scholarly journals Modeling the impact of sweetpotato weevils on storage root yield

2018 ◽  
Vol 3 (1) ◽  
pp. 319-325
Author(s):  
Daniel A. Akansake ◽  
Putri E. Abidin ◽  
E. E. Carey

Abstract This study estimated the amount of loss in storage roots caused by various levels of damage caused by sweetpotato weevils (Cylas spp). Seven varieties of sweetpotato (Ipomoea batatas L. (Lam)) were evaluated in three production sites in northern Ghana for two years (2014 and 2015). Yield data for each experimental plot were collected. A regression analysis was carried out using the generalized linear model approach. In the study, nonmarketable roots were classified as all undersized roots (<100g) and spoilt roots due to weevil, millipede, and soft rot. The results indicated weevil damage as the only significant predictor of nonmarketable yield at 5% level of significance. From the study, the average values for total root yield, marketable root yield, and nonmarketable root yield were 9.39, 6.71, and 2.67 ton/ha respectively. The minimum weevil damage (score 2) resulted in a yield loss of 2 ton/ha which represents 8.3% while severe damage at score 9 could cause a loss of 7.43 ton/ha of storage roots representing 31% of the attainable yield of sweetpotato. Weevil susceptibility needs to be treated as a serious trait when evaluating sweetpotato genotypes to be released as varieties.

HortScience ◽  
2016 ◽  
Vol 51 (12) ◽  
pp. 1479-1481
Author(s):  
Desmond G. Mortley ◽  
Douglas R. Hileman ◽  
Conrad K. Bonsi ◽  
Walter A. Hill ◽  
Carlton E. Morris

Two sweetpotato [Ipomoea batatas (L.) Lam] genotypes (TU-82-155 and NCC-58) were grown hydroponically and subjected to a temporary loss of lighting in the form of 14 days of prolonged darkness compared with a lighted control under standard daily light periods to determine the impact on growth responses and storage root yield. Vine cuttings of both genotypes were grown in rectangular channels. At 65 days after planting, lights were turned off in the treatment chambers and replaced by a single incandescent lamp, providing between 7 and 10 µmol·m−2·s−1 photosynthetic photon flux (PPF) for 18 hours, and the temperature lowered from 28/22 °C light/dark, to a constant 20 °C. Plants remained under these conditions for 14 days after which the original light level was restored. Growth chamber conditions predark included, a PPF mean provided by 400-W metal halide lamps, of 600 ± 25 µmol·m−2·s−1, an 18-hour light/6-hour dark cycle and a relative humidity of 70% ± 5%. The nutrient solution used was a modified half-Hoagland with pH and electrical conductivity (EC) maintained between 5.5–6.0 and 1000–1200 μS·cm−1, respectively, and was adjusted weekly. Storage root number and fresh weight were similar regardless of treatments. Plants exposed to prolonged darkness produced 10.5% and 25% lower fibrous root fresh and dry mass, respectively, but similar foliage yield and harvest index (HI). ‘NCC-58’ produced an average of 31% greater storage root yield than that of ‘TU-82-155’ but the number of storage roots as well as % dry matter (%DM) were similar. ‘NCC-58’ also produced 31% greater fibrous root dry weight, whereas ‘TU-82-155’ produced a 44% greater HI. The significant interaction between prolonged darkness and cultivars for %DM of the storage roots showed that DM for ‘TU-82-155’ was 18.4% under prolonged darkness and 17.9% in the light. That for ‘NCC-58’ was 16.4% under prolonged darkness compared with 19.4% (14.8% greater) for plants that were not subjected to prolonged darkness. The evidence that there were no adverse impacts on storage root yield following the exposure to prolonged darkness suggests that the detrimental effects were below the detectable limits for these cultivars in response to the short perturbation in the available light and that sweetpotatoes would be hardy under short-term failure situations.


