Cultivar Decline in Sweetpotato: I. Impact of Micropropagation on Yield, Storage Root Quality, and Virus Incidence in `Beauregard'

Decline in sweetpotato yield and storage root quality has been attributed to the accumulation of viruses, pathogens and mutations. To document the effects of decline on yield and storage root quality, two micropropagated, virus-indexed, greenhouse produced G1 `Beauregard' meristem-tip cultured clones, B94-14 and B94-34, were compared with 1) micropropagated B94-14 and B94-34 clones propagated adventitiously up to five years in the field (G2, G3, G4, G5); and 2) nonmicropropagated, unimproved stock of `Beauregard' seed in field trials during 1997 to 2001. At least three trials were located each year in sweetpotato producing regions in North Carolina. In 2000 and 2001, two trials were monitored weekly for foliar symptoms of Sweet potato feathery mottle virus (SPFMV) and other potyviruses, and virus-indexed for selected viruses using Ipomoea setosa and nitrocellulose enzyme linked immunosorbant assays (NCM-ELISA). Only SPFMV was detected in field samples using NCM-ELISA, but this does not rule out the presence of newly described viruses infecting sweetpotato for which tests were unavailable. Monitoring indicated that all G1 plants became infected with SPFMV by the end of the growing season, and that G2 to G5 plants were probably infected in their initial growing season. G1 plants consistently produced higher total yield, total marketable yield (TMY), U.S. No. 1 root yield and percent No. 1 yield than G2 to G5 plants. G1 plants also produced storage roots with more uniform shapes and better overall appearance than storage roots produced from G2 to G5 plants. Also, G2 to G5 storage roots tended to be longer than G1 storage roots. Rank mean yield and storage root quality measurements of each location were consistent with means averaged over locations per year and suggested a decrease in yield and storage root quality with successive seasons of adventitious propagation. Linear regression analysis used to model yield and storage root quality measurements of seed generations G1 to G5 indicated that total yield, TMY, No. 1 yield, percent No. 1 yield, shape uniformity, and overall appearance decreased gradually, and that length/diameter ratios increased gradually with generation. The rate of decline in No. 1 yield was greater for B94-34 compared to B94-14. Both viruses and mutations of adventitious sprouts arising from storage roots probably contribute to cultivar decline in sweetpotato, but further studies are needed to determine their relative importance. A simple profitability analysis for G1 vs. G2-G4 planting material conducted to facilitate better understanding of the economics of using micropropagated planting material to produce a crop in North Carolina revealed that growers have a potential net return of $2203/ha for G1 plants, $5030/ha for G2 plants, and $4394/ha for G5 plants. Thus, while G1 plants generally produce higher No. 1 yields, a greater monetary return can be achieved using G2 planting materials because of the high costs associated with producing G1 plants. Based on this analysis, the best returns are accrued when growers plant their crop using G2 and/or G3 seed.

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Effects of Halosulfuron POST on Sweetpotato Yield and Storage Root Quality

Weed Technology ◽

10.1614/wt-d-11-00175.1 ◽

2013 ◽

Vol 27 (1) ◽

pp. 113-116 ◽

Cited By ~ 4

Author(s):

Peter J. Dittmar ◽

David W. Monks ◽

Katherine M. Jennings ◽

Jonathan R. Schultheis

Keyword(s):

Total Yield ◽

Field Studies ◽

Controlled Environment ◽

Storage Root ◽

Storage Roots ◽

And Storage ◽

External Injury ◽

Root Quality

Field studies were conducted to determine the effect of halosulfuron at 0, 13, 26, 39 or 52 g ha−1 applied 10, 22, and 31 d after planting (DAP) on ‘Beauregard' and ‘Covington' sweetpotato. Storage roots were harvested, graded, cured, and stored in controlled environment for 2 mo. Where injury on storage roots was observed, external injury occurred on the surface of the storage root as a blackened area with blistering and internal injury consisted of small red-brown spots inside the sweetpotato storage root. Total yield of sweetpotato with 13 g ha−1 halosulfuron treatment (155,157 kg ha−1) was similar to the nontreated check (162,002 kg ha−1). However, halosulfuron rates above 13 g ha−1 resulted in a reduction of marketable grade roots and total yield of sweetpotato. Regardless of rate and timing of halosulfuron, external and internal injury to Beauregard storage roots was less than 6 and 9%, respectively. No external injury to Covington was observed from all rates of halosulfuron applied POST at 10 DAP. Halosulfuron at 22 DAP to Covington caused greater external injury to storage roots than was observed on the nontreated. Thus, Beauregard appears more tolerant to halosulfuron POST than Covington. To minimize internal or external injury to storage roots of Covington, halosulfuron must be applied within 10 DAP.

