitamin C in the cream-fleshed one, the high- est among the cooking methods. Anthocyanins decreased with baking and frying in the purple-fleshed one but increased with other methods; microwaving being highest at 13.9% (17.43 mg/g). While the 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid antioxidant activity decreased with all cooking techniques in some genotypes, ferricyanide-reducing antioxidant potential increased. The retention of bioactive compounds in sweetpotato storage roots depends on the processing method. Thus, to obtain the most health benefits, consumers should use different cooking methods but retain the peels.
Effect of Spent Mushroom Substrate and NPK Fertilizer on White and Orange-Fleshed Sweet Potato Varieties in South Eastern Nigeria
(National Agricultural Research Organisation, 2023-09-01) Ogbologwung L.P.; Okpara D.A.; Adedokun, O. M.
Spent mushroom substrate (SMS) and NPK (15:15:15) fertilizer were assessed under field conditions for their comparative effects on white and orange-fleshed sweet potato varieties in Umuahia southeastern Nigeria. The experiment was a split-split plot in randomized complete block design with three replicates. The main plot treatments were two sweet potato varieties (white-fleshed TIS87/0087 and orange-fleshed Umuspo 3). The split plot treatments were five NPK fertilizer rates (0, 100, 200, 300 and 400kg/ha) while the split-split plot treatments were three SMS levels (0, 2 and 4t/ha). Averaged across sweet potato varieties and NPK fertilizer, SMS significantly increased leaf area index, shoot biomass and storage root yield. Application of NPK fertilizer increased leaf area index and shoot biomass in both years and storage root yield in 2019. The white-fleshed TIS87/0087 variety produced significantly higher shoot biomass than Umuspo 3 in both years. TIS87/0087 had higher root yield than Umuspo 3 in 2018, but in 2019, the latter out yielded the former. Three-way interactions were significant for shoot biomass in 2018 and for storage root yield in both years. The highest shoot biomass (28.70 – 30.0t/ha) in 2018 was obtained from TIS87/0087 at moderate rates of 2t/ha SMS and 300kg/ha NPK fertilizer and from Umuspo 3 at 2t/ha SMS and 200kg/ha NPK fertilizer. The highest storage root yield 30.0t/ha was obtained from TIS87/0087 at 4t/ha SMS alone in 2018 and 37.1t/ha yield from Umuspo 3 at 4t/ha SMS only in 2019. The results showed that 4t/ha SMS was sufficient to promote high root yields in sweet potato in the area.

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