2011 ◽  
Vol 64 ◽  
pp. 160-167 ◽  
Author(s):  
S.L. Lewthwaite ◽  
P.J. Fletcher ◽  
J.D. Fletcher ◽  
C.M. Triggs

The sweetpotato (Ipomoea batatas) crop is propagated vegetatively by field transplanting adventitious sprouts produced on storage roots retained from the previous seasons harvest This system promotes the persistence and accumulation of both viruses and spontaneous mutations A phenomenon known as cultivar decline has been reported internationally where the root yield and appearance of commercially grown sweetpotato cultivars appear to deteriorate over successive growing seasons The relative contributions of virus infection and plant mutation to cultivar decline are uncertain but both issues are addressed through the use of virustested tissue cultured propagation systems This study assessed the degree of decline for cultivars Owairaka Red and Beauregard within the New Zealand biophysical production environment Storage root yield decreased significantly with increasing field exposure for both cultivars (P


2021 ◽  
Vol 11 (1) ◽  
pp. 013-021
Author(s):  
Sakhile Sipho Dlamini ◽  
Mzwandile Petros Mabuza ◽  
Bonginkhosi Edward Dlamini

Sweet potato (Ipomoea batatas L.) is the most grown storage root crop in Eswatini. However, its storage root yield is low among smallholder farmers partly due to use of inappropriate varieties and agronomic practices such as planting method. Thus, a field experiment was conducted at the University of Eswatini, Faculty of Agriculture, Luyengo, during 2019/2020 cropping season to determine the effects of planting method on growth and yield of the three sweet potato varieties. Two planting methods, namely horizontal and vertical; and three sweet potato varieties, namely Kenya-white, Ligwalagwala and Lamngititi were evaluated in a factorial arrangement in randomized complete block design in three replications. Results showed non-significant difference between the planting methods in most growth and yield parameters recorded for the sweet potato varieties. However, the vertical method of planting had relatively higher vine length, number of branches, mass of storage roots and storage root yield than the horizontal method. On the other hand, there were significant (P<0.05) differences among the sweet potato varieties for most of parameters recorded. The sweet potato variety Ligwalagwala had the highest vine length, number of storage roots per plant (6.47), mass of storage roots per plant (1137 g) and storage root yield (12.01 tonnes/ha). Thus, either horizontal or vertical method of planting and variety Ligwalagwala can be used to increase the productivity of sweet potato in the study area.


PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257703
Author(s):  
Yasin Bedrettin Karan ◽  
Özlem Gültekin Şanli

Sweet potato (Ipomoea batatas L.) cultivation in Turkey is concentrated in one province situated in Mediterranean region only, which would not fulfill the domestic needs of the country soon. Therefore, cultivation of the crop in other provinces/climatic regions should be initiated to fulfill the domestic needs. The cultivation in other provinces requires thorough assessment of yield and quality traits of target crop. Therefore, yield and quality characteristics of four sweet potato genotypes (i.e., ‘Hatay Kırmızısı’, ‘Hatay Yerlisi’, ‘Havuc’ and ‘Kalem’) were assessed in the current study in Kazova and Niksar counties of Tokat province of the country having middle Black Sea climate in field experiments during 2018 and 2019. The cuttings of the genotypes were planted in Niksar during the second fortnight of April and first week of May in Kazova. The planting density was kept 90 × 45 cm. Data relating to number of storage roots, storage root weight, storage root yield per hill and storage root yield per hectare were recorded. Furthermore, quality traits, including dry matter ratio (%), protein ratio (%) and antioxidant ratio (%) of storage roots were also determined. The highest total storage root yield was recorded for ‘Havuc’ genotype during both years and locations, followed by ‘Hatay Yerlisi’ and ‘Hatay Kırmızısı’ genotypes. Overall, storage root yield (60.06 and 62.40 tons ha-1 during first and second year) recorded for the experiment at Niksar was higher than the storage root yield recorded for Kazova experiment (53.50 and 52.84 tons ha-1 during first and second year, respectively). The highest dry matter was produced by ‘Kalem’ and ‘Hatay Yerlisi’ genotypes during both years and at both locations, followed by ‘Hatay Kırmızısı’ and ‘Havuc’ genotypes. The storage roots of the tested genotypes accumulated higher dry matter at Kazova during both years. The highest protein content was obtained from the ‘Kalem’ genotype, and the protein contents of the ‘Hatay Yerlisi’ and ‘Hatay Kırmızısı’ genotypes were close to the ‘Kalem’ genotype. The results indicated that tested genotypes can successfully be cultivated in middle Black Sea climate. Therefore, production of sweet potato can be initiated in the future to meet the domestic needs for sweet potato in the country.


Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 129-129 ◽  
Author(s):  
C. A. Clark ◽  
M. W. Hoy ◽  
J. P. Bond ◽  
C. Chen ◽  
Y.-K. Goh ◽  
...  

Bacterial root and stem rot of sweetpotato (Ipomoea batatas (L.) Lam.) was first fully characterized in the U.S. in 1977 (2). It was thought to be caused exclusively by Erwinia chrysanthemi. Although a previous report described sweetpotato as a host for E. carotovora subsp. carotovora, based on artificial inoculations, others have reported that neither E. carotovora subsp. carotovora nor E. carotovora subsp. atroseptica decay sweetpotato storage roots (1). In October 1995, storage roots of sweetpotato cv. Beauregard were received from St. Landry Parish, LA, that displayed typical bacterial root rot. Isolations from these roots yielded bacteria that showed a similarity of 0.945 to E. carotovora subsp. carotovora with the Biolog GN Bacterial Identification System (version 3.50). This isolate (Ecc-LH) also differed from isolates of E. chrysanthemi (Ech) from sweetpotato and other hosts in that it was insensitive to erythromycin, did not produce phosphatase or lecithinase, and did not produce gas from glucose. Ecc-LH differed from known strains of E. carotovora subsp. atroseptica in that it did not produce reducing substances from sucrose or acid from palatinose. When Beauregard storage roots were inoculated by inserting micropipette tips containing 50 μl of 1.0 × 108 CFU/ml, both Ecc-LH and Ech-48 produced typical bacterial root rot symptoms. However, when they were compared by infectivity titrations at 28 to 32°C, Ecc-LH was less virulent than Ech-48. Ecc-LH had an ED50 of approximately 1.0 × 106 CFU/ml and did not cause appreciable disease below inoculum concentrations of 1.0 × 105, whereas Ech-48 had an ED50 of approximately 1.0 × 108 and caused soft rot at the lowest concentration tested, 1.0 × 103. Similar disease incidence was observed in infectivity titrations at 22 to 24°C, but Ech-48 caused less severe soft rot. E. carotovora subsp. carotovora was reisolated from inoculated storage roots and its identity was reconfirmed by Biolog. When terminal vine cuttings of Beauregard were dipped in 1.0 × 108 CFU/ml and planted in a greenhouse, bacterial stem rot symptoms developed on plants inoculated with Ech-48 at about 4 weeks postinoculation, or when new growth began. However, no symptoms developed on plants inoculated with Ecc-LH. This is the first report of natural occurrence of E. carotovora subsp. carotovora causing bacterial root rot of sweetpotato in Louisiana. E. chrysanthemi remains the most important pathogen causing bacterial soft rot in sweetpotato since it is widely associated with sweetpotato, is more virulent on storage roots and also causes a stem rot. E. carotovora subsp. carotovora can cause root rot, but has been isolated in only one location to date, is less virulent on storage roots, and apparently does not cause stem rot on the predominant cultivar in U.S. sweetpotato production, Beauregard. References: (1) C. A. Clark and J. W. Moyer. 1988. Compendium of Sweet Potato Diseases. American Phytopathological Society, St. Paul, MN. (2) N. W. Schaad and D. Brenner. Phytopathology 67:302, 1977.


HortScience ◽  
1992 ◽  
Vol 27 (11) ◽  
pp. 1176d-1176
Author(s):  
Melvin R. Hall

Immersion of sweetpotato [Ipomoea batatas (L.)] storage roots in low concentration (5 and 50 mg·liter-1) of gibberellic acid (GA) in solutions of benzyl adenine plus GA4+7 increased early but not total plant production from bedded roots of `Georgia Jet' and `Jewel'. Immersion in 0.5 and 1 mg·liter-1 solutions of GA3 increased early plant production from `Georgia Jet'. Neither weight nor visual appearance of the harvested plants nor root yield from transplants were influenced by gibberellin treatments of the bedded roots.