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Sweetpotato Transplant Holding Duration Effects on Plant Survival and Yield

HortTechnology ◽

10.21273/horttech03808-17 ◽

2017 ◽

Vol 27 (6) ◽

pp. 818-823 ◽

Cited By ~ 1

Author(s):

William B. Thompson ◽

Jonathan R. Schultheis ◽

Sushila Chaudhari ◽

David W. Monks ◽

Katherine M. Jennings ◽

...

Keyword(s):

North Carolina ◽

Ipomoea Batatas ◽

Storage Root ◽

Storage Roots ◽

Higher Plant ◽

Root Numbers ◽

Dry Conditions ◽

Plant Stand ◽

And Storage ◽

Lower Plant

Studies were conducted in North Carolina to determine the effect of holding durations (HDs) [0, 1, 3, 5, and 7 days before planting (DBP)] of ‘Covington’ sweetpotato (Ipomoea batatas) transplants on plant stand and storage root numbers and yield in production fields. In a second field study, the effect of preplant irrigation (PI) treatments (PI and nonirrigation) were evaluated along with the transplant HD on plant stand, storage root numbers, and yield. Transplants held for 7 DBP did not survive as well as the other treatments (lower plant stands) and had lower no. 1, marketable, and total storage root numbers and yields than other holding treatments. HD of 1 or 3 DBP resulted in higher plant stands, and no. 1, marketable, and total numbers of storage roots and yields than holding for 0, 5, or 7 DBP. This study affirms the importance of soil moisture at and shortly after planting for transplant survival and yield. Holding transplants for 1–3 DBP can improve stand establishment and yields when dry conditions occur either before or soon after planting. However, holding transplants for 7 DBP can result in reduced plant stands and yields when stress/dry conditions occur soon after planting.

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Response of sweetpotato to pendimethalin application rate and timing

Weed Technology ◽

10.1017/wet.2019.103 ◽

2019 ◽

Vol 34 (2) ◽

pp. 301-304

Author(s):

Stephen L. Meyers ◽

Sushila Chaudhari ◽

Katherine M. Jennings ◽

Donnie K. Miller ◽

Mark W. Shankle

Keyword(s):

North Carolina ◽

Field Trials ◽

Application Rate ◽

Storage Root ◽

Application Timing ◽

Crop Tolerance ◽

Valuable Addition ◽

Crop Injury ◽

And Storage ◽

Root Quality

AbstractField trials were conducted near Pontotoc, Mississippi; Chase, Louisiana; and Clinton, North Carolina, in 2017 and 2018 to determine the effect of pendimethalin rate and timing application on sweetpotato crop tolerance, yield, and storage root quality. Treatments consisted of five pendimethalin rates (266, 532, 1,065, 1,597, and 2,130 g ai ha−1) by two application timings (0 to 1 or 10 to 14 d after transplanting). Additionally, a nontreated check was included for comparison. Crop injury (stunting) was minimal (≤4%) through 6 wk after transplanting (WAP) and no injury was observed from 8 to 14 WAP, regardless of application timing or rate. The nontreated check yielded 6.6, 17.6, 5.5, and 32.1 × 103 kg ha−1 of canner, no. 1, jumbo, and total grades, respectively. Neither pendimethalin application timing nor rate influenced jumbo, no. 1, marketable, or total sweetpotato yield. Overall, these results indicate that pendimethalin will be a valuable addition to the toolkit of sweetpotato growers.