HortScience ◽  
2019 ◽  
Vol 54 (5) ◽  
pp. 941-947
Author(s):  
Lauren Lindsey ◽  
Raymon Shange ◽  
Ramble O. Ankumah ◽  
Desmond G. Mortley ◽  
Sangita Karki

Organic fertilization techniques have become an attractive alternative to conventional techniques, but there remains interest in their impact on rhizosphere ecology. This study was aimed at assessing the impacts of various organic fertilizer amendments on storage root yield, chemical, biochemical, and microbial factors in the rhizosphere ecosystem and the bacterial community composition in the rhizosphere ecosystem. Four sweetpotato cultivars (J6/66, NCC-58, TU Purple, and Whatley/Loretan) and four organic fertilizer treatments [poultry litter, Megabloom (fish protein), NPK, and an untreated control] were used in the study. The experiments were conducted as a randomized complete block design with a 4 × 4 factorial treatment arrangement and three replications. Fertilizer treatments were split-applied at the rate of 134–67–67 kg·ha−1 NPK equivalent based on soil test recommendations 1 and 4 weeks after planting as single bands 15 cm from the plants and organic amendments were calculated based on total N content. Rhizosphere soil samples were collected at harvest and analyzed for soil pH, soil organic carbon (SOC), bacterial 16S rDNA, and selected soil enzymes. Organic amendments did not affect storage root yield or percent dry matter but enhanced both the mass and number of US#1 storage roots. Rhizosphere pH varied depending on cultivar and cultivar response varied with pH and ranged from 6.1 to 6.8, whereas SOC was similar regardless of the amendment. The impact of fertilizers was evident as Megabloom (fish protein) treatment suppressed the relative abundance (RA) of nitrifiers (Nitrosococcus and Nitrosomonadaceae). Also, the rhizosphere of ‘Whatley/Loretan’ seemed to have been a beneficial habitat for populations of common nitrogen-fixing bacteria Bradyrhizobium elkanii, and Rhodospirillaceae sp. as their RA increased significantly in the rhizosphere. That bacteria associated with carbon and nitrogen cycling under aerobic conditions were found to be ubiquitous in the rhizosphere of sweetpotato, suggesting that certain amendments positively impacted the populations of nitrogen-cycling bacteria, thus making them a viable alternative to NPK when considering increasing or sustaining yield while promoting long-term soil health.


Plant Disease ◽  
2002 ◽  
Vol 86 (6) ◽  
pp. 695-695 ◽  
Author(s):  
G. J. Holmes ◽  
C. A. Clark

In October 1997, samples of diseased sweetpotato (Ipomoea batatas (L.) Lam.) roots from storage were submitted for diagnosis to the Plant Disease and Insect Clinic at North Carolina State University. Two organisms were detected from soft rotted roots: Rhizopus stolonifer (Ehrenb.:Fr.) Vuill. (cause of Rhizopus soft rot) and Geotrichum candidum Link. Attempts to duplicate a soft rot by stab-inoculation of sweetpotato roots with a pure culture of G. candidum were unsuccessful. In Louisiana, following heavy rains due to Tropical Storm Frances in 1998, sweetpotato roots exhibiting a cortical tissue collapse at time of harvest were submitted to Louisiana State University for disease identification. Isolations from lesion margins consistently yielded G. candidum. Attempts to reproduce the disease by stab-inoculation produced only a few restricted lesions 5 to 15 mm in diameter. In 1999, rains from hurricanes Dennis, Floyd, and Irene caused extensive flooding in sweetpotato-growing areas of the North Carolina Coastal Plain. Extensive losses occurred in many fields due to a condition known as “souring,” and G. candidum was frequently detected sporulating on the surface of soured roots. This provided a clue for reproducing the disease artificially (1). In 2000, the disease was successfully reproduced. Sterile, wood toothpicks were dragged across a pure culture of G. candidum and inserted (1.5 cm deep) into the mid-section of sweetpotato (cv. Beauregard) roots. Roots were submerged in water at room temperature (23°C) for 24 to 48 h. Each of four roots was inoculated four times, and sterile toothpicks were stabbed into the controls. Additional controls consisted of an inoculated root that was not submerged in water, and a root that was not wounded or inoculated but submerged in water. Following submersion, roots were incubated at room temperature for 5 days. The experiment was repeated. Isolations from diseased tissues consistently yielded G. candidum. Symptoms consisted of slightly sunken, circular lesions, typically 15 to 50 mm in diameter. In cross-section, diseased tissue surrounding the wound was darkened, soft (but not watery), and extended 1 to 20 mm on either side of the wound. None of the controls showed signs of decay. These symptoms are consistent with but do not represent the full range of symptoms observed in the field. Souring of sweetpotato is likely the result of a complex of factors including predisposition of roots by water-saturated soil and the pathogenic effects of G. candidum. To our knowledge, this is the first known report of rot caused by G. candidum on sweetpotato in the United States. G. candidum was reported on sweetpotato in India, but no pathogenicity tests were reported (2). References: (1) E. Cohen and J. W. Eckert. Plant Dis. 75:166, 1991. (2) N. C. Mandal and M. K. Dasgupta. Indian J. Mycol. Plant Pathol. 10:31, 1980.