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Sugar beet response to different K, Na and Mg ratios in applied fertilizers

Plant Soil and Environment ◽

10.17221/809/2017-pse ◽

2018 ◽

Vol 64 (No. 4) ◽

pp. 173-179

Author(s):

Barłóg Przemysław ◽

Szczepaniak Witold ◽

Grzebisz Witold ◽

Pogłodziński Radosław

Keyword(s):

Sugar Beet ◽

Field Experiments ◽

Growing Season ◽

Simultaneous Increase ◽

Storage Root ◽

Optimum Ratio ◽

Rate Reduction ◽

Total Rate ◽

Storage Roots ◽

Root Quality

Potassium (K) in sugar beet can be partly replaced by magnesium (Mg) and sodium (Na). This hypothesis was verified based on 12 field experiments conducted on four farms in Poland during the seasons 2010–2012. The effect of different K, Na and Mg ratios in fertilizers applied in the total rate of 3205 mol/ha on beet yield (BY), storage root quality and white sugar yield (WSY) was determined. The tested K:Mg:Na cation ratios were as follows: 1:0:0; 1:0.11:0.09; 1:0.16:0.54 and 1:0.33:2.19. BY and WSY were affected by the total rate of the applied cations. The optimum ratio of K:Mg:Na was different with respect to the site and the growing season. The K rate reduction from 125 to 24 kg/ha combined with the simultaneous increase in the rate of Mg and Na did not result in lower BY. However, a too narrow K:Na ratio in applied fertilizers resulted in a decrease of sucrose content in storage roots. The fertilization cost for sugar beet production could be reduced through the application of fertilizers that contain fixed amounts of Na on soils rich in available K.

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Response of sweetpotato to diquat applied pretransplanting

Weed Technology ◽

10.1017/wet.2020.27 ◽

2020 ◽

Vol 34 (5) ◽

pp. 637-641

Author(s):

Stephen L. Meyers ◽

Katherine M. Jennings ◽

Donnie K. Miller ◽

Mark W. Shankle

Keyword(s):

North Carolina ◽

Field Trials ◽

Storage Root ◽

Crop Tolerance ◽

Crop Injury ◽

And Storage ◽

Root Quality

AbstractField trials were conducted in North Carolina in 2017 and Louisiana and Mississippi in 2018 to determine the effect of pretransplanting applications of diquat on sweetpotato crop tolerance, yield, and storage root quality. In North Carolina treatments consisted of two rates of diquat (560 or 1,120 g ai ha−1) alone or mixed with 107 g ai ha−1 flumioxazin and applied 1 d before transplanting (DBP), sequential applications of diquat (560 or 1,120 g ha−1) 1 and 17 DBP, 107 g ha−1 flumioxazin alone, and a nontreated check. In Louisiana and Mississippi treatments consisted of diquat (560 or 1,120 g ha−1) applied 1 DBP either alone or followed by (fb) rehipping rows or 107 g ha−1 flumioxazin immediately prior to transplanting. Additional treatments included 546 g ha−1 paraquat applied 1 DBP and a nontreated check. In North Carolina injury was ≤3% for all treatments through 23 d after transplanting (DAP), and no injury was observed after 23 DAP. Visual sweetpotato stunting pooled across the Mississippi and Louisiana trials ranged from 1% to 14%, 0% to 6%, and 0% to 3% at 2, 4, and 6 wk after planting (WAP), respectively, and no crop injury was observed after 6 WAP. Diquat applied 1 DBP and not fb rehipping resulted in greater crop injury (12%) than comparable treatments that were rehipped (2%). In North Carolina single and sequential diquat applications resulted in reduced No. 1 sweetpotato yield (24,230 and 24,280 kg ha−1, respectively) compared with the nontreated check, but No. 1 yield when diquat plus flumioxazin (26,330 kg ha−1) was used was similar to that of the nontreated check. No. 1 yield did not differ by treatment in Louisiana and Mississippi.

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Occurrence, Severity and Initiation of Internal Necrosis in ‘Covington’ Sweetpotato

HortTechnology ◽

10.21273/horttech.25.3.340 ◽

2015 ◽

Vol 25 (3) ◽

pp. 340-348 ◽

Cited By ~ 1

Author(s):

Chen Jiang ◽

Penelope Perkins-Veazie ◽

Sylvia M. Blankenship ◽

Michael D. Boyette ◽

Zvezdana Pesic-VanEsbroeck ◽

...