2015 ◽  
Vol 25 (6) ◽  
pp. 815-823 ◽  
Author(s):  
David Wees ◽  
Philippe Seguin ◽  
Josée Boisclair ◽  
Chloé Gendre

There is an increased interest in producing sweetpotato (Ipomoea batatas) in parts of eastern Canada, which are farther north and have fewer growing degree days (GDD) than traditional production regions in the southern United States. There is currently little information on cultivar selection for farmers in these northern regions. We evaluated yields and quality of 15 sweetpotato cultivars and selected lines grown with black plastic mulch but without pesticides. The best marketable yields (18–25 t·ha−1) in this trial were comparable to average marketable yields obtained in traditional sweetpotato-producing regions. Of the orange-fleshed cultivars and selected lines, Beauregard, B94-24, and Evangeline had high yields and warrant further testing. Covington, a common cultivar in North Carolina and Ontario, had poor yields in our conditions: it may require more GDD. ‘Porto Rico’ and ‘Ginseng Red’ had poor yields mainly because their storage roots were too small. The yellow-fleshed ‘Georgia Jet’ and GJ2010 had very vigorous vines and produced high yields, but had a high culling rate because of malformed or cracked storage roots. The white-fleshed ‘Murasaki-29’, ‘O’Henry’, and ‘Japanese’ also had high yields; whereas ‘White Travis’ and ‘Korean Purple’ had poor yields with small storage roots. Establishing the crop with rooted transplants instead of slips was satisfactory as long as the transplants were less than 4 weeks old. On the basis of our limited data, the following cultivars and selected lines may be suitable for Quebec, Canada: Beauregard, B94-24, Evangeline, Georgia Jet, GJ2010, and Murasaki-29. ‘Evangeline’ and ‘Covington’ had higher soluble solid contents than the other cultivars. High percent soluble solids may be desired by consumers. In spite of the absence of pesticides, very few pest or disease problems were observed except for some postharvest soft rot.


2009 ◽  
Vol 62 ◽  
pp. 402-402
Author(s):  
S.L. Lewthwaite ◽  
P.J. Wright

The predominant diseases of the commercial kumara (Ipomoea batatas) or sweetpotato crop are caused by fungal pathogens The field disease pink rot results from infection by the fungus Sclerotinia sclerotiorum Lesions form on vines but may spread down stems to the roots The widespread nature of this disease in sweetpotato appears peculiar to New Zealand Scurf is a disease caused by Monilochaetes infuscans which occurs in the field but may proliferate amongst stored roots The disease causes a superficial discolouration of the root surface which is mainly cosmetic but can also increase root water loss in storage Infection by Ceratocystis fimbriata produces a disease known as black rot The disease can be transmitted amongst plants at propagation but is particularly rampant amongst roots in storage This disease is readily transmitted and can cause severe economic loss Fusarium oxysporum causes surface rots in stored roots characterised by light to dark brown lesions that tend to be firm dry and superficial The lesions may be circular and centred on wounds caused by insects or mechanical damage at harvest Soft rot caused by Rhizopus stolonifer generally occurs in roots after they are washed and prepared for the market Fungal infection occurs through wounds or bruised tissue producing distinctive tufts of white fungal strands and black spores


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