Keyword(s):

North Carolina ◽

Relative Humidity ◽

Ipomoea Batatas ◽

Storage Temperature ◽

The State ◽

Storage Root ◽

Storage Roots ◽

Harvest Aid ◽

Internal Necrosis ◽

Storage Facilities

A series of studies were conducted to better understand the occurrence and causes of internal necrosis (IN) in ‘Covington’ sweetpotato (Ipomoea batatas). Assessment of the problem among the industry was done for 2 years and revealed that IN was widespread in commercial storage facilities throughout the state of North Carolina; both incidence and severity were generally low (<10% incidence with minimal severity of symptoms). A few storage rooms had a high percentage of IN with severe storage root symptoms but results were inconsistent across years and among rooms. Preharvest studies with commercially used insecticides did not induce IN, but the harvest aid ethephon consistently induced IN with an incidence higher than 50%. Internal necrosis symptoms were not detectable at harvest, and earliest consistent incidence was observed 6 days after harvest (DAH) during the curing phase. Symptoms became more prevalent and severe at 30 DAH. However, in commercial storage rooms, no relationship was found between IN incidence and postcuring storage temperature or relative humidity (RH) conditions. Sweetpotato storage roots stored in air-tight barrels and exposed to 100 ppm ethylene after curing showed no relationship between the presence of ethylene gas in storage and incidence of IN. Our results indicate that IN incidence of ‘Covington’ is erratic with no obvious cause among storage rooms and that initiation of IN may occur most frequently during the first week following harvest.

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Cold Acclimation Attributes of Two Asparagus Cultivars with Varying Patterns of Fern Senescence

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.136.3.177 ◽

2011 ◽

Vol 136 (3) ◽

pp. 177-189 ◽

Cited By ~ 9

Author(s):

Erik J. Landry ◽

David J. Wolyn

Keyword(s):

Cold Acclimation ◽

Nitrogen Concentration ◽

Chlorophyll Concentration ◽

Sampling Period ◽

Asparagus Officinalis ◽

Cultivar Differences ◽

Low Molecular Weight ◽

Storage Root ◽

Storage Roots ◽

And Storage

Adequate winterhardiness is crucial for yield stability of asparagus (Asparagus officinalis) cultivars in southern Ontario, Canada, and could be influenced by pattern of the fall fern senescence. Fern of cultivar Guelph Millennium (GM) turns yellow or senesces by mid-October, before that of cultivar Jersey Giant (JG), which often remains green until a killing frost. Early fern senescence could be a signal for cold acclimation competency and consequently winterhardiness, explaining the superior stand longevity and yield observed for GM compared with JG. A field experiment was conducted from mid-August to November to measure physiological parameters related to cold acclimation in fern, rhizome, and storage roots. During fall, fern chlorophyll concentration, rhizome nitrogen concentration, percent water of the crown, and storage root LT50 (temperature at which 50% cell death occurs) decreased. Cultivars did not differ for storage root percent water; however, values were smaller (greater dehydration) for GM than JG in the rhizome. At the end of the sampling period, GM had higher and lower concentrations of rhizome low-molecular-weight, non-structural carbohydrates and sucrose, respectively, than JG, which could support a hypothesis of greater winterhardiness in GM. Storage root LT50 values of –19 °C and the lack of cultivar differences for this trait, in conjunction with differences between GM and JG for rhizome traits thought to be important for freezing tolerance, suggest characteristics of the rhizome in conjunction with timing of fern senescence may be important in cold acclimation of asparagus.

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Sweetpotato `Beauregard' Mericlones Vary in Yield, Vine Characteristics, and Storage Root Size and Shape Attributes

HortScience ◽

10.21273/hortsci.38.6.1089 ◽

2003 ◽

Vol 38 (6) ◽

pp. 1089-1092 ◽

Cited By ~ 2

Author(s):

A.Q. Villordon ◽

J.M. Cannon ◽

H.L. Carroll ◽

J.W. Franklin ◽

C.A. Clark ◽

...

Keyword(s):

Ipomoea Batatas ◽

Maximum Yield ◽

Storage Root ◽

Storage Roots ◽

Marketable Yield ◽

Methods Of Evaluation ◽

Foundation Seed ◽

Axis Length ◽

And Storage ◽

Selection Of

Yield tests and evaluation of selected storage root and vine characters were conducted among 12 `Beauregard' sweetpotato [Ipomoea batatas (L.) Lam.] mericlones. Maximum yield differences were 43%, 48%, 79%, and 40% for U.S. #1, canners, jumbos, and total marketable yield, respectively. Additive main effect and multiplicative interaction (AMMI) biplot analysis was useful in graphically presenting the yield differences and stability patterns of mericlones. Differences were also detected in vine length, internode diameter, and internode length. Digital image analysis of U.S. #1 storage roots also revealed differences in storage root minor axis length, roundness, and elongation attributes. The results provide valuable information for enhancing current methods of evaluation and selection of mericlones for inclusion in sweetpotato foundation seed programs.

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Sweetpotato Response to Reduced Rates of Dicamba

Weed Technology ◽

10.1017/wet.2021.65 ◽

2021 ◽

pp. 1-15

Author(s):

Mark W. Shankle ◽

Lorin M. Harvey ◽

Stephen L. Meyers ◽

Callie J. Morris

Keyword(s):

Field Study ◽

Growing Season ◽

Additional Treatment ◽

Storage Root ◽

Root Yield ◽

Target Movement ◽

Marketable Yield ◽

Crop Tolerance ◽

Plant Injury ◽

And Storage

A field study was conducted in Mississippi to determine the effect of reduced dicamba rates on sweetpotato crop tolerance and storage root yield, simulating off-target movement or sprayer tank contamination. Treatments were a non-treated control and four rates of dicamba [70 g ae ha−1 (1/8X), 35 g ae ha−1 (1/16X), 8.65 g ae ha−1 (1/64X) and 1.09 g ae ha−1 (1/512X)] applied either 3 days before transplanting (DBP) or 1, 3, 5, or 7 weeks after transplanting (WAP). An additional treatment consisted of 560 g ae ha−1 (1X) dicamba applied 3 DBP. Crop injury ratings were taken 1, 2, 3, and 4 weeks after treatment (WAT). Across application timings, predicted sweetpotato plant injury 1, 2, 3, and 4 WAT increased from 3 to 22%, 3 to 32%, 2 to 58%, and 1 to 64% as dicamba rate increased from 0 to 70 g ha−1 (1/8X), respectively. As dicamba rate increased from 1/512X to 1/8X, predicted No. 1 yield decreased from 127 to 55%, 103 to 69%, 124 to 31%, and 124 to 41% of the non-treated control for applications made 1, 3, 5, and 7 WAP, respectively. Similarly, as dicamba rate increased from 1/512X to 1/8X, predicted marketable yield decreased from 123 to 57%, 107 to 77%, 121 to 44%, and 110 to 53% of the non-treated control for applications made 1, 3, 5, and 7 WAP, respectively. Dicamba residue (5.3 to 14.3 parts per billion) was detected in roots treated with 1/16X or 1/8X dicamba applied 5 or 7 WAP and 1/64X dicamba applied 7 WAP with the highest residue detected in roots harvested from sweetpotato plants treated at 7 WAP. Collectively, care should be taken to avoid sweetpotato exposure to dicamba especially at 1/8X and 1/16X rates during the growing season.

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The Impact of Seasonal Environments in a Tropical Savanna Climate on Forking, Leaf Area Index, and Biomass of Cassava Genotypes

Agronomy ◽

10.3390/agronomy9010019 ◽

2019 ◽

Vol 9 (1) ◽

pp. 19 ◽

Cited By ~ 3

Author(s):

Phanupong Phoncharoen ◽

Poramate Banterng ◽

Nimitr Vorasoot ◽

Sanun Jogloy ◽

Piyada Theerakulpisut ◽

...

Keyword(s):

Leaf Area Index ◽

Leaf Area ◽

Dry Weight ◽

Weather Data ◽

Storage Root ◽

Storage Roots ◽

Area Index ◽

Growing Seasons ◽

The Impact ◽

And Storage

Information on the forking, leaf area index, and biomass of cassava for different growing seasons could help design appropriate management to improve yield. The objective was to evaluate the forking date, leaf growth, and storage root yield of different cassava genotypes grown at different planting dates. Four cassava genotypes (Kasetsart 50, Rayong 9, Rayong 11, and CMR38–125–77) were evaluated using a randomized complete block design with four replications. The cassava genotypes were planted on 20 April, 25 May, 30 June, 5 October, 10 November, and 15 December 2015, and 19 May and 3 November 2016. The soil properties prior to the planting, forking date, leaf area index (LAI), dry weights, harvest index (HI), starch content, and weather data were recorded. The forking date patterns for all of the growing seasons varied depending on the cassava genotypes. The weather caused occurring in the first forking for the Rayong 11 and CMR38–125–77 and the second forking for Rayong 11, but not for Kasetsart 50. The forking CMR38–125–77 had a higher LAI, leaf dry weight, biomass, and storage root dry weight than the non-forking Rayong 9. The higher storage root yields in Rayong 9 compared with Rayong 11 were due to an increased partitioning of the storage roots.

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